Tax year: the new terminology explained

The tax year is the 12 months from 1 April in which you earned the income, written as, for example, 2025-26 for 1 April 2025 to 31 March 2026. You file your return for a tax year after it ends, from 1 April onwards. Under the Income-tax Act, 2025, the tax year is the only year label you need.

The Income Tax Department describes the tax year under the 2025 Act as a twelve-month period within an April–March year. It replaces the "previous year" of the 1961 Act, and the 2025 Act does not use the term "assessment year". A tax year can be shorter than twelve months for a business set up part-way through the year.

Which year are you filing for?

So in the 2026 filing season you file for the tax year 2025-26, which is still under the 1961 Act. The first return under the Income-tax Act, 2025 is for the tax year 2026-27, and it is filed from April 2027.

Matching older labels to the tax year

Older forms, circulars and some portal screens use a second year label, called the assessment year, which runs one year ahead of the income year.

To match such a label to a tax year, subtract one from both halves, so a label of 2026-27 on an older screen means the tax year 2025-26.

TaxCare shows only the tax year in its screens and documents, and converts the portal's label for you.

Dates that follow from the tax year

Here are dates for the tax year 2025-26, which is the one being filed in 2026:

For a belated return, the deadline is 31 December after the tax year ends. A revised return can be filed until 31 March after the tax year ends, from the tax year 2025-26. An updated return (ITR-U) can be filed from 1 January until 48 months after the end of the year that follows the tax year, with extra tax of 25%, 50%, 60% or 70% depending on how late it is.

These windows are for the tax year 2025-26 under the 1961 Act. How they are counted for the tax year 2026-27 under the Income-tax Act, 2025 is not covered here; see the due dates guide below for what is confirmed.

See ITR due dates for the tax year 2026-27 for the dates ahead.

What changes in the Income-tax Act, 2025

The new Act renumbers sections. Examples from the department's own crosswalk:

Our rule sets for the tax year 2026-27 are provisional: they carry forward the 2025-26 figures and have not been signed off against the new Act or the Finance Act 2026. See Form 26AS vs Form 168.

Common mix-ups

• Calling the 2025-26 return the "2026-27 return". The return filed in 2026 is for the tax year 2025-26.
• Using Form 26AS for 2026-27. From the tax year 2026-27 it is Form 168.
• Counting years from the filing date. Count from 1 April in which the income was earned.
• Mixing labels in a form. Use the tax year when you speak to TaxCare, and subtract one when reading an older label.

How TaxCare helps

TaxCare labels everything by tax year, picks Form 26AS or Form 168 from the year, shows the due dates for the year, and converts the portal's year label automatically. If you are unsure which year a notice or an old document refers to, a Tax Expert can help. See Tax Experts and how to file income tax return online.

This guide gives general information and is not professional tax advice.