Reverse GST Calculator
Work out reverse gst instantly with clear inputs, formula shown and shareable results.
About Reverse GST Calculator
Working backwards from an invoice total and the tax charged recovers both the taxable value and the rate actually applied. Comparing the implied rate against standard slabs is a quick check for invoicing errors.
Formula
Reverse rate
Taxable value = total - tax; implied rate = tax / taxable value × 100
Worked example
With the default values below, Reverse GST Calculator returns Implied Tax Rate of 18.000%. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Total Amount Paidminimum 0
- 47,200
- Tax Shown On The Invoiceminimum 0
- 7,200
Results
- Implied Tax Rate
- 18.000%
- Taxable Value
- $40,000.00
- Tax As Share Of Total Paid
- 15.254%
- Nearest Standard Rate Slab
- 18.00%
Step by step
- 1Values used
- 2Reverse rate
- 3Implied Tax Rate= 18.000
- 4Taxable Value= 40,000.00
- 5Tax As Share Of Total Paid= 15.254
- 6Nearest Standard Rate Slab= 18.00
Assumptions and limits
- The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
- Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- Tax figures are estimates based on the rates, caps and thresholds you enter. Real rules differ by jurisdiction and change every year, and personal circumstances alter the outcome. This is not tax or financial advice — confirm with a qualified adviser.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Tax figures are estimates based on the rates, caps and thresholds you enter. Real rules differ by jurisdiction and change every year, and personal circumstances alter the outcome. This is not tax or financial advice — confirm with a qualified adviser.
Frequently Asked Questions
Why check the implied rate?
Because a rate that matches no slab usually signals an error, a mixed supply or an undisclosed cess.
What if the invoice shows components separately?
Add them together as the total tax before computing the implied rate.