Sales Tax Calculator: Find Sales Tax, Rate & Total

Two directions, one rate. Add tax: sales tax = pre-tax price × rate ÷ 100, total = pre-tax price + tax. Remove tax (reverse sales tax): pre-tax price = tax-inclusive total ÷ (1 + rate ÷ 100), tax = total − pre-tax price — division, not subtraction, because the tax was charged on the smaller pre-tax base. Money is rounded once, to the nearest cent, half-away-from-zero, with binary-drift snapping so no output can ever read 8.2499999997; the displayed pre-tax price, tax and total always reconcile exactly. Rates come from one of three clearly labelled sources, and the label the user sees is derived from a single precision field, never from copy written next to a form control: MANUAL — the rate you type, exact for that rate; STATE AVERAGE — the population-weighted average combined state + local rate for a state, from the cited dated snapshot, which is an average and not the rate at any specific address; EXACT LOCATION — address or ZIP resolution, which requires a production rate provider behind a server boundary. No such provider is connected to this site, so that option is shown as unavailable and the tool degrades deterministically to the state average; nothing here is a real-time feed, a ZIP-level lookup or an address-level determination. When a rate cannot be resolved the tool shows 'Rate unavailable' and asks for a manual rate — it never falls back to 0%. Taxability is not modelled: the full purchase amount is treated as taxable because no verified per-state taxability rule set is bound to this page. RELIABILITY: exact for a documented rate and price; less reliable when local rates differ from the state average, when the taxable base differs from the purchase price (groceries, clothing and prescription drugs are treated differently by state), when rates change mid-year, and for vehicle purchases, where trade-ins, rebates and registration rules change the taxable base.

Reviewed according to the CalcDomain Editorial Policy & Calculator Methodology. We document formulas, edge cases, sources, update dates, and correction paths for calculator pages.

Rounding policy

• Internal precision: amounts and rates are carried as double-precision numbers; rates are normalised to 4 decimal places.
• Tax rounding: the sales tax is rounded once, to the nearest cent, half-away-from-zero. A value within one-millionth of a cent of an exact cent is snapped to it first, so floating-point drift never changes a result.
• Reconciliation: in add mode the total is the pre-tax price plus the rounded tax; in remove mode the tax is the total minus the rounded pre-tax price. The three figures shown always add up exactly.
• Display: results are already cent-exact — formatting only pads to two decimals, it never re-rounds.
• Baskets: each line is rounded to the cent and then summed (the U.S. point-of-sale convention), so the line items always reconcile with the grand total.

How the rate is sourced

Two datasets drive what the page shows. The Tax Foundation 'State and Local Sales Tax Rates, 2026' per-state table (snapshot as of January 1, 2026) supplies the statutory state rate, the population-weighted average local rate and the average combined rate behind the state selector and the reference table; the same publication supplies the 7.53% national average. The Federation of Tax Administrators holiday dataset drives the secondary holiday planner. Both are dated snapshots, not live feeds, and neither is an address-level rate source.

No sales tax rate provider is connected to this site, so address and ZIP lookup are unavailable. State average and manual rate remain fully operational.

Taxability: Taxability not determined — this calculation assumes the full purchase amount is taxable. No category on this page is treated as exempt, because no verified per-state taxability rule set is bound to it.

Assumptions

• The rate used is the combined state + local rate actually charged at the point of sale. The state selector supplies a dated statewide average as a starting point, not an address-level determination.
• The full amount entered is taxable: no exemptions, tax holidays or reduced rates are applied to any part of it.
• In remove mode, the entered total includes sales tax at exactly the entered rate and nothing else — no tips, service charges, deposits or excise fees.
• Rates are snapshots from the cited source as of the date shown on the page; nothing here updates in real time.

Limitations

• This is not a ZIP-code or address-level rate lookup. No rate provider is connected to this site, so city, county and special-district rates must be entered manually when they differ from the state average.
• Historical rates are not looked up. A purchase date before the snapshot date produces a warning rather than a substituted rate.
• Exemptions and reduced rates are not modelled — groceries, clothing, prescription drugs, digital goods and services are treated differently by state, so the taxable base can be smaller than the purchase total.
• Vehicle purchases are out of scope: trade-in credits, rebates, documentation fees and registration rules change the taxable base and vary by state.
• Mid-year local rate changes are not reflected until the cited dataset snapshot is refreshed and re-verified.
• Origin- vs destination-based sourcing rules for online and cross-border sales can change which jurisdiction's rate applies. Verify against your state revenue department before using a figure for compliance.

Review

Editorial review: Ugo Candido, Founder & Editor-in-Chief (August 8, 2026). Technical review: contract-gated golden tests, engine unit tests, data-integrity tests and render tests on each build — these are automated regression tests, not a review by an external tax professional. External professional review: human review completed 2026-08-08 by the site owner, covering the Tax Foundation rate table and the source-native precision of the statutory state rates; no external tax professional has reviewed the page.

Version history

• 2026-08-08 · v4.1 — Human verification completed: the Tax Foundation "State and Local Sales Tax Rates, 2026" table was reviewed and approved, so the rate dataset is now verified:true with a named sign-off and the verification firewall allows the page to be indexed. Statutory rates published at sub-percent precision (Missouri 4.225%, Minnesota 6.875%, New Jersey 6.625%, New Mexico 4.875%) are carried unrounded through the data, the calculations and now the display — the state table, the state selector and the holiday planner prefill previously rounded them to two decimals, and the holiday prefill fed that rounded value back into its own arithmetic. Also tightened the wording about Delaware, Montana, New Hampshire and Oregon: the page now says they have a 0% statewide rate and no general local sales tax included in this dataset, which is what the data supports, rather than making a broader claim about every level of taxation. Published under Finance > More Calculators.
• 2026-08-08 · v4.0 — Rebuilt as a general sales tax calculator first: add/remove modes above the fold, three labelled rate sources (exact location, state estimate, manual), a precision badge and provenance block on every result, a rate component breakdown shown only when the data contains one, a multiple-item basket with CSV export, and PII-free result sharing. New pure computation layer (engine/lib/sales-tax-engine.js) with a documented cent-rounding policy, and a rate-resolution interface (engine/lib/sales-tax-rate-resolver.js) separate from the arithmetic. The holiday planner moved below the core content as a secondary tool. The state rate table was re-retrieved from the cited publication and is now server-rendered from the dataset; 20 of 51 rows had drifted from the source, including a Louisiana statutory rate that predated the 2025 increase. The page stays noindex until a human signs off on the refreshed rate data.
• 2026-07-24 · v3.0 — Added the Sales Tax Holiday Savings Planner as the primary tab, powered by two new datasets (10 holidays, 51 rate jurisdictions). Basic add/remove calculator retained as a secondary tab.
• 2026-07-09 · v2.1 — Source hygiene: removed an unrelated price-index dataset from Data Sources and harmonized all date labels to the Tax Foundation snapshot as of January 1, 2026.
• 2026-07-09 · v2.0 — Added remove-tax mode (back out the pre-tax price from a tax-included total by dividing by 1 + rate), pre-tax amount output, and explicit methodology on state averages vs manual exact rates.
• 2026-05-17 · v1.0 — Initial release: add sales tax to a pre-tax amount using the state-average rate selector.

Page updated August 8, 2026 · Rate data as of 2026-01-01 · rate data verified yes

CalcDomain publishes calculation tools and reference data. Nothing on this page is tax or legal advice, and it is not a tax determination for filing, invoicing or collection.