Business Finance
GST Inclusive & Exclusive Calculator
Add GST to a base amount or extract it from an inclusive total using a rate you enter. Compare invoice arithmetic and export results locally; no slab lookup.
- 1Set your baseline
- 2Change one assumption
- 3Compare and save
Scenario assumptions
Calculate inclusive or exclusive invoice arithmetic using a rate you enter. Verify the applicable rate and eligibility separately.
Values are not converted between currencies.
Enter assumptions, then compare both scenarios.
Your scenario results
Calculate both scenarios to see the comparison and a visual explanation.
See the effect of your assumptions
Enter both scenarios and select Compare scenarios. Validated results and visuals appear together.
An exclusive amount of 1,000 at an entered rate of 18% gives tax of 180 and a total of 1,180.
Save and resume locally
Scenario JSON saves names, inputs, currency and conventions for this tool. Import it to resume. Results JSON records the calculation and is not an import format. No automatic saving occurs.
Worked example and interpretation
An exclusive amount of 1,000 at an entered rate of 18% gives tax of 180 and a total of 1,180. Reset restores this example in both scenarios. Other calculation modes use the retained example assumptions.
These deterministic illustrations do not establish credit eligibility, investment performance, statutory compliance or final lender terms. Inspect the formulas and timing conventions before using a result in a decision.
Calculations and scenario files stay in your browser. Financial inputs are not added to navigation links, automatically stored or transmitted by this tool. Downloaded files contain your entered information.
What are the base, tax and total when the entered invoice amount includes or excludes GST?
- Enter the invoice amount and a verified tax rate. Choose whether the amount already includes tax.
- Compare scenarios and check that base plus tax equals the total under the chosen convention.
- Export the arithmetic if useful. Confirm eligibility, rate selection and invoice rounding against the applicable requirements separately.
A worked example
An exclusive amount of 1,000 at an entered rate of 18% gives tax of 180 and a total of 1,180. Starting with an inclusive total of 1,180 at the same rate recovers a base of 1,000 and tax of 180.
Common questions
How do inclusive and exclusive amounts differ?
For an exclusive amount, tax is base multiplied by the entered rate and total is base plus tax. For an inclusive total, base is total divided by one plus the rate; tax is the difference between total and base.
Does this choose the GST rate or split tax components?
No. The tool uses the rate you enter and shows one combined tax amount. It does not supply slabs, determine place of supply, split CGST/SGST/IGST or establish tax eligibility.
How are amounts rounded?
The engine calculates at full precision. Displayed results use up to six decimal places, and results exports retain calculation precision. Apply the invoice rounding required for your own workflow separately.
Explore another calculation when you need it
Return to the free tools catalogue for calculators and browser utilities. Invoice inputs are not included in navigation links or automatically sent elsewhere.
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