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Advance tax follows a 15%, 45%, 75%, 100% cumulative schedule across 15 June, 15 September, 15 December, and 15 March. Shortfalls trigger Section 234C interest at 1% per month; Challan 280 paid under the wrong PAN or wrong AY lands in the wrong Form 26AS and compounds Section 234B interest.
Match each Challan 280 payment to its CIN (BSR code + date + serial) in Form 26AS Part F after a 3–7 day lag. Validate cumulative payment against the scheduled 15/45/75/100 percentages, and reconcile any shortfall before the next instalment to stop Section 234C interest growing. Catch wrong PAN or wrong AY entries in the same cycle and raise a correction request.
CIN-keyed matching to Form 26AS Part F, cumulative instalment schedule, Section 234B/234C interest calculator, and challan-correction workflow for wrong PAN/AY entries.
Fully credited advance tax in Form 26AS, zero avoidable 234B/234C interest, clean Challan 280 audit trail, and reconciled tax expense in the ledger for the ITR filing.
Advance tax reconciliation for Indian companies involves matching the estimated tax liability calculated each quarter to the Challan 280 payments made before each instalment deadline, and then verifying that each payment appears as a credit in Form 26AS before the annual return is filed. A Challan 280 payment that does not reflect in Form 26AS is not a posted tax credit — and a missed instalment that goes undetected until return filing produces Section 234B and 234C interest that could have been avoided.
This guide is for CFOs, tax controllers, and finance managers responsible for corporate advance tax compliance.
What Advance Tax Reconciliation Involves
Advance tax reconciliation connects four data points:
- Estimated tax liability — the tax calculated on projected income for the assessment year, revised at each instalment date as actual results become clearer.
- Challan 280 payment — the amount paid before each instalment deadline, with the assessment year and tax type correctly specified.
- CIN (Challan Identification Number) — the three-part identifier (BSR code + deposit date + challan serial number) that links the payment to the company’s PAN.
- Form 26AS credit — the advance tax credit appearing in Part F of Form 26AS, keyed by CIN and payment date.
Reconciliation confirms that all four agree. When they do not, the cause is typically a CIN mismatch (payment not yet reflected in Form 26AS), an instalment calculation error, or a challan filed under a wrong field.
Advance Tax Instalment Schedule
| Instalment | Due Date | Cumulative % of Tax Liability | Challan Type | Interest Risk if Missed |
|---|---|---|---|---|
| First | 15 June | 15% | Challan 280 (Code 100) | Section 234C — 1% per month for 3 months on shortfall |
| Second | 15 September | 45% | Challan 280 (Code 100) | Section 234C — 1% per month for 3 months on shortfall |
| Third | 15 December | 75% | Challan 280 (Code 100) | Section 234C — 1% per month for 1 month on shortfall |
| Fourth | 15 March | 100% | Challan 280 (Code 100) | Section 234B — 1% per month from April 1 if total advance tax below 90% of assessed tax |
How Advance Tax Reconciliation Works
Step 1 — Calculate the Instalment Amount
Before each instalment deadline, the tax team calculates the estimated full-year tax liability based on year-to-date actuals and projected income for the remainder of the year. The cumulative advance tax due is the prescribed percentage of this estimate. The current instalment payment is the shortfall between cumulative tax due and cumulative advance tax already paid.
Step 2 — Pay Challan 280 and Record the CIN
Pay the instalment via Challan 280 on the NSDL/Income Tax portal or through a bank branch. Record the CIN from the payment confirmation: BSR code (7 digits) + deposit date (DDMMYYYY) + challan serial number (5 digits). This CIN is the primary match key for Form 26AS verification. The bank narration for online payments follows: OLTAS ADVANCE TAX AY 2026-27 CHALLAN 280.
Step 3 — Match CIN to Form 26AS
Check Form 26AS Part F within 3–7 working days of payment. The CIN should appear with the payment amount, assessment year, and payment date. If it does not appear within 7 working days, initiate a challan status inquiry on the OLTAS portal using the CIN, or contact the bank that processed the payment.
Step 4 — Reconcile the Advance Tax Ledger
The advance tax ledger in the books should record each instalment payment by date and amount. The cumulative ledger balance at each quarter end should match the cumulative payments reflected in Form 26AS. Any difference — even a timing difference — must be documented with the CIN and the expected Form 26AS update date.
Common Advance Tax Reconciliation Mismatches
Wrong assessment year on Challan 280. Payment for FY 2025-26 (AY 2026-27) filed as AY 2025-26 credits to the wrong year. Form 26AS for AY 2026-27 shows no credit; Form 26AS for AY 2025-26 shows a surplus. Correction requires a challan correction application through the paying bank.
CIN not appearing in Form 26AS after 7 working days. This is the most common reconciliation query. The resolution path is: (1) confirm the payment cleared the bank account; (2) check OLTAS portal challan status using BSR code + date + serial; (3) if OLTAS shows the challan but Form 26AS does not, the data upload is pending — it typically clears within 48 hours of the OLTAS status appearing; (4) if OLTAS also shows no record, contact the bank branch.
Instalment percentage miscalculated. The cumulative percentages (15%, 45%, 75%, 100%) apply to the estimated full-year liability, not to the remaining liability. A common error is calculating each instalment as a percentage of the remaining tax — this underestimates the September instalment and triggers Section 234C interest.
The Income Tax India — Official Portal provides Challan 280 payment instructions, OLTAS challan status verification, and Form 26AS access for all registered taxpayers.
For companies reconciling both advance tax (Challan 280, CIN-based) and TDS payments (Challan 281, BSR-code-based), TDS reconciliation software that handles CIN-level matching for advance tax alongside challan-level matching for TDS deposits reduces the reconciliation surface to a single exception register. The bank reconciliation statement India covers the bank statement matching that underlies CIN verification. Where a Challan 280 payment does not appear in Form 26AS, the diagnostic process mirrors the TDS challan mismatch resolution approach. For companies where advance tax reconciliation is part of a broader reconciliation software India deployment, the advance tax ledger should integrate with the TDS receivable ledger — see TDS receivable ledger reconciliation for how the two interact at year-end.