Practical GST calculations

GST calculators that show the working.

Use the inputs, see the result, then read the assumptions and statutory basis immediately below it. These tools run in your browser and do not send what you enter anywhere.

Legal basis reviewed for this calculator set: 12 September 2026

Check the inputs and the applicable law before relying on a result. These calculators are working aids. Extensions, amnesty schemes, part payments, period-specific notifications and facts outside the inputs can change the result.

Three tools

Calculate a GST figure

Choose the calculation that matches the question you are trying to answer.

1.1 Late fee and interest on a delayed GSTR-3B

Legal basis: Section 47(1), Section 50(1), Rule 88B and the period-specific late-fee notifications reflected in the calculator. Review date: 12 September 2026.

Delayed return

Interest is charged on the cash portion only, per Rule 88B(1).

Due date of the return

Date the return was furnished

Tax discharged in cash (₹)

Interest rate (% per annum)

Aggregate turnover, preceding year

Tax period

Days of delay

Interest u/s 50(1)

₹0

Late fee u/s 47(1)

₹0

Enter the dates above.

Delayed GSTR-3B working paper

Inputs will appear here after the calculation runs.

1.2 Interest on credit wrongly availed

Legal basis: Section 50(3), Rule 88B(3) and the applicable historical rate position. Review date: 12 September 2026.

Section 50(3) with Rule 88B(3)

Interest runs only where the credit was utilised, and only for the period it stayed utilised.

Credit wrongly availed and utilised (₹)

Interest rate (% per annum)

Utilised from

Reversed or paid on

Days

Interest

₹0

Total with tax

₹0

Credit taken and reversed without being utilised attracts no interest. Rule 88B(3). The rate was 24% until Section 50(3) was substituted with retrospective effect from 01.07.2017; see the history below.

Section 50(3) ITC interest working paper

Inputs will appear here after the calculation runs.

1.3 Limitation, the last date for a notice or an order

Legal basis: Sections 73, 74 and 74A, with the annual-return due date and selected extended positions reflected in the calculator. Review date: 12 September 2026.

Sections 73, 74 and 74A

Counted from the due date of the annual return for the financial year.

Financial year

Provision

Annual return due

Notice by

Order by

Choose a year and provision. For Section 74A, enter the actual SCN date to calculate the 12-month order deadline.

Limitation working paper

Inputs will appear here after the calculation runs.

Estimates, and nothing more. The first assumes an ordinary due date with no notified extension, delay counted in whole days, and interest on the whole cash amount for the whole period. None of the three accounts for part payments, amnesty schemes, or amounts already declared at Table 5.1 of the return.