Sales Tax Total Calculator
Add sales tax to a purchase to get the total, or split a tax-inclusive total back into the pre-tax price and the tax.
How it works
Add: tax = price × rate% · Remove: price = total ÷ (1 + rate%)
To add tax you multiply the pre-tax price by the rate and add it on. To go the other way — recovering the pre-tax price from a receipt total — you divide by (1 + rate), not by subtracting the rate, because the tax was charged on the smaller base. That distinction matters for expense reports and bookkeeping, where you often need to separate the tax you paid from the item cost.
Worked example
On a $120 pre-tax purchase at 8.25%, tax is 120 × 0.0825 = $9.90 and the total is $129.90. Working backward from a $129.90 tax-included total: 129.90 ÷ 1.0825 = $120.00 pre-tax, confirming $9.90 of tax.
Frequently asked questions
How do I remove tax from a total?
Divide the total by 1 plus the rate as a decimal. For a $129.90 total at 8.25%, the pre-tax price is 129.90 ÷ 1.0825 = $120.00 — not 129.90 minus 8.25%.
Why can’t I just subtract the tax percentage?
Because the tax was calculated on the pre-tax price, a smaller base than the total. Subtracting the percentage from the total over-removes tax and understates the original price.
Where do I find my local rate?
US sales tax combines state, county and city rates, so it varies by exact address — commonly 6% to 10%. Check your state revenue department or a recent receipt for the precise combined rate.
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This calculator is for educational purposes. Double-check important results before acting on them.