The Complete Sales Tax Compliance Services Guide for Business Owners

Running a business is hard enough without worrying about sales tax in 45 different states. But if you’re selling across state lines, sales tax compliance isn’t optional. It’s the law.

The good news? You don’t have to figure it all out alone. This guide will walk you through everything you need to know about sales tax compliance services and how to get your business on the right track.

What Are Sales Tax Compliance Services?

Sales tax compliance services help businesses manage their sales tax obligations across multiple states. These services handle everything from determining where you have nexus to filing returns and managing audits.

Sales tax compliance means following all the rules for collecting, reporting, and paying sales tax in every state where you do business. This includes:

• Knowing where you have nexus (a tax obligation)
• Registering with state tax authorities
• Collecting the right amount of tax from customers
• Filing returns on time
• Paying what you owe when it’s due
• Keeping accurate records

Sounds simple, right? It’s not. Each state has its own rules, rates, filing schedules, and penalties. And those rules change constantly.

Do You Need Sales Tax Compliance Services?

Not every business needs professional help with sales tax. But most do.

Signs You Need Professional Sales Tax Compliance Services

You probably need sales tax compliance services if:

• You sell in more than 3 states
• You’re not sure where you have nexus
• You’ve fallen behind on filing returns
• You’ve received a notice from a state tax department
• You’re spending more than 5 hours a month on sales tax
• You’ve made mistakes on past returns
• You’re using Amazon FBA or other third-party fulfillment
• You sell digital products or services
• Your business is growing quickly

Types of Sales Tax Compliance Services

Different businesses need different levels of help. Here are the main types of sales tax compliance services available.

Sales Tax Compliance Services Comparison Table

Step-by-Step: How Our Sales Tax Compliance Services Work

Step 1: Assess Your Current Situation

Before you can fix your sales tax issues, you need to understand what you’re dealing with. Our sales tax compliance services start with a thorough assessment of your current situation.

What to do:

• Pull sales reports for all states for the past 3 years
• List any physical presence you have (offices, warehouses, employees)
• Note any third-party fulfillment arrangements
• Check if you’ve received any notices from states
• Review what you’re currently doing for sales tax

How long it takes: 1-3 days

Step 2: Determine Where You Have Nexus

Nexus is the connection that creates a tax obligation. We’ll help you identify exactly where you have nexus obligations.

Common nexus triggers:

• Physical presence (office, warehouse, employees)
• Economic nexus ($100,000+ in sales or 200+ transactions in most states)
• Affiliate nexus (relationships with in-state businesses)
• Click-through nexus (paying for in-state advertising)
• Marketplace nexus (using platforms like Amazon FBA)

What to do:

• Compare your sales to each state’s thresholds
• Identify when you first crossed each threshold
• Document your nexus analysis

How long it takes: 3-7 days (depending on complexity)

Step 3: Calculate Your Exposure

If you haven’t been collecting sales tax where you should have been, you need to know what you might owe. We can accurately calculate your exposure.

What to calculate:

• Uncollected sales tax by state
• Potential penalties (varies by state)
• Interest charges
• How many years back you might owe

What to do:

• Multiply sales by each state’s average tax rate
• Add estimated penalties (often 10-25% per year)
• Add interest (varies by state, usually 3-12% per year)

How long it takes: 2-5 days

Step 4: Choose Your Compliance Strategy

Based on your exposure, you have several options. We can help you choose the best strategy for your situation.

Strategy comparison:

What to do:

• Review your options with us
• Weigh the costs and risks of each approach
• Make a decision and commit to it

How long it takes: 1-2 weeks (including consultation)

Step 5: Register in Required States

Once you know where you have nexus, you need to register. Sales tax compliance services handle all the registration paperwork for you.

What you’ll need:

• Federal EIN
• Business formation documents
• NAICS code
• Estimated sales by state
• Bank account information (for some states)

What to do:

• Complete registration applications for each state
• Pay any required fees
• Wait for sales tax permits (can take 2-8 weeks)
• Set up accounts in state systems

How long it takes: 4-12 weeks for all states

Step 6: Set Up Collection Systems

You need to collect the right amount of tax from your customers. Sales tax compliance services often include help setting up your collection systems.

What to set up:

• Configure your shopping cart or POS system
• Install sales tax automation software (recommended)
• Create exemption certificate procedures
• Train your team

Popular tax automation tools we partner with:

• Avalara
• Vertex

What to do:

• Choose a tax calculation method (manual or automated)
• Set up tax rates in your system
• Test thoroughly before going live
• Document your procedures

How long it takes: 1-4 weeks

Step 7: File Returns on Schedule

Each state has different filing frequencies (monthly, quarterly, or annual). This is where our ongoing sales tax compliance services really pay off.

Filing calendar basics:

• High-volume states: Usually monthly
• Medium-volume states: Usually quarterly
• Low-volume states: Usually annual
• Due dates: Typically 20th-30th of the month after the period ends

What to do:

• Create a filing calendar
• Set up reminders
• Gather sales data before each deadline
• File even if you owe nothing (in most states)

How long it takes: 2-10 hours per month (depending on number of states)

Step 8: Remit Payments

Filing the return isn’t enough. You also have to pay what you owe. We can track and manage these payments for you.

What to do:

• Set aside sales tax collections in a separate account
• Never use sales tax money for business expenses
• Pay electronically (most states require this)
• Keep confirmation receipts

How long it takes: 30 minutes to 2 hours per filing period

Step 9: Maintain Records

You need to keep detailed records in case of an audit. We can maintain organized records on your behalf.

What to keep:

• Sales records by state
• Exemption certificates
• Filed returns and confirmations
• Payment receipts
• Correspondence with states
• Nexus documentation

How long to keep it: Most states require 3-4 years, but keep it for 7 years to be safe

What to do:

• Set up a filing system (digital is best)
• Back up everything
• Review quarterly to ensure you’re not missing anything

How long it takes: Ongoing – build it into your routine

Step 10: Monitor and Adjust

Sales tax compliance isn’t set-it-and-forget-it. Quality sales tax compliance services include ongoing monitoring and adjustments.

What to monitor:

• Sales in states where you’re close to nexus thresholds
• Changes in state laws
• New locations or employees
• New product types
• Changes in your business model

What to do:

• Review nexus status quarterly
• Stay informed about law changes
• Register in new states as needed
• Update your systems when rates change

How long it takes: 2-4 hours per quarter

Common Sales Tax Compliance Mistakes

Even with the best intentions, businesses make mistakes. Here are the most common ones that our sales tax compliance services help you avoid.

Mistake 1: Waiting Until You Get Caught

Many businesses ignore nexus until they receive a letter from a state. By then, penalties and interest have piled up.

The fix: Be proactive. Assess your nexus regularly and address issues before states find you. We can monitor your obligations continuously.

Mistake 2: Thinking You’re Too Small to Worry

States are getting better at finding small businesses. And they don’t care about your size when it comes to penalties.

The fix: Take compliance seriously from day one, even if you’re a small business. Our saless tax compliance services are affordable even for smaller companies.

Mistake 3: Using the Wrong Tax Rates

Tax rates can vary by city, county, and even special districts. Using the wrong rate is a common mistake.

The fix: Use tax automation software. It’s worth every penny, and it’s often included with sales tax compliance services.

Mistake 4: Not Collecting Exemption Certificates

If you sell to tax-exempt buyers without proper documentation, you could owe the tax yourself.

The fix: Always get exemption certificates before making tax-free sales. We can manage your exemption certificate process.

Mistake 5: Missing Filing Deadlines

Even if you owe nothing, you often still need to file. Missing deadlines can trigger penalties.

The fix: Set up a calendar with reminders, or the safest way is to outsource let us handle this for you.

Mistake 6: Mixing Sales Tax with Business Money

Using collected sales tax for business expenses is called trust fund diversion. It’s serious.

The fix: Keep sales tax in a separate account and never touch it.

Mistake 7: Ignoring Notices from States

That letter from the state won’t go away if you ignore it. It will only get worse.

The fix: Respond immediately. Call us if you’re not sure what to do – 720.878.2280.

Cost of Not Using Sales Tax Compliance Services

If you don’t comply and get caught:

• Back taxes: 100% of what you should have collected
• Penalties: 10-25% per year (varies by state)
• Interest: 3-12% per year (varies by state)
• Audit costs: $5,000-$50,000+
• Legal fees: $10,000-$100,000+ if it goes to court
• Criminal penalties: Possible in extreme cases

One year of non-compliance can easily cost you more than a decade of professional sales tax compliance services.

How Nexus Accountant’s Sales Tax Compliance Services Can Help

At Nexus Accountant, we specialize in comprehensive sales tax compliance services for businesses selling across multiple states.

Our Sales Tax Compliance Services Include

Nexus Studies We analyze your business to determine exactly where you have tax obligations and what your exposure might be.

Voluntary Disclosure Agreements We negotiate with states on your behalf to reduce penalties and limit how far back you have to pay.

Registration Services We handle all the paperwork to get you registered in the states where you need to be.

Ongoing Compliance We manage your filing, remittance, and monitoring so you can focus on running your business.

Audit Defense If you face a sales tax audit, we represent you and fight for the best possible outcome.

Consulting and Strategy We help you structure your business to minimize sales tax obligations legally.

Why Choose Nexus Accountant’s Sales Tax Compliance Services

We’re nexus specialists This is all we do. We’re not generalists trying to be experts in everything.

We know the states We’ve worked with every state. We know which ones are aggressive and which ones are reasonable.

We save you money Our clients typically save more in penalties and time than they pay us for our sales tax compliance services.

We reduce your stress Sales tax compliance is complicated. We make it simple.

We’re responsive When you call or email, you get a real person who knows your account.

Getting Started with Our Sales Tax Compliance Services

Ready to get your sales tax compliance under control? Here’s how to start:

1. Call us at 720.878.2280 or visit nexusaccountant.com
2. Schedule a free consultation – we’ll review your situation
3. Get a clear plan – we’ll tell you exactly what needs to happen
4. Let us handle it – we’ll take it from there

Don’t wait until you get a letter from a state. The longer you put it off, the more it will cost.

Frequently Asked Questions About Our Sales Tax Compliance Services

How much do sales tax compliance services cost?

The cost depends on how many states you operate in and what services you need. Here’s a general breakdown:

• DIY with software: $50-$300 per month plus your time
• Professional filing services: $200-$500 per month for most small to mid-size businesses
• Full-service compliance: $400-$1,000+ per month depending on complexity
• One-time services: Nexus studies ($1,500-$5,000), VDAs ($2,500-$10,000 per state), registrations ($150-$300 per state)

Our professional sales tax compliance services are much cheaper than the penalties and interest you’ll face if you don’t comply. Most businesses find that our help actually saves them money.

Do I really need to collect sales tax in states where I don’t have a physical presence?

Yes. Since the 2018 Supreme Court decision in South Dakota v. Wayfair, states can require you to collect sales tax based on your economic activity in the state, even if you have no physical presence there.

Most states now have economic nexus thresholds. If you exceed $100,000 in sales or 200 transactions in a state, you typically need to collect tax there. Some states have different thresholds, and a few don’t have transaction count requirements.

If you sell online to multiple states, you almost certainly have economic nexus somewhere. Our sales tax compliance services can help you identify exactly where.

What happens if I’ve been selling without collecting sales tax?

If you haven’t been collecting sales tax where you should have been, you have several options:

Best option: File a Voluntary Disclosure Agreement (VDA). This allows you to come forward before the state finds you. In exchange, states typically reduce or eliminate penalties, limit how far back you have to pay, and give you immunity from criminal prosecution. Sales tax compliance services handle VDA negotiations.

Second option: Register and start collecting going forward. This is simpler but doesn’t protect you from audits for past periods.

Worst option: Do nothing and hope you don’t get caught. This is risky. States are getting better at finding non-compliant businesses, and the penalties keep growing.

The key is to act quickly. The longer you wait, the more you’ll owe and the fewer options you’ll have.

How do I know which states I have nexus in?

You have nexus in a state if you meet any of these conditions:

• Physical presence: You have an office, warehouse, employee, or inventory in the state
• Economic nexus: Your sales exceed the state’s threshold (usually $100,000 in sales or 200 transactions)
• Affiliate nexus: You have business relationships with companies in the state
• Click-through nexus: You pay for advertising from in-state affiliates
• Marketplace nexus: You use third-party fulfillment (like Amazon FBA) that stores your inventory in the state

The rules vary by state and change frequently. Our services include a nexus study that gives you a clear answer about where you have obligations.

Can I just let my shopping cart software handle sales tax?

Shopping cart software can help with tax calculation, but it can’t handle everything. Here’s what it does and doesn’t do:

What it does:

• Calculate the correct tax rate for each sale
• Collect tax from customers
• Track your sales by state

What it doesn’t do:

• Determine where you have nexus
• Register you with states
• File your sales tax returns
• Remit payments to states
• Handle exemption certificates
• Represent you in an audit

Software is a great tool, but it’s just one piece of the puzzle. You still need to handle registration, filing, payment, and record-keeping. That’s where our sales tax compliance services come in.

How often do I have to file sales tax returns?

It depends on how much tax you collect in each state. States assign filing frequencies based on your volume:

• Monthly: High-volume sellers (varies by state, often $500+ per month in tax)
• Quarterly: Medium-volume sellers (the most common frequency)
• Annual: Low-volume sellers

When you first register, most states start you on monthly or quarterly filing. After a year or two, they may change your frequency based on your actual collections.

You typically have to file even if you owe nothing for that period. Missing a filing can trigger penalties, even if no tax was due. We can track all your filing deadlines and handle the returns for you.

What’s a Voluntary Disclosure Agreement (VDA)?

A Voluntary Disclosure Agreement (VDA) is a deal you make with a state when you haven’t been collecting sales tax but should have been. We specialize in negotiating VDAs.

Here’s how it works:

• We contact the state for you and admit you should have been collecting tax
• We provide information about your sales and calculate what you owe
• The state agrees to reduced penalties (often waived completely)
• The state limits the lookback period (often to 3-4 years instead of the full statute of limitations)
• You agree to register and collect tax going forward
• You get immunity from criminal prosecution

VDAs can reduce your total tax bill by 50% or more compared to what you’d owe if the state came after you first. But you have to apply before the state contacts you. Once they reach out, it’s too late for a VDA.

What happens during a sales tax audit?

A sales tax audit is when a state reviews your records to make sure you’ve been collecting and remitting the correct amount of tax. Here’s what typically happens:

Notice: You receive a letter saying you’ve been selected for audit.

Information request: The state asks for records (sales reports, exemption certificates, filed returns, etc.).
Review: An auditor examines your records, usually looking back 3-4 years.
Findings: The auditor calculates any underpayment of tax.
Assessment: You receive a bill for any tax owed, plus penalties and interest.
Appeal: You can dispute the findings if you disagree.

Audits can take 3-12 months and cost thousands in professional fees, even if you don’t owe anything. The best defense is good record-keeping and accurate filing from the start.We include audit defense if you need it.

If you receive an audit notice, contact a us immediately at 720.878.2280. Don’t try to handle it yourself.

Do I need to collect sales tax on shipping charges?

It depends on the state. There’s no federal rule, and states handle this differently:

• Always taxable: Some states always tax shipping (like Texas)
• Never taxable: Some states never tax shipping (like California, if separately stated)
• Conditional: Some states tax shipping only if it’s included in the product price or if the product itself is taxable

The rules can also depend on whether shipping is mandatory or optional, separately stated or included in the price, and whether you’re shipping taxable or exempt items.

This is one of many reasons why our sales tax compliance services are worth the investment. We use automation software that knows these rules for every state and applies them correctly.

Take the Next Step

Sales tax compliance doesn’t have to be overwhelming. With our services and the right systems, you can get compliant and stay compliant without it taking over your life.

At Nexus Accountant, we’ve helped many businesses just like yours navigate the complex world of multi-state sales tax. We know what works, what doesn’t, and how to get you where you need to be as quickly and painlessly as possible.

Ready to get started with our sales tax compliance services?

Call us at 720.878.2280 or visit nexusaccountant.com to schedule your free consultation. We’ll review your situation, answer your questions, and give you a clear plan of action.

Don’t wait until you get a notice from a state. The time to act is now.

This guide is for informational purposes only and does not constitute legal or tax advice. Sales tax rules vary by state and change frequently. Consult with a qualified tax professional about your specific situation.