Invoice Date vs Due Date vs Supply Date: What Each Actually Means for GST Timing

An invoice can legitimately carry several different dates at once, and each one does a different job. Confusing them isn't just sloppy — it can put an invoice in the wrong numbering year or the wrong GST return period.

Invoice date

The date the invoice itself is issued. This is what determines which financial year's numbering sequence the invoice belongs to, and which GST return period it gets reported in — not the date the work was done or the date payment arrives.

Date of supply (time of supply)

Under GST, "time of supply" is a specific legal concept that determines when tax liability actually arises — it's generally tied to whichever happens earliest among the invoice being issued, payment being received, or the goods/service actually being supplied, with specific rules depending on the transaction type. This is the date that actually governs which tax period you owe GST for, and it doesn't always match the invoice date exactly, particularly around month-end and for advance payments.

Due date

Purely a commercial term — when you expect payment, based on your agreed credit terms. It has no direct GST-return significance; it only affects your own receivables tracking and, if unpaid long past it, your party ledger and collections process.

Why the mix-up actually matters

An invoice dated in one financial year but reported in a return for a different period is exactly the kind of mismatch that surfaces later, usually during a GSTR-1/GSTR-3B reconciliation rather than immediately. The fix isn't complicated — it's just discipline about which date belongs in which field, applied the same way every time an invoice is created.