Tax · Free tool
Self-Assessment Tax Calculator
Before filing ITR, you must pay any balance tax (after TDS + advance tax) along with interest under sections 234A (late filing) and 234B (advance tax shortfall).
What self-assessment tax actually is
Self-assessment tax (SAT) is the balance income tax you pay before filing your ITR, after netting off TDS (Form 26AS / AIS), TCS, and any advance tax instalments. If TDS + advance tax already covers your liability you owe nothing extra; if not, you pay the gap as SAT via challan ITNS 280 (code 300) on the income tax e-filing portal. The ITR can't be filed until SAT is paid.
Worked example
Total tax liability for FY 2024-25 is ₹2,40,000. Employer deducted ₹1,80,000 TDS and you paid ₹40,000 advance tax in Q3. The shortfall is ₹20,000 — that's your SAT. If you file on 31 July 2025, no 234A interest applies (no delay), but 234B kicks in because advance tax was less than 90% of liability — roughly 1% per month × 4 months × ₹20,000 = ₹800additional. Pay ₹20,800 via challan 280 before filing.
When to use this
- Got a big year-end bonus, RSU vest or capital gain not covered by TDS
- Filed late (after 31 July) — need to add 234A interest
- Advance tax instalments fell short of the 15/45/75/100% quarterly schedule
- Freelancers without TDS who didn't pay advance tax
Use the advance tax calculator next year to avoid the interest entirely, and reconcile your TDS with Form 26AS reader before computing the shortfall.
FAQ
When is self-assessment tax due?
Before filing the ITR. The ITR portal will not let you submit if there's an outstanding balance. Pay via Challan ITNS-280 (BSR + challan number gets auto-imported into your ITR).
Is interest under 234A still charged if I pay before filing?
Yes — 234A is for late *filing*, not late payment. If you file after Jul 31 (the original due date for individuals), 234A interest at 1%/month accrues on the balance until you actually file.
Can self-assessment tax be paid by credit card?
Yes via the e-pay tax portal (income tax e-filing site). UPI, debit card, net banking and credit card are all options. Card payments may attract a small convenience fee (~0.5-1%).