How to Submit Sales Tax in 2026: A Modern Guide for Growing Businesses

If you're looking to stay sales tax compliant without the headache, this step-by-step guide breaks it all down—from tracking nexus to filing and paying on time. 

Here, you’ll learn:

• How sales tax works

• Where and when to file

• A simple, step-by-step way to submit sales tax

• Common pitfalls to avoid

• How automation can make tax compliance easier

What is sales tax and who needs to pay it?

Sales tax is a consumption tax imposed on the sale of goods and certain services, which the seller collects from the customer and then remits to state or local tax authorities. To owe sales tax collection and filing obligations, a business must have a sales tax nexus in a state, meaning enough connection to trigger that state’s tax rules.

There are two main types of nexus:

• Physical Nexus: When a business has a physical presence in a state such as a store, warehouse, inventory or employees.

• Economic Nexus: When a business meets sales volume or transaction thresholds in a state, even without a physical presence there.

States set their own economic nexus thresholds and these rules vary by jurisdiction.

Taxable vs Non-Taxable Sales

Certain sales that would otherwise be taxable can be claimed as exempt if the buyer provides a valid exemption certificate. It’s important for sellers to collect and retain these certificates in case of audit, because tax authorities may require documentation to support the tax-exempt treatment of the transaction.

When and where you must file

Sales tax filing frequency is assigned by each state and is usually monthly, quarterly or annually, depending on how much sales tax your business collects. Higher-volume sellers typically file more frequently.

In the USA, you're required to file sales tax returns in every state where your business has nexus, whether that nexus is physical or economic.

Even if you didn’t make any taxable sales during a filing period, most states still require you to submit a “zero return”. Skipping these filings can still trigger penalties.

Missing deadlines or filing incorrectly will result in late fees, interest charges and additional penalties, which vary by state but can add up quickly over time.

Managing multiple filing schedules and state requirements manually can become overwhelming fast which is why many businesses turn to automated platforms like Kintsugi to help track nexus, deadlines and filings in one place.

Steps to submit sales tax (traditional manual process)

Detailed below is a basic walkthrough of how to file state sales tax and how to submit sales tax returns manually.

Step 1: Gather Your Sales Data

Before you begin filling out any forms, collect all of your sales information for the filing period:

• Total sales from all channels and states where you have nexus.

• Taxable vs non-taxable revenue, based on what products/services were sold.

• Exemptions and refunds that affect your net taxable amount.

Step 2: Calculate Sales Tax Collected

Once you have your data:

• Apply the correct state and local tax rates to each taxable transaction, this varies by location and product/service.

• Account for product-specific taxability, as some states tax services or digital goods differently.

These calculations determine how much you actually need to remit on your sales tax return.

Step 3: Register With Each State Where You Owe Sales Tax

Before you can submit returns, you must be registered with every state where you have sales tax nexus.
This typically involves:

• Applying for a sales tax permit through each state’s Department of Revenue

• Providing business details such as legal entity name, EIN, business address and start date of taxable activity

• Receiving a sales tax ID or permit number for that jurisdiction
  You can’t legally collect or file sales tax in a state until this registration is complete.

Step 4: Submit Your Sales Tax Return

Once registered and totals are calculated:

• Log into each state’s Department of Revenue portal where you owe tax

• Enter gross sales, taxable sales and tax collected on the official return form for that state

Step 5: Submit the Return

Once the form is complete:

• File electronically (the preferred method for most states) or submit by mail if e-filing isn’t available.

• Save confirmation receipts or acknowledgement numbers. These are your proof of filing.

Step 6: File and Pay Sales Tax

Finally, after submitting the return:

• Remit your payment to the state by ACH, direct debit, credit card or another approved method.

• Match payment to each submitted return to ensure records reconcile and avoid mismatches on audit.

How automation transforms sales tax filing

The problem with manual filing

Managing sales tax manually becomes tedious as businesses scale and sell across multiple states:

• Multiple states = multiple portals: Each state has its own filing system, deadlines and forms requiring logging into separate portals for each jurisdiction. 

• Constant rate changes: Sales tax laws and rates change frequently making it hard to manually keep tables and rules up to date.

• Risk of miscalculations: Manual calculations are prone to human error, especially with thousands of local tax rates and complex tax rules.

• Hours lost every month: Repetitive tasks like updating tables, preparing returns and filing multiple reports take significant time.

• Higher audit exposure: Errors and inconsistencies in manual systems increase the risk of audits and penalties when tax authorities review filings.

Automation: The smarter way

Sales tax automation tools simplify compliance by centralizing and streamlining complex processes:

• Real-time tax calculations: Automated systems apply up-to-date tax rates and rules instantly across all jurisdictions where you do business.

• Automatic nexus tracking: Automation monitors your sales activity and alerts you when you cross a state’s nexus thresholds, reducing compliance risk.

• Centralized dashboards: All sales tax data, deadlines, filings and exemptions can be viewed and managed from one interface across all states.

• Returns prepared and filed from one system: Many automated platforms generate and submit sales tax returns for each jurisdiction on your behalf, reducing manual effort.

Common sales tax filing questions

1. What happens if I file in the wrong state?

If you file in a state where your business doesn’t have nexus, that return can be rejected or trigger compliance reviews. Filing in the wrong jurisdiction can delay payment posting and increase administrative work correcting it later.

2. What if I use the wrong tax rate?

Using incorrect tax rates can lead to under-collecting or over-collecting tax. Under-collecting may result in you owing the difference plus penalty/interest, while over-collecting can upset customers and require refunds.

3. Do I need to file if I’ve had no sales?

Yes, in most states you still need to file a “zero return” when no tax was collected during the reporting period. Failing to file on time can result in penalties even if no tax is owed.

4. What if I miss a deadline?

Missing a filing deadline typically leads to late fees, interest and possible compliance flags. Penalty amounts vary by state, but repeated late filings increase your risk of audits and financial charges.

5. How do I avoid these mistakes?

Maintain good record-keeping, stay updated on nexus and rate changes and consider adopting sales tax automation tools like Kintsugi that automatically calculate taxes, track nexus thresholds, generate returns and remind you of deadlines.

Ready to simplify your sales tax compliance?

Sales tax doesn’t have to be complicated. If you’re tired of juggling multiple tax portals, spreadsheets and constantly changing deadlines, there’s a smarter way.

Platforms like Kintsugi can automate your entire sales tax process from real-time tax calculations and nexus tracking to filing sales tax returns and handling payments, all from a single dashboard.

Explore how automation can remove manual effort, reduce errors and give your team back valuable time.

Book a free demo with a Kintsugi tax expert today and see how automated sales tax filing can transform your business.