Professional Crossed 20 Laks in Dec 26 Failed to Take GST in 30 Days Taken GST in May 26

No. You cannot report the turnover of Dec-2025 to Mar-2026 in June-2026. GST is payable for the period in which the taxable supplies were actually made. If you crossed the threshold in Dec-2025, you should have applied for registration within the prescribed time, and the tax liability generally relates back to the effective date of registration/liability, subject to the registration order. The turnover of ₹7,63,800 should be considered for the relevant period itself. If GST was not collected from customers, it may have to be paid by you along with applicable interest and other consequences for delayed registration/compliance.

Thank You fro your reply sir ,

sir company  give gst reimbursement while filing the GSTR - 1 and GSTR -3B only thery are ready to pay the GST if we file the details in June 26  GSTR -1 & GSTR -3B for Jan 26 to March 26  with Invoice Dated 30.06.26

This situation has two parts: the penalty for late registration and the GST liability for the gap period.

GST liability for December to May:
Once you crossed Rs 20L, you were required to register within 30 days. From that point, all taxable supplies should have had GST applied even without registration. So you likely owe GST on all invoices raised from January (30 days after crossing in December) to the date of actual registration in May.

How to handle it:
- Compute all supplies made in the gap period
- Calculate GST due (typically 18% for professional services)
- Pay the tax plus interest at 18% per annum for the delay
- File a voluntary disclosure before the department issues a notice

Penalty for late registration:
Section 122 of the CGST Act applies: 10% of tax due or Rs 10,000, whichever is higher. Voluntary disclosure before any notice typically results in the lower end of the penalty scale.

The practical priority: compute and pay the gap-period tax now. Once that is done, the penalty becomes secondary.

For the full interest and late fee calculation framework, this [GST late fee and penalty guide](https://taxgarden.in/blog/gst-late-fee-interest-penalty-gstr-3b-gstr-1-gstr-9-guide) covers Sections 47 and 50 in detail.