Guide · Sales tax

How to use a sales tax calculator

Educational guide · Updated · About 4 min read

  1. Choose add tax (pretax known) or reverse (total with tax known).
  2. Enter the amount and tax percent (or use a rate preset).
  3. Optional: set quantity for multi-unit totals.
  4. Read pretax, tax, total, and the rate comparison table.

Example: $100 · 8% add tax

What it is not

  • Not a ZIP-code or city tax rate lookup
  • Not legal advice on taxable goods
  • Not a guarantee of register rounding

How we calculate · Questions

Frequently asked questions

What inputs do I need?

An amount (pretax or total), a tax percent, and optional quantity. Choose add or reverse mode.

Can I share a prefilled link?

Yes—use amount, tax, mode, and qty query parameters.

Related tool

Open the free sales tax calculator

Add tax or reverse total.

Open sales tax calculator

Sources linked above include U.S. government materials (for example CFPB, FDIC, NCUA, BLS, IRS) where noted. Sample math uses only labeled Nestfigure assumptions—not bank quotes, job offers, or personalized advice. Last reviewed: August 9, 2026.

YMYL notice: This site is for education only. It is not financial, tax, or investment advice. Nestfigure is not a bank, credit union, broker, investment adviser, or fiduciary. Product terms, rates, and penalties vary—always read your institution’s disclosures before acting. Calculator results are mathematical estimates, not bank quotes.