Sales Tax Calculator
Use the same page for add-tax, reverse-tax, and implied-rate calculations with shareable URL state from day one.
Sales Tax Breakdown
Calculation Steps
How the Sales Tax Modes Work
Each mode solves the same tax relationship from a different starting point, so you do not need separate tools.
Add tax from a subtotal
Start with the before-tax price and a known rate.
Tax = subtotal × rate. Total with tax = subtotal + tax.
Remove tax from a total
Start with the final amount paid and the known rate.
Subtotal = total ÷ (1 + rate). Tax = total - subtotal.
Find the implied tax rate
Start with the before-tax subtotal and the final total.
Tax = total - subtotal. Rate = tax ÷ subtotal.
Sales Tax FAQ
Common assumptions and edge cases for the first sales-tax release.
Does this calculator look up state or local sales tax rates?
No. Enter the combined rate you want to model. This first version keeps rate handling explicit instead of depending on a jurisdiction dataset.
Can I use a zero percent tax rate?
Yes. A zero rate is valid when a purchase is tax-exempt or when the total already equals the before-tax price.
Can I use this for VAT or GST calculations?
The percentage math is the same for a simple add-on tax, but this page is written for straightforward sales-tax scenarios rather than jurisdiction-specific VAT or GST rules.