How to Calculate Interest in Tally Prime (2026)

If you charge customers interest on overdue payments, or need to track interest payable on loans and delayed supplier payments, manually calculating this for every overdue bill gets tedious fast. Tally Prime’s Interest Calculation feature applies an interest rate automatically based on bill-wise outstanding details, so the number is ready whenever you need it instead of being recalculated by hand.

This guide covers setting up interest calculation and applying it to overdue bills.

What You Need Before You Start

• Tally Prime installed, with Bill-wise Details already enabled — see our guide on how to manage outstanding receivables and payables in Tally Prime, since interest calculation depends on accurate bill references and due dates
• A clear interest rate and method (simple or compound) you actually intend to apply, ideally matching what’s stated in your terms of sale or loan agreement

Step 1: Enable Interest Calculation

1. Gateway of Tally, then F11 (Features), then F1 (Accounting Features)
2. Confirm Maintain Bill-wise Details is set to Yes (a prerequisite for bill-wise interest calculation)
3. Set Activate Interest Calculation to Yes
4. If you want more control over rate, style (simple/compound), and calculation basis at the ledger level rather than a blanket setting, also enable the advanced parameters option shown alongside this setting
5. Press Ctrl+A to save

Step 2: Configure Interest Parameters on the Party Ledger

1. Open the relevant customer or supplier ledger
2. Confirm Activate Interest Calculation is set to Yes for this specific ledger
3. Choose the Rate (annual percentage)
4. Choose the Interest Style — Simple Interest or Compound Interest, and the compounding frequency if compound is selected
5. Choose the Interest Balances Beginning From date and whether calculation should apply on the bill’s due date, voucher date, or another basis depending on your agreed terms
6. Save the ledger

Step 3: Confirm Due Dates Are Set Correctly on Bills

Interest calculation depends heavily on accurate due dates from your bill-wise tracking:

1. When recording sales or purchase invoices, make sure the Due Date or Credit Days field is filled in correctly for each bill
2. If a due date is missing or wrong, the interest calculation for that specific bill will be inaccurate, even if your overall ledger settings are correct

Step 4: Calculate and View Interest

1. Gateway of Tally, then Display More Reports, then Statement of Accounts, then Interest Calculations
2. Select the relevant party or ledger
3. Review the calculated interest amount, shown against each overdue bill individually
4. Adjust the “calculate as on” date if you want to see the interest as of a specific date, such as today, or a future date for planning purposes

Step 5: Record the Interest as a Transaction (If You’re Charging or Paying It)

Calculating interest in the report doesn’t automatically post it to your books — if you actually want to invoice or formally record the interest:

1. Use a Debit Note (if you’re charging interest to a customer) or a Credit Note/Journal (if you’re recording interest payable to a supplier), referencing the relevant outstanding bill — see our guide on how to record debit note and credit note in Tally Prime
2. Many Tally Prime releases let you pull the calculated interest amount directly from the Interest Calculation report into a new voucher, rather than manually re-typing the figure
3. Save the voucher, which then reflects as an actual addition to what’s owed

Common Mistakes to Avoid

• Enabling interest calculation at the company level but forgetting to also enable and configure it on the specific party ledgers you care about
• Leaving due dates blank or incorrect on bills, which silently breaks the accuracy of every interest calculation tied to that bill
• Applying interest rates that don’t match what’s actually stated in your customer agreements or loan terms, creating a dispute risk if challenged
• Treating the interest calculation report as if it were already a recorded transaction, when it’s a calculation tool until you actually post it via a voucher
• Forgetting to update the calculation basis (simple vs compound, and compounding frequency) when terms change for a specific party

FAQs

Does Tally Prime apply interest automatically without me doing anything? No. Tally Prime calculates the interest figure based on your configured rate, style, and outstanding bill data, but you still need to view the report and decide when and how to actually post that as a transaction.

Can I use different interest rates for different customers? Yes, interest parameters are configured per ledger, so you can set different rates, styles, and calculation bases for different customers or suppliers as needed.

What’s the difference between simple and compound interest in this context? Simple interest calculates a flat percentage on the outstanding principal for the overdue period. Compound interest recalculates on a principal that includes previously accrued interest, compounding at the frequency you specify, resulting in a higher amount over longer overdue periods.

Can interest calculation work without bill-wise details enabled? Bill-wise interest calculation, which ties interest to specific overdue bills and their due dates, requires bill-wise details to be enabled. Without it, the calculation has nothing accurate to base the overdue period on.

Is charging interest on overdue customer payments legally enforceable? This depends on your terms of sale or agreement with the customer, and applicable law. Make sure any interest you charge is consistent with what was actually agreed or disclosed, and consult a legal advisor if you’re unsure about enforceability in a specific case.