Verified April 2026

Reverse Sales Tax Calculator

Separate sales tax from a total receipt amount with a fast reverse calculator, state base rates, and worked examples for receipts, refunds, and audits.

Open calculator ZIP code lookup

Receipt math

Work backward from the total paid

Enter the final receipt amount and combined sales tax rate to estimate the original subtotal and tax collected. This is useful for receipts, reimbursement checks, audits, and refund reviews.

Total Amount Paid

Sales Tax Rate

Or load a state base rate

Pre-tax price

$0.00

Sales tax amount

$0.00

Tax share of total

0.00%

Formula

Reverse sales tax equation

Pre-tax price = Total paid / (1 + tax rate as a decimal)

Example: a total of $108.50 at an 8.500% tax rate becomes $108.50 / 1.085 = $100.00 pre-tax. The tax portion is $8.50.

Best use cases

Receipts

Split item subtotal from a final paid amount when only the grand total appears on the receipt.

Refund reviews

Check whether a store or marketplace refunded the correct amount of tax.

Audit prep

Validate invoices, credit memos, and tax-inclusive purchase records before filing.

Keyword coverage

sales tax rate sales tax calculator sales tax by zip code sales tax lookup sales tax breakdown combined sales tax rate state sales tax county sales tax city sales tax special district tax