Stops an exact repeat
When you save a new Purchase or Journal voucher, it compares the supplier, the invoice number and the amount with what is already booked.
Free Chartford add-on for TallyPrime
Restrict Duplicate Invoice
Stop one bill being booked twice.
TallyPrime will save a second voucher with the same supplier invoice. That can mean paying the bill twice and claiming the GST credit twice. This add-on stops the entry when the supplier, the invoice number and the amount all match. It also lists the repeats already in your books.
or scroll down to see it work ↓
Supplier Invoice No.NT/2411
Party A/c nameNorthwind Traders Pvt Ltd
Amount1,18,000.00
Duplicate invoice.Same supplier, same Supplier Invoice No. and same amount are already booked in this period.
Built and tested on TallyPrime 7.1 · installs in 2 minutes · posts nothing · your data never leaves your computer
Why it matters
A bill entered twice looks like two real bills.
It happens easily. Two people book the same invoice. A bill comes by email and again by courier. Someone books it again at year end because they could not find the first entry. Tally saves the second voucher without a word.
After that, your purchases and your input tax credit are both too high, and the supplier’s ledger shows money you do not owe. If nobody notices, the bill gets paid again. The usual time to find out is the GST reconciliation or the audit, long after the money has gone.
Made for CAs who check clients’ books and for company accounts teams who enter purchases every day.
The rule
It stops a real repeat, and lets an honest split go through.
The same invoice number is not always a mistake. A courier’s invoice is often entered in two parts: duty by journal and handling charges by purchase. So the amount decides.
| What you are entering | What happens |
|---|---|
| Same supplier, same invoice number, same amount | Stopped on save |
| Same supplier, same invoice number, different amount | A warning. You can continue |
| Different supplier, same invoice number | Allowed |
| A journal that debits the supplier and quotes the invoice number, such as a re-charge or a reversal | Allowed |
| The earlier voucher is cancelled or optional | Allowed |
“INV 001” and “inv001” count as the same number: spaces and capitals are ignored. “INV/001” is a different number.
See the repeats already in your books
The finder opens on the whole year, in two lists.
Go to Gateway of Tally → Chartford → Duplicate Supplier Invoice Finder. List A is what to check first. List B is usually fine, and it is there so you can be sure.
Duplicate Supplier Invoice FinderDEMO COMPANY PVT LTD · 1-Apr-25 to 31-Mar-26
A. Same amount: 2 groups, 4 vouchersB. Different amounts: 2 groups, 5 vouchers
A. SAME NUMBER AND SAME AMOUNT: likely booked twice
| Supplier | Supplier Invoice No. | Copies | Amount | Last vch no. | Last vch date |
|---|---|---|---|---|---|
| Meridian Supplies Co | 0318 | 2 | 23,600.00 | 287 | 3-Sep-25 |
| Northwind Traders Pvt Ltd | NT/2411 | 2 | 1,18,000.00 | 412 | 14-Nov-25 |
B. SAME NUMBER, DIFFERENT AMOUNTS: usually one invoice split across vouchers
| Supplier | Supplier Invoice No. | Copies | Lowest | Highest | Last vch no. | Last vch date |
|---|---|---|---|---|---|---|
| Bexley & Co LLP | BX/4471 | 3 | 1,180.00 | 1,86,200.00 | 356 | 8-Oct-25 |
| Crestline Systems | CS-77 | 2 | 1,200.00 | 14,160.00 | 198 | 21-Jul-25 |
Demo company. No real supplier or amount is shown. Press Enter on a row to open that supplier’s ledger vouchers, find the invoice number and correct it. The list shows the last voucher of each group, not every voucher in it.
What it does
Checks at the moment of entry, then gets out of the way.
stop
warn
Warns early
On a Purchase, the moment you choose a supplier whose invoice number is already booked, it tells you. A Journal gets the same warning on save.
Cr
Only real bookings count
A voucher counts only if it credits the supplier. A journal that debits the supplier is an adjustment, not a second bill.
list
Finds the old repeats
The finder lists every repeat already in the period, so you can clean up the books you have, and not only the entries to come.
edit
Careful with edits
Change a number or a party on an old voucher so that it matches another bill of the same amount, and it stops you. Change only the narration on an old repeat, and it saves.
FY
Year by year
It compares inside the period you have open. Many suppliers start again from 1 every April, so the same number last year is not a repeat.
safe
Posts nothing
It adds no field, stores no data and posts no voucher. Remove the file and your Tally screens are exactly as before.
2min
Two-minute install
Load one file into TallyPrime. No licence key and no expiry. It sits under Gateway of Tally → Chartford.
How it works
From email to working check in four steps.
- Tell us where to send it. We email you the file and the user manual, free.
- Try it on a copy first. Press F1, then TDLs & Add-Ons, then F4. Add the file and press Ctrl+A. Use a copy of your company, or take a fresh backup.
- Enter a repeat on the copy. Book a bill you know is already there, with the same amount. You will see the warning, then the stop on save.
- Open the finder. Gateway of Tally → Chartford → Duplicate Supplier Invoice Finder. Work through list A, and press Enter on a row to reach the vouchers.
Get it free
No payment, no card, nothing to expire.
Tell us where to send it and we email you the file with install steps. It is free and it stays free. It is yours to keep and to share.
We use your email to send the file and the manual, and to tell you if a new version ships. Reply “stop” at any time and we will not write again.
Straight answers
Common questions
A supplier really did use the same number and amount twice. What do I do?
Enter the number with a small difference, such as INV001-A, and say why in the narration. It stays visible and it does not block you.
Which vouchers does it check?
Purchase and Journal vouchers, including voucher types you created under them. It does not check Debit Notes, Credit Notes, Payments or Sales. A Journal is checked only if it has a reference number and credits a supplier under Sundry Creditors.
What can it miss?
- Other periods. It compares inside the period you have open. In a month-wise view it compares only that month, so work in the whole-year view.
- A different amount. The amount must match to the paisa to be stopped. A repeat booked with a corrected amount gets the warning only.
- A typed-differently number. “INV/001” and “INV-001” are different numbers to it.
- An edited amount. If you edit an old voucher and change only its amount so that it matches another bill, nothing stops it.
Will it slow down my Tally?
It reads the period’s Purchase and Journal vouchers when the cursor leaves the number or the party field, and again on save. On a very large company you may notice a pause. We have not timed it on very large books, so try it on a copy and tell us how it goes.
Which TallyPrime versions does it work on?
It is built and tested on TallyPrime 7.1. The parts of Tally it relies on are the same in 5.1 and 6.x, but we have not run it on those releases. Tell us your release and how it goes.
Does my data leave my computer?
No. It runs inside your own TallyPrime on your own company data. Nothing is uploaded to us or anyone else.
How do I switch it off?
Remove the file from F1, TDLs & Add-Ons. It stores nothing in your company, so your books and screens are exactly as before.
Is it really free?
Yes. No licence fee, no trial clock and no activation key. We ask for your email so that we can send you the file.
