CMP-08 in GST: meaning, due date, late fee, how to file and the RET00009 error

CMP-08 is the quarterly form in which a composition dealer declares their sales and pays their GST for the quarter. It is due by the 18th of the month after each quarter. The GST portal says there is no late fee for a late CMP-08, but you pay interest at 18% a year on tax paid late.

So CMP-08 for July to September 2026 was due on 18 October 2026, and CMP-08 for October to December 2026 is due on 18 January 2027. This guide explains who must file it, the due dates, the interest with examples, how to file it on the GST portal (including a nil CMP-08), what to do if you missed one, and how to deal with the RET00009 error.

What is CMP-08 in GST?

Form GST CMP-08 is a "Statement for payment of self-assessed tax". That is its official name in rule 62 of the CGST Rules. "Self-assessed" means you work out your own tax.

In CMP-08 you tell the government, for one quarter:

• the value of your sales (outward supplies), including exempt sales;
• the value of purchases on which you must pay tax yourself under reverse charge, including services imported from abroad;
• the tax on these, and any interest;

and you pay that tax from your electronic cash ledger at the same time. So CMP-08 is both a statement and a payment.

Composition dealers pay a low flat rate on their turnover: 1% for traders and manufacturers, 5% for restaurants and 6% for some service providers. Our GST composition scheme guide explains the scheme and the rates.

CMP-08 full form. CMP-08 has no official full form. "CMP" is the short name used for the composition forms (CMP-01 to CMP-08), and "08" is the form number. Our reading: read it as "Composition form 08".

Who must file CMP-08?

You must file CMP-08 if you are in the composition scheme. This includes:

• traders, manufacturers and restaurants who chose composition in the GST registration form (REG-01) or later by filing CMP-02;
• service providers paying 6% under the special scheme for small service businesses (section 10(2A), Notification 02/2019-Central Tax (Rate));
• composition dealers who had no sales in the quarter. They file a nil CMP-08.

Filing CMP-08 is mandatory for every quarter, even when you have no tax to pay. The GST portal FAQ says so in plain words.

You do not file CMP-08 if you are a regular GST taxpayer. Regular taxpayers file GSTR-1 and GSTR-3B instead.

If you join or leave the scheme in a quarter. Rule 62 says CMP-08 is filed for "every quarter or, as the case may be, part thereof". So:

• If you leave the scheme in the middle of a quarter (you opt out, or your turnover crosses the limit), file CMP-08 for the days you were in composition, by the 18th of the month after that quarter (rule 62(5)). From the day you leave, you file GSTR-1 and GSTR-3B. How to opt out is in our composition guide.
• If you were a regular taxpayer before, file your last GSTR-3B first. Otherwise the portal shows the error "You have not filed last tax period's return as a normal taxpayer" when you open CMP-08.

CMP-08 due date

The due date is the 18th of the month after the quarter. It is set by rule 62 of the CGST Rules.

The same four dates apply every year. You can file CMP-08 from the 1st of the month after the quarter ends.

Has the CMP-08 due date been extended? The government extended it a few times in 2019 and 2020, when the form was new and during COVID-19. We found no extension for any recent quarter, including July to September 2026, on 20 October 2026. If the date is extended, it is done by a notification, so check the news section of the GST portal before the 18th. All other GST due dates are on our GST return due dates page.

CMP-08 late fee and interest

There is no late fee for a late CMP-08. The GST portal FAQ asks "Is there any late fee in case of delayed filing of Form GST CMP-08?" and answers "No, there is no late fee for delayed filing of Form GST CMP-08." GSTN's self-service help page says the same.

Some websites say the CMP-08 late fee is ₹200 a day, up to ₹5,000. That is not what the GST portal says. Our reading: late fee under section 47 is for returns, and CMP-08 is a statement for paying tax, so it carries interest instead.

Interest is payable. The form itself says "Interest shall be leviable if payment is made after the due date." Under section 50 of the CGST Act, interest is 18% a year on the tax you paid late, counted from the day after the due date to the day you pay.

Example 1. A grocery shop in the composition scheme has ₹12,000 of tax for July to September 2026. It missed the 18 October 2026 date. If it pays on 28 October 2026, it is 10 days late. Interest: ₹12,000 x 18% x 10 / 365 = about ₹59. No late fee.

Example 2. The same shop has ₹30,000 of tax for October to December 2026, due on 18 January 2027. If it pays on 17 February 2027, 30 days late, the interest is ₹30,000 x 18% x 30 / 365 = about ₹444. If it pays on 18 January 2027, it pays no interest.

How interest works in CMP-08:

• CMP-08 has a row for "Interest payable, if any". Our reading: you work out the interest and enter it there. Our GST interest calculator (choose "interest only") gives the figure.
• You pay the tax and interest together, in cash. The GST portal says CMP-08 tax "can be paid only through cash and not through ITC".
• A nil CMP-08 has no tax, so it has no interest, even if filed late.

How to file CMP-08 online

Before you start: keep your total sales for the quarter ready, rate by rate, and the value of any purchases on which you pay reverse charge. File any older CMP-08 first; the portal needs every earlier quarter to be filed. There is no offline tool for CMP-08, so you fill it online.

1. Log in at www.gst.gov.in.
2. Go to Services, Returns, Returns Dashboard.
3. Choose the Financial Year and the Return Filing Period (the quarter), and click SEARCH.
4. In the GST CMP-08 tile, click PREPARE ONLINE.
5. Enter your details in Table 3 and click SAVE, then OK.
6. Click PREVIEW DRAFT GST CMP-08 to download a PDF and check it.
7. Click PROCEED TO FILE and then OK.
8. On the Payment of Tax page, look at the Cash Ledger Balance. If the Additional Cash Required column shows an amount, click CREATE CHALLAN, choose how to pay (E-Payment, Over the Counter or NEFT/RTGS), click GENERATE CHALLAN and pay it. Then come back to the Returns Dashboard and check that Additional Cash Required shows Nil.
9. Tick the declaration and choose the Authorised Signatory.
10. Click FILE GST CMP-08 and then YES.
11. Click FILE WITH DSC, FILE WITH EVC (a one-time password sent to the signatory's mobile and email) or FILE WITH STAK (a code from the "GST Secure OTP" mobile app).

After filing, you see the ARN and the status changes from "Not filed" to "Filed". To download the filed form, click DOWNLOAD FILED GST CMP-08. For a signed PDF, click DOWNLOAD and then GENERATE SIGNED PDF OF FILED CMP 08; it can take up to 5 minutes.

Two things the portal checks:

• Turnover limit. If your turnover for the current year, up to this quarter, is above the composition limit (₹1.5 crore, ₹75 lakh in 8 States, or ₹50 lakh for 6% service providers), the portal does not let you file until the mismatch is sorted out. At 80% of the limit, you get an alert under My Alerts.
• DSC type. The portal accepts only a PAN based Class III DSC.

How to pay into your cash ledger is explained step by step in our guide on how to pay GST online.

How to file a nil CMP-08

File a nil CMP-08 when you have no tax to pay for the quarter: no sales, and no purchases on which you pay reverse charge. The form's own instruction says "'Nil' Statement shall be filed if there is no tax liability due during the quarter."

Do steps 1 to 4 above, then tick File Nil GST CMP-08 and continue from step 6. Do not try to save Table 3 with all zeros; the portal shows an error and does not save it. Use the nil tick box instead.

You can also file a nil CMP-08 by SMS, without logging in. The message format and the conditions are in our nil return guide.

What is in Form CMP-08

For each row, you give the value and the tax under Integrated tax, Central tax, State or UT tax, and Cess. Composition dealers usually have only Central tax and State or UT tax (half each).

• Adjustments. Advances, credit notes, debit notes and corrections are adjusted against the tax. If the total comes out negative, it is carried forward to your next CMP-08, where it shows as "Adjustment of negative liability of previous tax period".
• Sales split. For recent quarters, the portal splits the sales row into three lines (1, 1a and 1b). For older quarters it is one line. Fill what the screen shows.
• If the tax you enter is more than the value, the portal shows "Taxable value should be greater than tax amounts".

Missed a CMP-08? What happens, and how to file it late

If you missed a CMP-08, file it as soon as you can. There is no late fee, but the interest grows every day. Missing it also blocks other things:

1. Your next CMP-08 waits. The portal lets you file a CMP-08 only after all earlier quarters are filed.
2. Your GSTR-4 is locked. The yearly GSTR-4 opens only after all four CMP-08s of the year are filed. GSTR-4 has its own late fee (₹50 a day, up to ₹2,000) once 30 June passes.
3. E-way bills can be blocked. If a composition dealer has not filed for two tax periods in a row, the portal can stop them from making e-way bills (rule 138E).

To catch up, file the oldest pending CMP-08 first, pay the tax and interest, and then the next one.

Is there a time limit for an old CMP-08? The 3-year limit in section 39(11) is for returns, and GSTN's list of blocked forms does not include CMP-08. Our reading: an old CMP-08 is not blocked by time. But the GSTR-4 for that year is. GSTR-4 for FY 2023-24 can be filed only until 30 April 2027, so any CMP-08 missing for 2023-24 must be filed before that.

Made a mistake in a filed CMP-08?

You cannot revise a CMP-08 once it is filed. The GST portal FAQ says "Form GST CMP-08 once filed, cannot be revised."

What you can do:

• You paid too little. Our reading: add the missed amount in your next CMP-08 as an adjustment, and pay interest on it from the original due date. The form says rectifications "shall be reported against the liability".
• You paid too much. Report the adjustment in the next CMP-08. If the total becomes negative, it is carried forward and used in the next quarter.
• At the year end, your GSTR-4 shows your full sales for the year. It should match your four CMP-08s, or the portal shows the difference.

RET00009 error in CMP-08

Many people see this message when they click to file CMP-08:

"Return already under process. If error persists, quote error number RET00009 when you contact customer care for quick resolution."

What it means. Tax websites and users report that RET00009 shows when the portal is still processing an earlier request for the same form, and you try to submit again. It is a portal-side issue, not a mistake in your figures. GSTN has not published an explanation of RET00009 that we could find, so this is based on those reports.

How to fix RET00009, step by step:

1. Do not click again and again. Each new click can be another request.
2. Check if it was filed. Open Services, Returns, Returns Dashboard, choose the quarter and look at the CMP-08 status. If it says "Filed", or you got an ARN by SMS or email, you are done.
3. Check your cash ledger. If the tax was already taken from your electronic cash ledger, do not pay it again.
4. Wait and try again later. Most reports say to wait up to a day and then file again.
5. If it still shows, call the GST helpdesk on 1800-103-4786 (toll free), or raise a ticket on GSTN's self-service portal (selfservice.gstsystem.in) using Report Issue. Attach a screenshot of the error and note the date and time.

File early. If you see RET00009 on the due date and it clears only the next day, interest still applies to the tax paid late. Filing a few days before the 18th avoids this.

The same RET00009 message can appear in other forms, such as GSTR-4 and GSTR-9. For GSTR-9, see our guide on how to file GSTR-9.

Other CMP-08 errors and fixes

CMP-08 vs GSTR-4 vs GSTR-3B

Read more in our GSTR-4 guide.

Frequently asked questions