🧾 Sales Tax Calculator

Enter a price and convert between tax-included and tax-excluded amounts. Supports 10%, 8% reduced rate, and custom rates. Batch mode, currency symbols, thousands separators, and rounding modes (floor / ceil / round).

100% Free No signup Browser-only 5 languages Dark mode

🔒 About Privacy

・All calculations happen entirely in your browser
・Price data is never sent to any server
・No storage logs, no upload history, no database

Input Mode

Tax Rate

Custom Rate (%)

Currency

Rounding

Prices (one per line, batch supported)

Breakdown

📖 Where people get stuck

Convert between tax-inclusive and tax-exclusive prices in either direction, at 10 %, the reduced 8 %, or any rate you enter. Everything runs in the browser. What you get is the figure for a single line. The tax on a whole invoice differs by a few units depending on whether you compute per line and sum, or compute once on the total — and which is correct is set by regulation and by agreement with the other party, not by arithmetic.

Case	What happens	What to do
Rounding leaves you a unit out	Whether the fractional part of the tax is truncated, rounded up or rounded to nearest is not fixed in law — the business chooses and is expected to apply the same method consistently. That is why your invoice and the customer figure can differ by one unit with neither party being wrong. Accounting software most often defaults to truncation, but there is no universal setting.	Agree the method at the start of the relationship and put it in writing. In the system, hold the rounding method as configuration rather than hard-coding it, because it can differ per counterparty. In tests, always include the boundary values that land on a half unit — 105 at 10 % gives 10.5 — since that is the only place a change in implementation shows up.
Going back from a tax-inclusive price does not return the original	A tax-exclusive 1,000 becomes 1,100 inclusive and returns to 1,000. But an inclusive 1,000 becomes 909 exclusive and comes back as 999: the remainder lost in the division does not reappear in the multiplication. Where the inclusive price is the authoritative one, the exclusive figure is always a derived display value, never the source of truth.	Store exactly one authoritative amount and compute the other at display time. Store both and sooner or later only one of them gets updated. Retail, where the inclusive price is what customers see, stores inclusive; business-to-business, where quotes are exclusive, stores exclusive. It also matters that you never feed a rounded value into further arithmetic — summing display-rounded amounts is how a total stops matching its own line items.
Getting the reduced rate wrong	The 8 % rate covers food and drink excluding alcohol and eating out, and newspapers on a subscription published at least twice a week. The classification is often counter-intuitive: eating in is 10 %, taking away is 8 %; a cooking wine that qualifies as alcohol is 10 % while a non-alcoholic seasoning version is 8 %. Whether it is takeaway is determined by asking the customer at the point of order, not by any property of the product.	Hold the rate as an attribute of the product master and allow it to be overridden at order time; fixing it per product cannot handle a shop serving both eat-in and takeaway. Give the rate itself an effective-from date so that recalculating an old transaction uses the rate that applied then. That is what stops a reissued past invoice coming out at today rate.

Rates and tax systems differ by country and change over time. You can type any rate here, so it works for VAT elsewhere, but the rules for multiple rates, what is exempt or reduced, and the conventions for rounding are entirely national. For cross-border transactions such as supplying a digital service, the rate of the buyer country increasingly applies, so computing with your own rate alone is not enough. Where the numbers affect the business, confirm with an accountant — this page does the arithmetic and makes none of the judgements.

📖 How to Use

1

Choose input mode

Select whether your input is tax-included or tax-excluded.
2

Choose tax rate

Pick 10%, 8% reduced, or a custom rate.
3

Enter prices

One price per line for batch conversion.
4

Check breakdown

See subtotal, tax amount, and total per row plus grand totals. Copy results to clipboard.

❓ Frequently Asked Questions

When does the 8% reduced rate apply?

In Japan, the 8% reduced rate applies to food and beverages (excluding alcohol and dine-in) and to subscription newspapers published twice or more per week. Check the National Tax Agency for details.

Which rounding mode should I choose?

Round-half-up is the most common in Japanese retail, but some companies use floor or ceil. Choose the mode that matches your accounting rules.

Is my input data stored?

No. All calculations run entirely in your browser (JavaScript). Price data never leaves your device.

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