Short answer: In Tally, the same supplier bill usually gets paid twice because the supplier invoice number was typed differently, the supplier has two ledgers, or payments were made On Account instead of against the bill (Agst Ref). Export your purchase and payment registers, normalise invoice numbers, and match by GSTIN and amount to find them.
Five ways the same bill gets paid twice
- Invoice number typed differently. 102/26/1620 in one voucher and 102-26-1620 in another. Both are accepted, both are paid.
- Two ledgers for one supplier. "Shree Steel" and "Shree Steels Pvt Ltd" with the same GSTIN. Each ledger shows a clean balance.
- Payments On Account. When payments are entered as On Account instead of Agst Ref (against the bill), Tally can't show which bills are settled, so a settled bill still looks open.
- Advance plus bill. An advance is paid, then the full bill is paid later without adjusting the advance.
- Bill entered twice. Once as a purchase voucher by accounts, once as a journal by the plant or site office.
How to find them in your data
- Export the Purchase Register (detailed) and the Payment Register for the last 12 months to Excel.
- Normalise supplier invoice numbers: remove spaces, slashes, dashes and leading zeros.
- Match on supplier GSTIN + normalised invoice number. Every match is almost certainly a duplicate.
- Look wider: same GSTIN, amount within 1%, dates within 30 days. Check each by hand.
- Check ledgers: list supplier ledgers by GSTIN. Two ledgers with one GSTIN should be merged.
- Review On Account: any supplier with large On Account payments and open bills needs bill-wise adjustment.
How to recover the money
Share both bills and both payments with the supplier and ask for a credit note, or raise a debit note and adjust it against their next bill. With the evidence attached, most suppliers agree quickly.
How to stop it in Tally
- Turn on bill-wise details for every supplier, and always pay Agst Ref, never On Account.
- Keep one ledger per GSTIN.
- Agree one standard format for typing supplier invoice numbers.
- Before each payment run, check the bill against the PO and goods receipt.
In our sample audit, duplicate supplier payments came to 0.6% of turnover. On a ₹25 Cr business, that would be about ₹15 lakh.
Questions
Does Tally block duplicate supplier invoice numbers?
Tally records what is entered. A number typed in a different format, or entered against a different ledger, is treated as a new bill, so you need a separate check.
How far back should we check for duplicates?
At least the last 12 months. Older duplicates can often still be recovered from suppliers you continue to buy from.
Can Prozone check our Tally data without login access?
Yes. We only need exported registers. We never ask for your Tally login, and you can mask supplier names before sharing.