When you earn income in India, the government expects you to pay tax during the year itself, not just at the end. This is called advance tax.
But many people either forget to pay it or pay less than required. In such cases, the Income Tax Act charges interest for delay or short payment. This is covered under Section 424 – Interest for Default in Payment of Advance Tax.
Let’s understand this in a simple, practical way so you know exactly what happens and how it affects you.
What is the Basic Idea Behind This Rule?
The government wants tax to be paid on time throughout the year.
If you delay or underpay, it means the government did not receive its money when it should have. So, you have to pay interest for that delay.
Think of it like this: You used money that should have gone to the government, so you pay a small cost for that.
When Does Section 424 Interest Apply?
This interest applies if you were required to pay advance tax, but:
- You did not pay any advance tax at all even though you were liable, you skipped it completely.
- You paid less than 90% of your total tax. You paid something, but it was not enough.
If your advance tax is 90% or more, then generally this interest does not apply.
How Much Interest Do You Have to Pay?
As per section 424, the interest rate is: 1% per month (simple interest)
Even if the delay is just a few days, it is counted as a full month.
Interest is calculated from 1st April after the financial year until the date of processing of your return (intimation) or date of final assessment.
So basically, the delay period starts after the year ends and continues until your tax is properly calculated and paid.
On What Amount is Interest Charged?
This depends on your situation:
- If you paid no advance tax: interest is on the full tax amount
- If you paid some advance tax: interest is on the shortfall amount
In simple terms, interest is charged only on the unpaid portion.
What is “Assessed Tax” (Very Important Concept)
Assessed tax means your final tax liability, but after reducing certain amounts already paid or adjusted. It is calculated after subtracting things like:
- TDS (tax already deducted, like salary TDS)
- Tax relief (if allowed)
- Foreign tax credits (if you paid tax abroad)
So, interest under section 424 of the new income tax act 2025, is not charged on the full income—only on the remaining tax you were supposed to pay.
Example
Let’s say:
- Your total tax liability = ₹1,00,000
- TDS already deducted = ₹20,000
- So, remaining tax = ₹80,000
Now:
- You paid advance tax = ₹50,000
- Shortfall = ₹30,000
- Since you paid less than 90%, interest will apply to ₹30,000.
If the delay is 5 months:
- Interest = 1% × 5 months = 5%
- Interest amount = ₹30,000 × 5% = ₹1,500
What If You Pay Tax Late (After the Year Ends)?
If you pay some tax later (before assessment), then Interest is calculated till the date you paid that amount.
After that, interest is calculated only on the remaining unpaid balance.
So, paying earlier can reduce your interest burden.
What Happens If Tax is Recalculated Later?
Sometimes, your income is reassessed later, and your tax liability increases.
In that case:
- Interest will be recalculated on the extra tax amount
- It will be charged again from 1st April after that year
So, even after filing your return, changes can increase your interest.
What If There is a Correction or Appeal?
If later:
- your tax liability increases, you pay more interest
- your tax liability reduces, extra interest you paid will be refunded
So, interest always adjusts based on the final correct tax amount.
Many beginners think:
“I’ll just pay tax when filing the income tax return (ITR).”
This is where mistakes happen.
Here’s what you should understand:
- Advance tax is not optional if you meet the conditions.
- Paying late leads to automatic interest (no escape).
- Even small delays count as full months.
- Interest keeps adding until your tax is fully settled.
This interest is not a penalty, but it still increases your total tax outflow.
Conclusion
Interest on default in advance tax is simply a charge for not paying tax on time during the year. If you either skip advance tax or pay less than required, you will have to pay 1% per month on the shortfall.
The best way to avoid this is to estimate your income properly and pay advance tax in time. Once you understand this system, managing your taxes becomes much easier and stress-free.
