Sales Tax & VAT Calculator
Add tax to a net price or back the tax out of a tax-inclusive price. Shows net, tax, and gross side by side with common country rate presets and line totals.
Net (excl. tax)
$100.00
Tax amount
$10.00
Gross (incl. tax)
$110.00
$100.00 × (1 + 10 ÷ 100). Tax is 9.09% of the gross price.Adding tax versus extracting it
These are two different calculations and swapping them is the most common tax arithmetic error. If a price excludes tax, you multiply. If it includes tax, you divide.
With a 20% rate, a net price of 100 becomes 100 × 1.20 = 120. Going the other way, a gross price of 120 has a net of 120 ÷ 1.20 = 100 and 20 of tax. Subtracting 20% from 120 gives 96 — a wrong answer produced by applying the rate to the wrong base.
Note: the tax portion of a gross price is always a smaller share than the rate itself. At a 20% rate, tax is 20% of the net but only 16.67% of the gross.
Sales tax, VAT, and GST are not the same thing
The arithmetic is identical, but the systems behind them differ in who collects and when.
- Sales tax: charged once, at the final retail sale. Used in the United States, set at state and local level, and usually shown added at the register rather than in the shelf price.
- VAT (Value Added Tax): collected at every stage of production, with businesses reclaiming the tax they paid on inputs. Standard across the EU and UK. Consumer prices are normally quoted tax-inclusive.
- GST (Goods and Services Tax): functionally a VAT under a different name, used in Australia, Canada, India, and elsewhere. Canada layers provincial taxes on top, producing combined HST rates.
The practical consequence for a shopper: in a VAT country the displayed price is what you pay, while in the US the register total will exceed the shelf price.
Common standard rates
Standard rates for reference only. Reduced rates frequently apply to food, books, medicine, and transport, and local surcharges can change the effective figure.
| Region | System | Standard rate | Shown in price? |
|---|---|---|---|
| United States | Sales tax | 0–10% (varies locally) | No |
| United Kingdom | VAT | 20% | Yes |
| Germany | VAT | 19% | Yes |
| South Korea | VAT | 10% | Yes |
| Japan | Consumption tax | 10% (8% reduced) | Yes |
| Australia | GST | 10% | Yes |
| Canada | GST + provincial | 5% federal, 5–15% combined | No |
Rounding and invoice totals
Tax on a multi-line invoice can be computed per line and summed, or computed once on the subtotal. The two approaches can differ by a cent or two because each rounding step discards a fraction. Tax authorities generally specify which method is acceptable, and accounting software follows a fixed convention so totals reconcile.
This calculator rounds only for display and computes on unrounded values, so a quantity line total matches the per-unit figure multiplied out. For filing or invoicing, follow your jurisdiction’s stated rounding rule rather than a general-purpose calculator.
Scope and limitations
This tool applies a single flat rate. It does not model combined federal and provincial taxes, reduced or zero rates by product category, exemptions, thresholds for small suppliers, reverse-charge rules on cross-border services, or digital services rules that tax by customer location.
Use it for quick estimates and for checking a receipt. For tax filing, registration decisions, or cross-border sales, confirm the applicable rate and treatment with your tax authority or an accountant.