In this guide 7 sections
Your sales register and Tally disagree because documents are created or posted differently, rarely because of the tax rate. Rounding rules, cancelled invoices, unlinked credit notes and invoices raised elsewhere are the usual causes. Compare one month document by document to find yours. GullySystem builds a daily reconciliation so gaps surface the next morning.
Rounding applied in two places
Billing software may round each line, then round the total again. Tally may round only at the invoice level. Small differences add up across hundreds of bills, and by month-end the gap looks like a missing invoice when it is only rounding on each line.
Pick one rounding rule for line, tax and invoice totals. Apply it in billing and match it in the accounts.
Cancelled invoices that were never reversed
An invoice is cancelled at the counter and removed from billing. Its posting in Tally stays. The register now shows less than the books.
Cancelled documents should be recorded, not deleted. The cancellation then flows to the accounts the same way the original did.
Credit notes and returns with no parent invoice
When goods come back, some teams edit the original bill. Others post a credit note against nothing. Either way, the month becomes hard to rebuild.
Raise every return or rate correction as a credit note linked to the original invoice. Record the reason and handle the stock at the same time.
- Credit note linked to the original invoice
- Reason recorded on the note
- Stock movement posted with it
Entries that sit outside the register
Some invoices are raised in a marketplace panel or at a branch. If they never reach the posting job, they are missing from one side.
The opposite also happens inside Tally. TallyHelp notes that sales entries recorded in receipt or journal vouchers appear in GST returns but not in the Sales Register.
Its guidance also points to transactions flagged as mismatched, or as not relevant for returns. Check those lists before assuming an error.
Finding your cause, then keeping it found
Take one month. Export both sides with invoice number, date, taxable value and tax. Match them line by line.
Each unmatched line will fall into one of the causes above. Fix the process that made it, not only the entry.
Then compare billing with Tally every day. A gap found the next morning is far easier to explain than one found in filing week.
- Same invoice number on both sides
- Same date and taxable value
- Same tax split and ledger
- A stated reason for every difference left
Register-to-Tally match sheet
Two columns of invoices for one month, one from billing and one from Tally, matched by number. A third column records the cause of each mismatch. Share the finished sheet with your accountant.
Open a blank worksheet to printQuestions owners ask
Is the difference usually a wrong tax rate?
Rarely. Rates are applied the same way on both sides most of the time. Differences come from how documents are created, cancelled, returned or posted.
Will a monthly bulk upload into Tally solve this?
Not on its own. A bulk upload that nobody checks can carry the same errors across. A daily comparison report is what shows the gap.
Do we need to replace Tally to fix this?
No. Tally can stay where the books live. The fix is in how billing creates documents and how entries flow into the right ledgers.
Sources
- TallyHelp: GST FAQ (TallyPrime) — verified 6 Oct 2026