Sales Tax Calculator

What it does

Compute sales tax from a pre-tax price, reverse-calculate the pre-tax subtotal from a receipt total, or compare rates across regions. Works with any rate — US state (0–7.25% state + up to 4% local for combined rates near 10% in places like California, Tennessee, Louisiana), Canadian GST/HST (5–15% depending on province), UK VAT (20% standard, 5% reduced, 0% exempt), EU VAT (17–27% depending on country), or any custom rate (Australian GST 10%, NZ GST 15%, Singapore GST 9%, etc.).

US sales tax is uniquely complex among developed countries: there’s no federal sales tax, so each state sets its own rate (Oregon, Montana, New Hampshire, Delaware, Alaska have zero state tax), and within most states, counties and cities add their own local rates. The combined rate that actually shows up on your receipt can vary by 2-3 percentage points across town lines. Online retailers must collect sales tax in any state where they have nexus (since the 2018 South Dakota v. Wayfair Supreme Court decision), which means most major retailers now collect tax everywhere — different from the pre-2018 era when out-of-state purchases were often tax-free.

Reverse calculation (pre-tax from total) is the most common practical use — you have a receipt total and need to know the pre-tax subtotal for expense reports, accounting, or splitting a check fairly. Math: pre-tax = total / (1 + tax rate). At 8.25% combined tax, a $100 receipt = $92.38 pre-tax, $7.62 tax. For business expense tracking, pre-tax is what counts toward deductions and budgets; the tax line is its own accounting entry.

How to use it

1. Pick mode: forward (price → total with tax) or reverse (total → pre-tax + tax breakdown).
2. Enter the price (pre-tax for forward mode, total for reverse mode).
3. Enter the tax rate as a percentage. For US: combined state + local (e.g., 8.25 for California). For VAT regions: standard rate (e.g., 20 for UK).
4. Read the breakdown: subtotal, tax amount, and total. Reverse mode shows what % of the total was tax.
5. For multi-region comparisons: re-run with different rates (e.g., compare Oregon 0% vs California 8.25% vs New York 8.875%) to see the cost difference on the same purchase.

When to use this tool

• Expense reports and bookkeeping — separating pre-tax cost (deductible) from sales tax (separate accounting line).
• Online shopping comparison across state lines — knowing whether to buy locally or order online with shipping.
• Setting prices as a small business — calculating the gross price needed to net a target after tax.
• Travel planning across borders — comparing combined VAT/GST rates to plan large purchases (electronics in tax-free Oregon vs taxed in California).

When not to use it

• Personal income tax — different tool entirely (use a tax bracket calculator instead).
• Use tax (when buying out-of-state and bringing into a taxing state) — those rules vary by state and require different forms.
• VAT recovery for business travel in EU — that requires invoices in specific format and goes through reclaim services, not just rate calculation.
• Sales tax NEXUS questions for online sellers — that's a legal/accounting issue, not a calculator question.

Common use cases

• Verifying a number or output before passing it on
• Quick calculation during a typical workday
• Pre-decision sanity-check on inputs and outputs
• Educational use — demonstrating the underlying concept