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How to use
This calculator works with a tax rate you provide. Start from a pre-tax subtotal to add tax, start from a tax-inclusive total to reverse the tax, or enter subtotal and total to recover the effective percentage between them.
- Choose add tax, remove tax, or find the rate.
- Enter the amount and rate, or enter subtotal and total when solving for the rate.
- Review the pre-tax subtotal, tax amount, final total and effective rate.
How it is calculated
Example
Example: a 100 subtotal at 8.25% produces 8.25 tax and a 108.25 total. Starting from 108.25 as tax-inclusive with the same rate reverses to a 100 pre-tax subtotal. To remove an assumed 8% tax from a total of 216, choose Remove tax: subtotal =216/1.08=200 and tax =16. Subtracting 8% of 216 instead gives 198.72, which is a different calculation. Choose Find the rate with subtotal 200 and total 216 to recover 8%; this is a hypothetical rate.
Important notes
This calculator does not determine the legally applicable rate or whether an item is taxable. Use the official rate for the transaction and jurisdiction. Compound taxes, exemptions, thresholds or fixed fees may need a different calculation. Mihsaba keeps VAT as a separate calculator intent.
Worked examples and interpreting results
To add 15% sales tax to a pre-tax subtotal of 100, multiply by 0.15 and add the tax to the subtotal. The rate is illustrative, not a local tax determination.
| Case | Calculation | Result |
|---|---|---|
| Tax amount | 100 × 15 ÷ 100 | 15 |
| Total including tax | 100 + 15 | 115 |
| Reverse 15% tax from 115 | 115 ÷ 1.15 | 100 |
How to check the result
First identify whether the input amount already includes tax. Sales tax rates and exemptions vary by location and product, and the example is not tax advice.
Frequently asked questions
How do I remove tax from a tax-inclusive total?
Divide the total by 1 plus the tax rate as a decimal, then subtract the recovered subtotal from the total.
Does this calculator look up my local rate?
No. Enter the official combined rate that applies to your transaction.
Is sales tax the same as VAT?
The percentage arithmetic can be similar, but legal treatment and search intent differ, so Mihsaba keeps them as separate tools.
Why can’t I subtract the tax percentage directly from the total?
The rate applies to the pre-tax subtotal. Tax inside a total is total×rate/(100+rate), when rate is entered as a percentage number.
How do I calculate the tax rate from subtotal and total?
Use (total/subtotal−1)×100 with a positive subtotal. Total 216 and subtotal 200 give 8%. This arithmetic does not establish the legally applicable rate.