CMP-08 Due Date
CMP-08 is due on the 18th of the month following the end of each quarter.
Quick answer
Next due date
18 October 2026
Pattern
18th of the month after quarter end
The composition scheme's recurring quarterly filing
CMP-08 is a statement-cum-challan — it declares the composition dealer's quarterly turnover and simultaneously pays the tax due, functioning as both a return and a payment instrument in a single filing. It's due by the 18th of the month following each quarter's end, giving composition dealers four filings a year rather than the regular scheme's twelve (GSTR-1 and GSTR-3B combined) or the QRMP scheme's mixed monthly-and-quarterly cadence.
Because CMP-08 combines the declaration and the payment, there's no separate tax-payment deadline to track the way QRMP filers track PMT-06 — missing the 18th means both the statement and the payment are late simultaneously.
How CMP-08 feeds into GSTR-4
The four CMP-08 filings made across a financial year form the raw material for the composition dealer's annual GSTR-4 — rather than reporting fresh figures, GSTR-4 largely consolidates what's already been declared quarterly through CMP-08, along with a small amount of additional information like inward supplies liable to reverse charge. Keeping each quarter's CMP-08 accurate makes the year-end GSTR-4 close to a formality; errors carried across multiple quarters are what typically complicate the annual filing.
A composition dealer filing CMP-08 slightly incorrectly in one quarter — understating turnover, for instance — carries that error forward into three more quarters before GSTR-4 forces a reconciliation, by which point correcting it retroactively is considerably more work than catching it in the quarter it happened.
Frequently asked questions
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See PracticeFlow for CA FirmsVerified for FY 2026-27 · Last updated 8 July 2026.
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