143(1) Demand After Paying Self-Assessment Tax: How to Fix It

A 143(1) demand after you have already paid self-assessment tax usually means the Income Tax Department could not match your payment to your return, not that you owe the money twice. The most common causes are challan details missing from Schedule IT, details entered incorrectly, or tax paid under the wrong assessment year or payment type. In most cases the fix is to tell the Department about the payment or correct the record, not to pay again.

This guide explains what a 143(1) demand is, why it appears even after you paid, how to check what went wrong, and the official ways to respond: through the outstanding demand facility, a challan correction, or a rectification request under section 154.

What a 143(1) demand actually is

When you file your income tax return, the Department processes it and sends an intimation under section 143(1). The intimation compares the tax you computed and paid with the figures the Department holds. It can show that nothing further is due, that a refund is payable, or that there is a demand.

A 143(1) demand is the Department’s calculation of tax it believes is still unpaid after processing. It is an intimation, not a scrutiny assessment. Many 143(1) demands arise from simple mismatches between your return and the payment records, which is why they can often be resolved without paying any extra tax.

Which law applies to returns filed in 2026

The Income-tax Act, 2025 came into force on 1 April 2026, which has led many taxpayers to ask whether section 143(1) still applies. According to the Central Board of Direct Taxes’ transition FAQs, the return for income earned during financial year 2025-26 is filed for assessment year 2026-27 under the Income-tax Act, 1961. That holds even though the return is filed after 1 April 2026. So a 143(1) intimation for that year is dealt with under the 1961 Act.

Why a 143(1) demand appears after you paid self-assessment tax

If you paid the balance tax before filing and still received a 143(1) demand, the payment was almost certainly not matched to your return. These are the usual reasons.

The challan was not entered in Schedule IT

Self-assessment tax and advance tax are reported in Schedule IT of the return, which records the details of each tax payment. The schedule captures the BSR code of the bank branch, the date of deposit, the challan serial number and the amount paid. If you paid the tax but left this schedule blank, the processed return does not count the payment, and a 143(1) demand follows.

The challan details were entered incorrectly

Even when Schedule IT is filled in, a single wrong digit in the BSR code, the challan serial number or the date can stop the payment from matching. The Department’s records hold the payment, but they cannot link it to the entry in your return.

The tax was paid under the wrong assessment year

Tax paid against the wrong assessment year is credited to that year, not to the return you filed. The payment exists, but it sits in the wrong place, so the return being processed still looks underpaid.

The wrong type of payment was selected

Each tax payment carries a minor head that describes its type. The Department’s challan correction manual lists the three main ones: 100 for advance tax, 300 for self-assessment tax, and 400 for demand payment as regular assessment tax. Paying under an unintended minor head can cause the payment to be treated differently from what you intended.

A TDS or TCS credit did not match

Sometimes the problem is not your self-assessment tax at all. A demand can also arise when tax deducted or collected at source that you claimed in the return does not match the Department’s records. The rectification facility has a specific option for this kind of tax credit mismatch.

What to have ready before you respond

Gathering the right documents first makes the response quicker and reduces the chance of a second mismatch. Keep these to hand:

• The 143(1) intimation. It shows the Department’s computation and the demand amount.
• The tax payment challan. Note the BSR code, challan serial number, date of deposit, amount, assessment year and minor head.
• A copy of the challan to upload. The portal asks you to attach it when you confirm a payment.
• The return you filed. Check what you entered in Schedule IT.
• Form 26AS or your Annual Information Statement. This shows how the payment is recorded against your PAN.

Check what went wrong

Before responding, work out which of these causes applies. Guessing leads to the wrong fix. A few checks usually settle it.

• Read the intimation carefully. Compare the tax paid figure in the Department’s computation with the figure in your return. The gap usually equals the payment that was not matched.
• Look at your challan. Note the BSR code, the challan serial number, the date of deposit, the amount, the assessment year and the minor head.
• Check Form 26AS or your Annual Information Statement. See whether the payment appears there and against which assessment year.
• Open the return you filed. Check whether the payment was entered in Schedule IT, and whether each detail matches the challan exactly.

If the challan shows the correct assessment year and minor head, and it appears in your tax records, the issue is almost always in Schedule IT. If the assessment year or minor head on the challan is wrong, the fix lies with the challan itself. Our guide to Form 26AS vs AIS explains where to find these records.

Option 1: Respond to the outstanding demand

The Department’s e-Filing portal lets you respond to a 143(1) demand directly. According to its user manual, you log in and go to Pending Actions, then Response to Outstanding Demand, where your demands are listed. The manual sets out three scenarios.

• The demand is correct and you have not paid it. In this case you pay the amount due.
• The demand is correct and you have already paid it. You confirm the payment by entering the challan details and uploading a copy of the challan.
• You disagree with the demand, fully or in part. You select the reasons for disagreeing and provide the supporting details for each reason.

When you tell the Department you have already paid, the portal asks for the type of payment, which is the minor head, along with the challan amount, the BSR code, the serial number and the date of payment. You then attach a copy of the challan. This is the most direct route when the tax was paid correctly but simply not matched to your return.

Option 2: Correct the challan itself

If the mistake is on the challan, such as the wrong assessment year or the wrong minor head, the Department offers a challan correction facility on the e-Filing portal. The time limits are short, so check them first.

• Changing the assessment year: the request must be made within 7 days of the challan deposit date.
• Changing the major head or the minor head: the request must be made within 30 days of the challan deposit date.

The facility has conditions. It covers minor heads 100, 300 and 400, and challans for assessment year 2020-21 onwards. The challan must not already have been consumed during processing, and the request must not be pending with another authority. For other minor heads, or once the portal window has passed, the manual directs taxpayers to the jurisdictional Assessing Officer.

That condition about consumption matters for a 143(1) demand. By the time you receive the intimation, the return has already been processed. A challan correction is most useful when you spot a wrong assessment year or minor head soon after paying, before processing.

Option 3: File a rectification request under section 154

A rectification under section 154 corrects a mistake apparent from the record. It is the right route when the processed return itself needs to be corrected, for example because the tax credit was not given. According to the Department, you go to the Services menu, click Rectification, select New Request and choose the assessment year.

The Department lists three request types:

• Reprocess the Return: asks the Department to process the return again.
• Return Data Correction (Offline): used to correct data in the return.
• Tax Credit Mismatch Correction: used where the tax credit claimed did not match the Department’s records.

A rectification is not a new return. It is a request to fix an error in a return that has already been processed. You can track the status of the request on the portal.

Which option should you use?

The right route depends on where the error sits. This summary maps each cause to its usual fix.

If the case is complex, if the amount is large, or if the portal windows have passed, a chartered accountant can review the intimation and your records before you respond.

Advance tax and self-assessment tax: the difference

Both types of payment are reported in Schedule IT, but they are paid at different times, which is why they carry different minor heads.

Advance tax is paid during the year in which the income is earned, in instalments, under minor head 100. The CBDT transition FAQs set out the instalment schedule: not less than 15% by 15 June, 45% by 15 September, 75% by 15 December, and 100% by 15 March.

Self-assessment tax is the balance you compute and pay yourself before submitting your return, under minor head 300. It covers whatever remains after advance tax and tax deducted or collected at source.

Mixing the two up on a challan is one of the ways a payment can fail to match your return, so it is worth checking the minor head on every challan before you file.

Common mistakes to avoid with a 143(1) demand

• Paying the demand again without checking. If you already paid, paying a second time creates an excess that you then have to recover. Confirm the payment first.
• Ignoring the intimation. An unresolved demand can remain outstanding against your PAN. Respond through the portal once you know the cause.
• Using the wrong minor head when paying a genuine demand. A demand is paid as regular assessment tax, which is minor head 400, not as self-assessment tax.
• Missing the challan correction window. The assessment year can be changed online only within 7 days of deposit, and the major or minor head within 30 days.
• Filing a revised return when a rectification is enough. If the only problem is an unmatched payment, the demand response or rectification is usually the simpler route.

For related reading, see our guides to why an income tax refund may not arrive and how income tax scrutiny notices work.

Frequently asked questions