Glossary
What is a lock date?
Once a month is closed and its return is filed, its figures should not move. A lock date makes sure they cannot.
Updated
In short
A lock date is the date on or before which no transaction can be added, changed or cancelled. In SimpleERP the database itself refuses any posting dated on or before the lock date, and moving it back needs its own permission.
A lock date is the date on or before which no transaction can be added, changed or cancelled in the books. Accountants set it after closing a month or filing a return, so figures already reported cannot shift because of a late correction. Anything that needs changing is then recorded in an open period instead, which keeps reported figures and the books in agreement.
Lock date: a worked example
Lakshmi Steel Furnitures files its September GSTR-3B on 20 October 2026, then locks the books through 30 September.
| Date | What happens | Result |
|---|---|---|
| 20 Oct 2026 | Lock date set to 30 Sep 2026 | September is closed |
| 24 Oct 2026 | An overcharge of ₹1,000 plus ₹180 GST is found on a 28 Sep invoice to Sri Murugan Traders | Cancelling or editing the invoice is refused |
| 24 Oct 2026 | Credit note for ₹1,180 dated 24 Oct | Posts in October; September stays as filed |
FAQ
Questions, answered
When should I move the lock date forward?
After each month's figures are final: bank checked, GST return filed, stock counted if you count monthly. Many businesses lock the previous month once GSTR-3B is filed. Locking promptly stops back-dated entries from changing what you have already reported.
What if I find an error in a locked month?
Record the correction in the current open period, such as a credit note or a reversing journal dated today. If the earlier period truly must change, someone with permission moves the lock date back, posts the fix and locks again, and the change is logged.
Does a lock date stop people from viewing old records?
No. Reports, invoices and the ledger for locked periods can still be read, printed and exported. The lock only stops postings, edits and cancellations dated on or before it, so the record stays complete.
Is a lock date the same as closing the financial year?
Locking 31 March freezes the year, which is most of what closing means. In software that carries profit into retained earnings automatically, no separate closing entry is needed, so setting the lock date is the year-end close.
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