How to Get a Sales Tax ID Number for Your UK Business in the US (2026)

So, you’re expanding your UK business into the US market. It’s an exciting move, but it brings a critical piece of admin you absolutely can't sidestep: getting a US sales tax ID. This isn't just a suggestion; for most businesses selling stateside, it's a legal must-do.

This guide will cut through the noise and confusing jargon, giving you a clear, actionable path to get it done right.

Your Playbook for US Sales Tax as a UK Founder

Think of this as your strategic guide to building a compliant US presence from day one. So many founders jump in without a solid plan, only to get hit with application rejections, frustrating delays, and even penalties down the road. We're going to get past the generic advice and show you exactly what to do.

It all starts with one simple, but fundamental, question: do you actually need a sales tax ID? The answer hinges on a concept called 'nexus', which we’ll break down in a bit. But before we even get there, you need to lay the proper groundwork.

Building Your Compliance Foundation

You can't just apply for a sales tax ID (often called a seller's permit or resale certificate) using your UK company details. US state tax agencies have specific hoops for foreign-owned businesses to jump through. Honestly, getting your documents in order before you start is the single best thing you can do to make this process painless.

Here’s what you absolutely must have ready to go:

• A US-based Business Entity: First, you’ll need to formally set up a company in the US. This is usually an LLC or a C Corporation, creating the legal entity that will be on the hook for sales tax.

• An Employer Identification Number (EIN): This is your federal tax ID number from the IRS. It's completely non-negotiable and functions as your business's social security number. You literally cannot apply for a state sales tax ID without one.

• A US Registered Agent and Address: Every official US business entity needs a registered agent with a physical street address in its state of formation. This isn't just a nice-to-have; it's a legal requirement.

A huge point of confusion for founders is thinking an EIN and a sales tax ID are the same thing. They're not. An EIN is a federal number for income tax. A sales tax ID is a state-specific number for collecting and paying sales tax. You'll have one EIN, but you might end up needing several sales tax IDs.

A Roadmap to Getting It Done

Once you have these foundational pieces in place, you can tackle the state registration process with confidence. This guide is designed to give you the full picture, from figuring out if you even need an ID to handling your reporting duties after you get it.

We'll walk through the practical steps of navigating clunky state websites, give you a realistic idea of timelines, and help you think through a multi-state strategy if you're selling all over the country. By the time you're done, you'll have a firm handle on securing your sales tax IDs and setting up your US venture for success.

Do You Actually Need a US Sales Tax ID? Let's Figure It Out

Before you dive into any paperwork, the very first question to ask is: "Am I legally required to get a US sales tax ID?" This isn't a simple yes or no. The answer hinges entirely on a core US tax concept known as nexus.

Think of nexus as having a significant business connection to a specific state. If you have it, you have to play by their sales tax rules. Getting this right is the absolute key to staying compliant. You don't want to waste time and money registering where you don't need to, or worse, miss a legal obligation and face penalties down the road.

For a founder in the UK, this connection usually gets established in one of two ways.

This flowchart breaks down the basic thought process: you enter the US market, figure out if you have nexus, and then move on to getting your sales tax ID.

As you can see, establishing nexus is the critical checkpoint before you start any registration forms.

The Old-School Way: Physical Presence Nexus

Traditionally, nexus was all about having a physical footprint in a state. It’s pretty straightforward, but there are some important nuances for international ecommerce brands.

You likely have physical nexus if you have:

• People on the Ground: Having anyone working for you in a state, even a single remote employee or a regular contractor, is usually enough to create nexus.

• Inventory Storage: This is the big one for UK sellers. Using a third-party logistics (3PL) service or storing products in a warehouse (like those used for Amazon FBA) is a classic trigger. If your stock is sitting in a Texas warehouse, you have nexus in Texas. Simple as that.

• A Physical Location: Any brick-and-mortar presence you own or lease—from a small back office to a temporary pop-up shop—creates an undeniable physical connection.

The Modern Rule: Economic Nexus

The game completely changed a few years back thanks to a landmark Supreme Court case, South Dakota v. Wayfair. Now, you can have nexus without ever setting foot in a state. This is called economic nexus, and it’s triggered purely by your sales volume.

Most states have set specific thresholds, which are typically $100,000 in annual sales or 200 separate transactions into that state. Cross either of those lines, and you're required to register.

Let's say your UK-based SaaS company sells subscriptions to customers in California, and over 12 months, those sales total £80,000. At today's exchange rates, that's well over the $100,000 threshold. Boom—you now have economic nexus and need to get a California sales tax ID, even though your entire team is in London.

To give you a clearer picture, here's a quick look at the thresholds in some of the most common states for international businesses.

Quick Guide: Economic Nexus Thresholds in Key States (2026)

This table summarizes the economic nexus sales thresholds in popular U.S. states for UK businesses. Keep in mind that these are based on sales made in the previous or current calendar year.

State	Annual Sales Threshold	Transaction Threshold
California	$500,000	N/A
New York	$500,000	100 transactions
Texas	$500,000	N/A
Florida	$100,000	N/A
Illinois	$100,000	200 transactions

Remember, this is just a snapshot. You'll need to check the specific rules for any state where you're making significant sales, as the details can vary.

The crucial takeaway is this: you must monitor your sales into every single state separately. Hitting the threshold in one state has no impact on the others, but as your US customer base grows, you could quickly find yourself needing to register in multiple locations. For a deeper analysis, check out our complete guide to sales tax nexus for UK founders.

What About Selling on Amazon or Etsy?

Here's a bit of good news. If you sell through a major online marketplace like Amazon, Etsy, or eBay, marketplace facilitator laws often come into play. In nearly every state with a sales tax, these giant platforms are now legally responsible for collecting and sending in the sales tax on your behalf.

While that's a huge relief, it doesn't mean you can ignore it completely. Some states still require you to register for a sales tax ID even if the marketplace is handling all the tax. Why? So you can properly report your total sales, even if the tax amount you personally owe is zero.

The complexity doesn't stop there. The United States has one of the most intricate sales tax systems globally, with over 11,000 different taxing jurisdictions spread across states, counties, and even cities. It's a lot to navigate, but understanding your nexus obligations is the essential first step.

Your Pre-Application Document Checklist

Before you even think about logging into a state’s tax portal, you’ve got to get your paperwork in order. I've seen countless founders try to apply with just their UK company details, and it's a surefire way to get rejected. US state agencies have a very specific checklist for foreign-owned businesses, and getting this foundation right is absolutely non-negotiable.

Think of this as your prep work. Taking the time to gather these documents first is the single best thing you can do to speed up the whole process. It turns a potential month-long headache of back-and-forth emails with a state official into a smooth, one-shot submission.

The Absolute Must-Have: Your EIN

First up, and most importantly, is your Employer Identification Number (EIN). This is a federal tax ID issued by the IRS. For state tax agencies, it's the main identifier for your US business. You simply cannot get a state-level sales tax ID without having this federal ID first.

Every state application will have a mandatory field for your EIN. If you leave it blank or try to enter your UK company number, the system will kick it back immediately. For founders outside the US, getting an EIN involves a specific process with the IRS that can take a few weeks. If you haven't done this yet, stop everything and make it your top priority.

Our detailed walkthrough on how to get an EIN number for UK founders will guide you through it.

Proving Your Business Is Real: Formation Documents

Next, you need the official formation documents for your US entity. State agencies need hard proof that your company legally exists in the United States before they'll give you a permit to collect their tax.

The exact document depends on your company structure:

• For an LLC: This is your Articles of Organization. It's the core document filed with the state that officially created your LLC.

• For a C Corporation: You’ll need your Articles of Incorporation, which serves the same purpose but for a corporate structure.

Make sure you have a clean digital copy (a PDF is perfect) of this document saved and ready to go. You’ll almost always have to upload it directly into the state’s online portal.

Pro Tip: Double-check that the business name and EIN on your application exactly match what's on your formation documents and your official EIN confirmation letter from the IRS. Even a tiny mistake, like using "Ltd" when it should be "LLC," can cause frustrating delays.

Your Official US Footprint: Registered Agent and Address

Every formal business entity in the US is legally required to have a registered agent. This is a person or service designated to receive official legal mail and state correspondence on your company's behalf. And here's the key part: your registered agent must have a physical street address in the state where your company was formed.

This can't be a P.O. Box. State agencies use this address to verify your company has an official presence. When you fill out your sales tax application, you'll need to provide:

• The full name of your registered agent service.

• The complete physical street address they gave you.

This information confirms to the state that you have a legitimate, state-sanctioned point of contact in their jurisdiction. It's another crucial checkbox that proves your business is set up correctly under US law.

Nailing these three things—your EIN, formation documents, and registered agent details—will put you in the best possible position to get your sales tax ID number quickly and without any trouble.

Alright, you’ve gathered your documents—the EIN, formation papers, and registered agent info are all lined up. Now comes the main event: actually diving into a state’s online portal to register.

This is where the rubber meets the road. For many founders outside the U.S., the thought of tackling official state government forms can be a bit intimidating. But it’s much more straightforward once you know what to look for.

Instead of just saying "fill out the form," I'm going to walk you through the specific fields that tend to cause confusion. We'll use Florida as our guinea pig, since it's a major e-commerce hub and its online system is pretty standard.

What you’re seeing is the Florida Department of Revenue's e-services portal. This is your central hub for everything: applying for your permit (they call it a "Certificate of Registration"), filing your returns down the line, and paying what you owe.

Getting the Key Application Fields Right

As you click through the application, you'll hit a few questions where your answers really matter. They don't just determine whether you get approved; they set the stage for your ongoing compliance workload.

Here are the big ones you'll run into:

• Business & Owner Information: This sounds simple, but precision is everything. You'll need to enter your U.S. company’s legal name, EIN, and physical address. For the address, use your registered agent's details. It is absolutely critical that this information is a carbon copy of what’s on your IRS and state formation documents. Even a small typo can cause delays.

• Business Start Date in the State: This isn't the date you formed your company. It's the date you officially established nexus in that state. For most e-commerce sellers, this is either the date of your first sale to a customer there or the day your inventory first hit a local warehouse (like an FBA center).

• NAICS Code: The North American Industry Classification System (NAICS) is just a fancy government way of categorizing businesses. You’ll need to pick the code that fits you best. For most online stores, 454110 (Electronic Shopping and Mail-Order Houses) is the one you want.

One of the most important parts of the application is estimating your future sales. Don't just pull a number out of thin air. Your projection of taxable sales in the state will directly influence how often you'll be required to file a sales tax return.

Why Your Filing Frequency Matters

Based on that sales estimate, the state will slot you into a filing frequency. This is their schedule for when you need to submit a sales tax return and hand over the tax you've collected.

The usual schedules are:

1. Monthly: For businesses with a high volume of sales.

2. Quarterly: A common middle ground for many small and medium-sized businesses.

3. Annually: Typically reserved for businesses with very low sales in that particular state.

Getting placed on a monthly schedule means 12 filings a year instead of just four, which is a lot more administrative hassle. This is why a realistic, even conservative, sales estimate is so important when you're starting out. If you blow up, you can always ask the state to adjust your frequency later. For a deep dive into this for a specific state, our expert guide to getting a Florida reseller's permit breaks it down further.

What to Expect for Timelines and Fees

So, how long does this all take? It really depends on the state. The good news is that most states have moved online, which has massively sped things up.

• Instant or Near-Instant: Some states are incredibly efficient. Florida, for example, has a slick automated system that can issue your sales tax ID in a few business days, sometimes even faster.

• Weeks of Manual Review: Then there are states like California, which tend to have a more hands-on review process. For a foreign-owned entity, it's not unusual for these applications to take 2-4 weeks, sometimes longer.

And what about the cost? You'll be happy to hear that many states—like Texas and Florida—don't charge a fee to register for a sales tax ID. Others do, though the costs are usually minimal. Pennsylvania, for instance, is free to register but requires a renewal every five years. Wisconsin, on the other hand, charges a $20 Business Tax Registration fee for a permit that's good for two years.

The key is to check the state's Department of Revenue website for the latest fee schedule before you start. Having all your documents ready and filling out the application with care is your best defense against errors that can turn a simple registration into weeks of frustrating delays.

What to Do After You Get Your Sales Tax ID

https://www.youtube.com/watch?v=95lB2K21Fec

Receiving that email with your official sales tax ID number feels like a huge win. It’s the green light you’ve been waiting for to start selling legally in a new state. But this is where the real work of staying compliant kicks in. Getting the ID is just the starting line; now, you have ongoing responsibilities to stay in the state’s good graces.

Your new sales tax ID number, often called a seller's permit, is what authorizes you to legally collect and hand over taxes on behalf of a state government. Across the U.S., any business selling taxable products or services needs this unique identifier from the state's tax agency before making their first sale. You can learn more about how this ID is crucial for your business operations on savantlabs.io.

Start Tracking and Collecting Sales Tax

Your most immediate and critical job is to start collecting the correct sales tax on every taxable sale to customers in that state. This means jumping into your e-commerce platform—whether that’s Shopify, WooCommerce, or something else—and configuring it to apply the right tax rate at checkout.

This isn't always straightforward. Rates can change from one city or county to the next, and special taxing districts add another layer of complexity. For this reason, most businesses find that an automated tax calculation tool is a lifesaver. You need to track not just your total sales, but the exact amount of tax you’ve collected for that specific state.

Key Takeaway: The moment your sales tax ID is active, your responsibility to collect begins. Don't make the mistake of waiting until your first filing deadline to figure out your collection process. Get it set up immediately to avoid a major headache later on.

Understand Your Filing Schedule

When the state approved your application, they didn't just give you a number; they also assigned you a filing frequency. This is the schedule that tells you how often you must file a sales tax return and remit the taxes you've collected.

Your assigned frequency is almost always based on your estimated or actual sales volume:

• Monthly: This is typically for businesses with higher sales volumes.

• Quarterly: A very common schedule for many small to mid-sized businesses.

• Annually: Usually reserved for businesses with very low sales in that state.

It's absolutely vital to know your schedule and get those deadlines in your calendar. Missing a deadline can trigger automatic penalties and interest charges, even if you owe nothing for that period.

The Art of Filing a Return

Filing a sales tax return means reporting your total gross sales, your taxable sales, and the total sales tax you collected during the filing period. Every state has its own specific form—if you’re registered in Florida, for instance, you’ll get very familiar with their Form DR-15.

You'll file this return through the same state online portal you used to register. After you submit the report, you’ll need to make the payment, which is usually done via an electronic bank transfer (ACH) from a U.S. bank account.

Here’s a crucial tip for new filers: you must file a return even if you had zero sales for the period. This is called a "zero return," and it's how you tell the state you're still in business but just had no taxable activity. Failing to file a zero return is treated just like failing to file a regular one and will rack up penalties.

Manage Exemptions and Renewals

Beyond filing, a few other duties are on your plate. If you sell to other businesses that plan to resell your products (wholesale), you'll need to get a valid resale certificate from them. This document is your proof for why you didn't charge them sales tax and is your key defense in an audit.

Finally, keep in mind that some sales tax permits don’t last forever. While many states, like Texas, issue permits that are good for as long as you’re in business, others require you to renew them. Pennsylvania, for example, requires renewal every five years, while Wisconsin requires it every two. Make a note of these dates to ensure your permit stays active and your U.S. operations continue without a hitch.

Common Questions from UK Founders

Over the years, we've helped hundreds of UK entrepreneurs get set up in the States. After a while, you start to see the same questions come up time and time again. Navigating U.S. sales tax from across the pond can feel a bit abstract, so let's tackle the most common sticking points head-on.

What's the Difference Between an EIN and a Sales Tax ID?

This is, without a doubt, the question we get asked most. Getting this right is the foundation of your entire U.S. compliance journey.

Here’s the simplest way to think about it:

An Employer Identification Number (EIN) is your federal ID card, issued by the IRS. It’s the one-and-only national identity number for your entire U.S. business, used for things like federal income tax and hiring. You will only ever have one EIN for your U.S. company.

A Sales Tax ID Number, on the other hand, is a state-level permit. Its only job is to manage sales tax in one specific state. Because sales tax is handled state by state, you’ll need a completely separate and unique sales tax ID for every single state where you have nexus.

You absolutely must get your federal EIN first. It's a non-negotiable prerequisite for nearly every state sales tax application. Trying to apply for a state permit without one is like trying to get a UK driving licence with no proof of who you are—it’s just not going to happen.

Do I Really Need a US Bank Account to Get a Sales Tax ID?

Technically, no. You can usually get through the registration process without having a U.S. bank account set up. The application is more concerned with your business details, your EIN, and why you have nexus.

But practically speaking? It's essential. The real problem comes later, when it's time to actually pay the sales tax you’ve collected. States want their money via methods like an ACH transfer from a U.S. bank. Trying to make these payments from a UK account is often impossible or, if you find a way, it's incredibly expensive and full of potential delays.

Our advice is simple: the minute your EIN is confirmed, make opening a U.S. business bank account your very next call. It makes paying your taxes simple, on time, and far cheaper in the long run.

How Long Does This Actually Take?

The timeline for getting your sales tax ID can vary wildly depending on the state. It really comes down to how modern their online system is and how much manual review is involved.

• The Fast Lane (A Few Business Days): States with slick, automated portals, like Florida, can be remarkably quick. If your application is perfect and all your documents are ready, you could have your permit in 3-5 business days.

• The Scenic Route (Several Weeks): Other states, like California, have a much more hands-on review process, especially for businesses with foreign owners. It’s not unusual for these to take 2-4 weeks, and sometimes even longer if they have follow-up questions.

Any mistake on your application—a mismatched name, a typo in your EIN, a missing document—will throw you to the back of the line and cause serious delays. The best way to speed things up is to have your EIN, formation documents, and registered agent details completely sorted before you even start the application.

Do I Have to Register in All 50 States?

Absolutely not. This is a common fear, but thankfully it’s unfounded. You only need a sales tax ID in the specific states where you have nexus.

As we've covered, this "nexus" connection can be triggered by a physical presence (like inventory sitting in a warehouse) or by crossing an economic threshold (like hitting $100,000 in sales to that state).

The key is to keep an eye on your sales activity in every state. As your business grows, you might trip the economic nexus wire in a new state, and that’s your cue to register there. Think of it as an ongoing task, not a one-and-done setup.

---

Navigating U.S. tax compliance can be a major headache, but it doesn't have to put the brakes on your growth. Set Up Stateside offers end-to-end accounting and tax services built specifically for UK founders. We handle everything from sales tax registration to annual filings so you can focus on what you do best. Learn more about how we can support your U.S. expansion.