You’re running a business in Martin County, and you know you owe sales tax—but you’re not entirely sure how much, what triggers it, or whether you’re filing it right. Sales tax rules look simple on the surface. Then you sell a service to one client, a product to another, and suddenly you’re wondering if they’re taxed the same way. Florida’s system adds a county surtax on top of the state rate, which means your Martin County rate is different from what a business just across the county line pays. The confusion costs time, and the mistakes cost money. This guide walks you through what you owe, how to calculate it, and how to file it correctly on the Florida Department of Revenue system—so you can file with confidence and keep more of what you earn.
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Does this apply to your business in Florida?
If you make sales in Martin County, Florida, you must collect and remit sales tax unless your product or service is specifically exempt. Florida’s rule is straightforward: tangible personal property is taxable unless the law says otherwise; services are not taxable unless they’re explicitly listed in Florida Statute 212. The Florida Department of Revenue publishes the complete list of taxable services, and if your business isn’t on it, your service sales are likely not subject to sales tax—but tangible goods you sell are.
How the rate works
Florida’s sales tax is built in two parts: a 6% state rate and a county surtax that varies by county. Martin County has its own surtax rate that adds to the state 6%. The combined rate you use depends on where the customer is located when the sale happens. To find the exact current combined rate for Martin County, check the Florida Department of Revenue website or use their sales tax calculator—rates can change, and you want the figure that’s in effect when you file.
The surtax system means that even though you’re in one county, your rate might differ if you make sales to customers in other Florida counties. Each sale is taxed at the rate of the county where the customer receives the product or service. That’s why knowing your customer’s location matters, especially if you’re selling across county lines or taking orders online.
How to file step by step
Filing sales tax in Florida happens through the DR-15 form on the Florida Department of Revenue website. The process is monthly (unless you’re a very small seller and qualify for a different schedule). You report your taxable sales for the month, multiply by the combined rate (6% state + Martin County surtax), and remit the tax by the 20th of the following month.
Here’s the filing process in order. First, log into your Florida Department of Revenue account or create one if you haven’t already. Navigate to the DR-15 form section for sales tax. Enter your sales figures for each taxability category—taxable sales and non-taxable (exempt) sales. The system will calculate the tax owed based on the rate for your filing location. Review the calculation carefully: multiply your taxable sales by your combined rate to verify the total matches.
Next, enter any tax credits or adjustments that apply to your business (for example, bad debt you’ve written off, or a previous month’s overpayment). The net amount is what you owe. Submit the form and arrange payment by the 20th deadline. You can pay online through the same system, by check, or by other methods the Department of Revenue accepts. Keep records of your sales and tax payments for at least five years—the Department of Revenue may ask for them if your return is selected for review.
The step-by-step process is walked through in detail here, including how to categorize your sales and how to handle county rate changes. If you’re unsure whether a specific sale is taxable, you can also request a private letter ruling from the Florida Department of Revenue—it takes longer but gives you written confirmation.
Common mistakes
One frequent mistake is taxing a service that isn’t on the Florida Department of Revenue’s taxable list. Many service businesses assume all services are taxed. They’re not. Consulting, accounting, legal advice, repair services (in most cases), and labor are generally not taxable—but certain services like telecommunications, hotel/rental accommodations, and pest control are. If you’re unsure, check the taxable services list on the Department of Revenue website before you charge tax. The fix is simple: categorize your sales correctly when you file, and if you’ve taxed customers in error, you can refund that amount and adjust your next return.
A second common error is using an outdated combined rate. County surtax rates can change, and the state rate has been stable, but the combined total varies by location and by time. Filing with last year’s rate or a rate you haven’t verified recently means you’ll under-collect or over-remit. Your defense is to check the current rate on the Department of Revenue calculator before each filing period. Updating this once a month takes five minutes and prevents months of recalculation later.
A third mistake is mixing up where the sale happened. If you’re a contractor or seller who serves multiple counties, you must apply the rate of the county where the customer receives the product or service, not where you’re based. Say you’re in Martin County but install a roof in Broward County—you use Broward’s rate for that sale. Keep records that show the customer’s location so you can prove you taxed correctly if the Department of Revenue reviews your return.
The fourth mistake is failing to file at all or filing late without a reasonable exemption. The deadline is the 20th of the following month. Missing it triggers penalties and interest on the unpaid tax. If you can’t file on time, request an extension in writing before the deadline—you still owe the tax, but a timely extension request may reduce or eliminate penalties. Set a calendar reminder for the 15th of each month so you have five days to gather numbers and file.
Frequently Asked Questions
What if I’m a service-based business in Martin County—do I charge sales tax?
Only if your service is on Florida’s taxable services list. Most services—consulting, labor, repairs, accounting—are not taxable. Check the Florida Department of Revenue taxable services list, or ask your CPA if you’re unsure. If your service isn’t listed, you don’t charge tax.
Do I need a sales tax permit to sell in Martin County?
Yes. If you make taxable sales in Florida, you must register with the Florida Department of Revenue and get a sales tax permit. The process is free and done online on the Department of Revenue website. Once you have a permit, you can begin collecting tax immediately.
When do I file the DR-15 form—monthly or quarterly?
Most small businesses file monthly. Your filing frequency depends on your sales volume and is set by the Florida Department of Revenue when you register. The deadline is the 20th of the following month, regardless of whether you file monthly or on another schedule. Confirm your assigned frequency in your Department of Revenue account.
What happens if I file late or underpay sales tax in Martin County?
Late filing and underpayment can result in penalties and interest calculated on the unpaid amount. The exact penalty depends on how late you are and whether the error was intentional or negligent. If you realize you’ve made a mistake, file an amended return and pay the difference as soon as possible. Contact the Department of Revenue if you believe you have a valid reason for the delay.
Can I deduct sales tax I’ve already paid on business purchases?
No, not directly on your sales tax return. However, sales tax you pay on inventory and supplies that you later resell may be recovered through a resale certificate, which exempts you from paying tax on those goods. Keep resale certificates from your vendors and use them when purchasing inventory. Your CPA may also advise on how business purchases affect your income tax.
This article is for general educational purposes and isn’t a substitute for advice from a licensed CPA or tax attorney. Rules vary by jurisdiction and change over time—always confirm current requirements with the Florida Department of Revenue or your advisor.
Sales tax compliance in Martin County comes down to three habits: know whether you’re taxable, use the current rate, and file on time. Each one is simple to do once, but the compound effect of ignoring even one can create months of back-and-forth corrections. Your goal isn’t to become a tax expert—it’s to set up a repeatable process so you file confidently and don’t have to think about it again. The resources at the Florida Department of Revenue and our Florida sales tax guide cover the specifics for your situation. Once you file two or three times, the pattern becomes automatic.
This article is for general educational purposes and isn’t a substitute for advice from a licensed CPA or tax attorney. Rules vary by jurisdiction and change over time — always confirm current requirements with the Florida Department of Revenue or your advisor.
See how this fits into the bigger picture in our Florida sales tax guide, which covers county rates and filing deadlines in detail.