Salary Arrears Calculator: Formula, PF and TDS Treatment

Salary revisions are not always implemented from the same month in which they become effective. For HR and payroll teams, the calculation is straightforward in principle, but it becomes easy to get wrong when the arrear period covers several months or additional payroll adjustments are involved. Our Salary Arrears Calculator helps you estimate the arrears by comparing the salary actually paid with the salary that should have been paid during the selected arrear period.

The Formula, and Why One Line Is Not Enough

The starting point is simple:

Arrears = (New Salary – Old Salary) × Number of Months Due

But if you apply this to gross salary alone, you lose the ability to recalculate PF, because PF depends on Basic + DA, not gross. So work it component by component.

Take an employee whose increment was approved in September 2026, effective 1 April 2026. That makes five months of arrears (April to August).

Now the statutory side. If PF is calculated on actual Basic (not capped at a wage ceiling), the extra PF is 12% of ₹6,000 = ₹720 from the employee, and a matching ₹720 from the employer. ESI does not apply here because gross salary is above ₹21,000. Professional Tax depends on your state and on whether your state counts arrears in that month’s gross for slab purposes – worth checking rather than assuming. Net arrears before tax: ₹12,000 − ₹720 = ₹11,280.

Two practical notes on the “months due”. For a mid-month effective date, use the same day-count basis your payroll already uses (many companies use 26), so the arrears follow the same logic as the salary itself. And if the employee had loss-of-pay days in any of those months, recalculate those months separately instead of multiplying blindly.

PF and ESI on Arrears

For PF, the general position in the sources I reviewed is that arrears attract contribution in the month they are actually paid, on the Basic + DA portion, for both employee and employer shares. ESI follows the same idea if the employee is covered, applied at 0.75% (employee) and 3.25% (employer) on the relevant wages.

There is one area where I would not rely on a general rule. The EPF wage ceiling moved from ₹15,000 to ₹25,000 from 17 September 2026. If you are paying arrears after that date for months that fall before it, or for an employee whose contribution was capped at the old ceiling, I have not found clear guidance on which ceiling applies to the arrears. Do not assume. Ask your PF consultant, and keep their answer on file.

TDS on Arrears

Arrears are taxable in the year they are received, not the year they relate to. Your payroll should therefore add them to the employee’s estimated income for the year and recompute TDS from that month onward. The visible effect is a sharp TDS deduction in the month arrears are paid, which surprises employees who were only expecting good news.

My advice is to tell the employee before the payroll runs: the arrears amount, the statutory deductions on it, and roughly how much TDS will be withheld. That one conversation prevents most of the “why is my net pay lower than the increment suggests” queries.

Tax Relief When Arrears Belong to Earlier Years: 89(1) and Form 10E, or 157 and Form 39

Here is the point most quick guides skip: relief is only relevant when arrears relate to earlier years and bunching them into one year pushes the employee into a higher slab. In the example above, all five months fall in the same year the arrears are paid (April to August 2026, paid in September 2026). Nothing is bunched across years, so there is no relief to claim.

Relief matters when, say, a pay revision effective January 2026 is paid in September 2026, or when a multi-year settlement lands in one payroll. In that case, the older provision is Section 89(1), claimed by filing Form 10E on the income tax portal before filing the return; skipping it can get the relief disallowed. For FY 2025-26 income (assessment year 2026-27), which is still governed by the 1961 Act, that is the route that applies. Under the Income-tax Act 2025, from Tax Year 2026-27, the corresponding provision is Section 157 and the form is Form 39.

You can see this reflected in the new formats themselves. Part C of Form 130 carries a line for relief under Section 157, and Annexure II of Form 138 has columns for the Form 39 acknowledgment number and for income (arrears or advance) on which Section 157 relief is claimed. So this is no longer just an employee-side ITR matter; it shows up in what the employer files.

One situation deserves a caution: arrears paid in Tax Year 2026-27 that relate to months in FY 2025-26 sit across the old and new Act. That is exactly the kind of case where I would ask your CA to confirm which provision and form apply, rather than guess. Also remember that the relief calculation uses the slabs and regime applicable to each relevant year, and that Form 10E or Form 39 is filed by the employee on the portal, not with the employer. If you want relief considered while deducting TDS, the employee needs to give the particulars early.

Payslip and Records

Show arrears as a separate line on the payslip, labelled with the period they cover (for example, “Arrears – Apr to Aug 2026”), rather than merging them into basic or a bonus head. Keep the revision approval, the component-wise worksheet, and the differential PF and TDS workings together.

The reason to break arrears up by month and financial year is practical: if the employee needs to claim relief, the year-wise split is the first thing their CA will ask for. If your payroll cannot produce it, someone will end up rebuilding it from old payslips.

Mistakes I See Most Often

Applying the whole difference to Basic (or the whole difference to a single allowance) and leaving HRA and other linked components untouched. Calculating PF on gross arrears instead of Basic + DA. Ignoring loss-of-pay days in the affected months. Adding arrears to the current month without checking how the state counts them for Professional Tax. Not splitting arrears by financial year. And not warning the employee that TDS will spike.

What Should HR Check Before Calculating Arrears?

Before calculating salary arrears, HR should verify:

• Effective date
• Salary revision
• Payroll already processed
• Arrear period
• Additional adjustments
• Salary components

What If the Salary Changed More Than Once?

This is where a basic salary-arrears calculator has a limitation.

Suppose an employee’s salary was:

• ₹50,000 from April to June
• ₹55,000 from July to August
• ₹60,000 from September onward

A single old salary and revised salary cannot accurately represent the entire period.

The payroll calculation would need to be split into separate periods.

For example:

April–June: first salary difference
July–August: second salary difference
September onward: third salary difference

For such cases, HR should use the employee’s salary revision history and calculate each effective period separately.

How Runtime HRMS Helps

Everything above depends on one thing: knowing exactly which salary applied in which month. Runtime HRMS keeps salary revisions with effective dates, so the old and new structures for each month are on record instead of living in someone’s spreadsheet. That is the foundation arrears are built on.

If you are still calculating arrears manually and rebuilding the year-wise split every time, see how Runtime HRMS handles payroll and statutory calculations.

Check Our Other Calculators and Resources

Disclaimer

This guide is for general information and reflects the position as understood at the time of publication. Tax and PF treatment can vary with individual facts, the applicable Act and regime, and further government clarification – particularly for arrears that cross financial years or the EPF wage ceiling change.

For official references: Income Tax Department e-filing portal | EPFO