Sales Tax Calculator
Calculate multi-rate sales tax for ecommerce transactions including state, county, and city rates.
Results
Visualization
How It Works
Sales tax for ecommerce is collected based on where your customer is located (destination-based sourcing in most states) and whether your business has 'nexus' in that state. Nexus is a legal connection to a state that triggers your obligation to collect and remit tax — it can be established by physical presence, employees, or exceeding economic nexus thresholds (usually $100,000 in sales or 200 transactions).
The Formula
Variables
- SA — Sale Amount — the pre-tax price charged to the customer
- SR — State Tax Rate — set by state legislature, ranges from 0% (OR, NH, MT, DE, AK) to 7.25% (CA)
- CR — County Rate — additional rate layered on top of state rate
- CiR — City Rate — municipal tax added in many cities
- Nexus — Legal obligation to collect tax — only collect if you have nexus in the customer's state
Worked Example
A customer in a county with 6% state, 1% county, and 0.5% city tax buys a $100 item. Combined rate = 7.5%. Tax = $7.50. Customer pays $107.50. If your store has no nexus in that state (e.g., you're a small seller under the economic threshold), no tax is required and the customer pays $100.
Practical Tips
- Economic nexus thresholds vary by state but most use $100,000/year in sales OR 200 transactions as the trigger.
- Use a tax automation tool like TaxJar or Avalara once you sell in 5+ states — manual calculation doesn't scale.
- Alaska, Delaware, Montana, New Hampshire, and Oregon have no state sales tax, though some local jurisdictions in Alaska do collect tax.
- Marketplace facilitators (Amazon, Etsy, eBay) collect and remit sales tax on your behalf for sales made on their platform — you generally don't need to worry about those.
- Keep records of all sales tax collected — you'll need to file returns in each nexus state, usually monthly or quarterly.
Frequently Asked Questions
What is economic nexus?
Economic nexus means you've made enough sales in a state to be required to collect tax there, even without a physical presence. After the 2018 South Dakota v. Wayfair Supreme Court ruling, most states set thresholds of $100,000 in annual sales or 200 transactions. Once you cross that threshold, you must register, collect, and remit sales tax in that state.
Do I collect tax based on where I am or where my customer is?
For ecommerce, most states use destination-based sourcing — tax is based on where the customer receives the goods, not where your business is located. A few states (like Arizona, Illinois, Missouri) use origin-based sourcing for intrastate sales, but destination-based is the rule for out-of-state sellers.
What products are exempt from sales tax?
Exemptions vary by state. Groceries are exempt or taxed at reduced rates in many states. Prescription drugs are widely exempt. Clothing is exempt in some northeastern states. Digital products and SaaS are increasingly taxed but rules vary widely. Always verify product-specific exemptions for each state you sell in.
How do I find the right tax rate for each customer?
Sales tax rates are extremely granular — there are over 12,000 tax jurisdictions in the US. The most practical approach is using a tax automation API (TaxJar, Avalara, Stripe Tax) that looks up the rate by customer address in real time. This calculator is useful for estimating; for live transactions, use an automated tool.
When do I need to register to collect sales tax in a state?
Register before you make your first taxable sale in a state where you have nexus. If you suddenly cross an economic nexus threshold mid-year, register promptly and begin collecting — some states allow a grace period, but retroactive liability is a real risk. Most state revenue departments have online registration portals.