Section 234 Interest Calculator — 234A, 234B, 234C
Updated June 2026 · VerifiedCalculate Section 234 Interest Online
Enter your tax details below to calculate interest under Sections 234A, 234B, and 234C of the Income-tax Act, 2025.
What Is Section 234A Interest (Late Filing)?
Section 234A charges interest when an ITR is filed after the due date. The interest is calculated at 1% per month (or part of a month) on the unpaid tax (total tax minus TDS/TCS and advance tax paid).
- Period: From the day after the due date to the actual date of filing.
- Basis: Net tax payable after deducting TDS, TCS, and advance tax.
- Part-month rule: Even one day in a month counts as a full month.
What Is Section 234B Interest (Advance Tax Shortfall)?
Section 234B applies when advance tax paid is less than 90% of the assessed tax. Interest at 1% per month is charged on the shortfall.
- Assessed tax: Total tax minus TDS/TCS (excluding self-assessment tax).
- Trigger: If advance tax paid is less than 90% of assessed tax.
- Period: From 1st April of the Tax Year to the date of determination (filing or assessment).
- Basis: Assessed tax minus advance tax paid.
What Is Section 234C Interest (Deferment)?
Section 234C charges interest when advance tax instalments are not paid on time or fall short of the prescribed percentages.
| Instalment Due Date | Cumulative % Due | Interest Period |
|---|---|---|
| 15th June | 15% of advance tax | 3 months |
| 15th September | 45% of advance tax | 3 months |
| 15th December | 75% of advance tax | 3 months |
| 15th March | 100% of advance tax | 1 month |
Frequently Asked Questions
Is Section 234 interest calculated as simple or compound interest?
Section 234A, 234B, and 234C interest is calculated as simple interest at 1% per month. There is no compounding.
Can Section 234 interest be waived?
Interest under Section 234A, 234B, and 234C is mandatory and cannot be waived by the Assessing Officer. It is automatically computed during ITR processing.
Does a part month count as a full month for 234 interest?
Yes. Even if the delay is by a single day, that part of the month is treated as a full month for interest calculation purposes.
Is advance tax required if total tax is below ₹10,000?
No. If the total tax liability after TDS/TCS is less than ₹10,000, advance tax is not required. Consequently, Section 234B and 234C interest will not apply.
Are Sections 234A, 234B, 234C still the same under the Income-tax Act, 2025?
Yes. Sections 234A, 234B, and 234C continue under the Income-tax Act, 2025 with the same numbering, rates (1% per month), and calculation methodology as under the repealed 1961 Act.