ITR-U Calculator: What an Updated Return Costs, and What Waiting Costs
The Section 140B slab is fixed by the date you actually file — and it steps up every 31 March. Most calculators tell you what you owe today. This one also tells you the exact date your bill jumps, how many days you have left, and what the delay will cost you in rupees.
What an ITR-U actually costs
There are four components, and they are not all in the same basket:
- Tax on the additional income, at that year’s rates, less the TDS, TCS and advance tax already credited against it.
- Interest under Sections 234A, 234B and 234C on the shortfall. This is the part that grows every single month you wait.
- Additional tax under Section 140B — 25%, 50%, 60% or 70% of the aggregate of tax and interest, depending purely on when you file.
- Late fee under Section 234F, where no return was filed at all — ₹5,000, or ₹1,000 if total income is within ₹5 lakh. Note that the fee sits outside the 140B base: it is a fee, not interest, so the slab is not charged on it.
The 48-month window, and which years are still open
The Finance Act 2025 doubled the window from 24 months to 48 months from the end of the relevant assessment year. Because every boundary is a 31 March, the position as things stand is:
| Assessment Year | Income year | Slab right now | Window closes |
|---|---|---|---|
| AY 2022-23 | FY 2021-22 | 70% — the top slab | 31 March 2027 |
| AY 2023-24 | FY 2022-23 | 60% | 31 March 2028 |
| AY 2024-25 | FY 2023-24 | 50% | 31 March 2029 |
| AY 2025-26 | FY 2024-25 | 25% — the cheapest slab | 31 March 2030 |
AY 2021-22 closed on 31 March 2026 and cannot be updated at all. AY 2022-23 is in the 70% slab and expires first — if that is your year, the arithmetic only gets worse from here.
When ITR-U is not available
An updated return is a one-way street: it can only increase what you owe. You cannot file one where it would reduce your tax, create or increase a refund, or where a search under Section 132, a survey under Section 133A or a prosecution has been initiated for that year. Only one updated return is permitted per assessment year.
One bar is easy to miss: no ITR-U may be furnished where a show-cause notice under Section 148A has been issued after 36 months from the end of the relevant assessment year. That bar lifts only if an order under Section 148A(3) holds that the case is not fit for a Section 148 notice.
Good to know
Interest runs on two clocks
Section 234B runs from 1 April of the assessment year and Section 234A from the day after the filing due date — both at 1% per month or part of a month. Where you filed nothing, roughly 2% a month accrues before the 140B slab is even applied.
Pay the challan before you file
The updated return must be accompanied by proof of payment. An ITR-U filed without the tax paid is defective, and an unverified one is treated as never filed — which can push you past a boundary you thought you had met.
The fee is not in the slab
Section 140B charges the slab on the aggregate of tax and interest. The Section 234F late fee is a fee, so it is payable but is not multiplied by 25% to 70%. Several calculators get this wrong and overstate the bill.
Related tools
Check the underlying liability with the Advance Tax Calculator, compare regimes in the Salary Tax Optimiser, or read the full ITR-U guide.
Frequently asked questions
How is the ITR-U additional tax calculated?
Section 140B charges 25%, 50%, 60% or 70% of the aggregate of tax and interest payable, depending on whether the updated return is filed within 12, 24, 36 or 48 months of the end of the relevant assessment year. Tax here includes surcharge and cess. The Section 234F late fee is not part of that base.
Which assessment years can I file an ITR-U for right now?
AY 2022-23 through AY 2025-26. AY 2021-22 closed on 31 March 2026. AY 2022-23 is in the 70% slab and closes on 31 March 2027, so it is the most urgent of the open years.
Does the slab depend on when I file or when I pay?
On the date the updated return is furnished, with the tax paid. Filing on 1 April rather than 31 March moves you into the next slab entirely, which is why the boundary matters far more than people expect.
Can I file an ITR-U to claim a refund?
No. An updated return cannot reduce your tax liability, cannot create or increase a refund, and cannot be used to increase a declared loss. It can only result in additional tax payable.
Can I file an ITR-U after receiving a Section 148 notice?
Yes, following the Finance Act 2026. An updated return may be furnished in pursuance of a Section 148 notice within the time specified in it, on payment of a further 10% under Section 140B(3A), making the effective rates 35%, 60%, 70% and 80%. Income covered by that payment is excluded from the Section 270A penalty computation.
Is the Section 234F late fee charged on top?
Yes, where no return was filed for that year. It is 5,000 rupees, reduced to 1,000 rupees where total income is within 5 lakh rupees. It is payable in addition, but the 140B slab is not applied to it.
How many times can I file an updated return?
Only once per assessment year. That makes accuracy more important than speed, but the slab still rewards filing before the next 31 March boundary.
Is this ITR-U calculator free?
Yes, completely free with no sign-up, and nothing you type is sent anywhere because the whole calculation runs in your browser.
Disclaimer: This tool is for general information and educational purposes only and is not tax advice. It applies Section 139(8A) and Section 140B of the Income-tax Act, 1961 as amended by the Finance Act 2025 and the Finance Act 2026, and computes interest under Sections 234A, 234B and 234C at 1% per month or part of a month on a simplified basis. Tax on the additional income is estimated at the marginal rate you select; it does not compute slab tax, rebates, Chapter VI-A deductions, relief under Sections 89, 90, 90A or 91, or MAT and AMT credits, and Section 234C assumes no advance tax was paid on this income unless you say otherwise. Your actual figures on the e-filing portal may differ. Confirm the final computation with a chartered accountant before you pay and file. © TaxSlabs.
