A practical walkthrough of India's two main GST returns: what GSTR-1 and GSTR-3B are, when they're due, how to file them on the GST portal, and the mistakes that trigger notices.
Scholarships of up to 30% are available via the free CELSE scholarship test. Call +91 8007 980 000 for current fees.
Two centres in Kerala: Kochi (Edappally) — +91 8007 980 000 · Kozhikode (Mavoor Road) — +91 7902 517 000.
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GSTR-1 reports the details of your outward supplies (sales) invoice by invoice. GSTR-3B is a monthly summary return where you declare total sales, claim input tax credit (ITC) and actually pay the tax. GSTR-1 feeds your buyers' GSTR-2B, which is why filing it accurately and on time matters to your customers too.
For monthly filers, GSTR-1 is generally due on the 11th of the following month and GSTR-3B on the 20th. Small taxpayers under the QRMP scheme file both quarterly (with monthly tax payment). Always confirm current dates on gst.gov.in, as the government occasionally revises them.
Late filing attracts a late fee per day (CGST + SGST) plus 18% annual interest on unpaid tax. Persistent non-filing can lead to e-way bill blocking and even GSTIN suspension. Buyers may also lose ITC visibility, which damages business relationships.
GSTR-1 and GSTR-3B cannot be revised once filed. Corrections are made in subsequent periods through amendments (for GSTR-1) or adjustments (for GSTR-3B). This is exactly why accountants double-check data before submitting.
CELSE Labs' Certified Accounting Professional (CAP) program in Kochi and Kozhikode covers GST end-to-end — registrations, invoicing, GSTR-1/3B filing, e-invoicing with IRN generation, and reconciliation — practised hands-on on simulated companies with a full year of transactions.
CELSE Labs — the Centre for Experiential Learning and Skill Enhancement — is an NSDC-certified, ISO 9001:2015 accredited skill training institute and an Approved Training Partner of Medhavi Skills University. We work with commerce graduates, career changers and working professionals across Kerala who want a job in accounting, finance, compliance or data, and who need practical capability rather than another certificate.
Our training is experiential rather than lecture-based. Instead of textbook exercises, trainees operate the books, bank account, invoices and internal correspondence of simulated companies — M & M Technologies, Toy Kingdom and PetalSoft — where transactions arrive incomplete, out of order and occasionally wrong, exactly as they do in a real office. Trainees learn judgement by making decisions and correcting them, which is the part of the work that cannot be transferred by explanation.
Teaching is one-to-one, so pace follows the learner rather than a cohort. New batches start every Wednesday at both centres. Scholarships of up to 30% are available through a free online scholarship test, and our placement record includes 36+ named alumni at HDFC, ICICI, Bajaj Finserv, Kotak Mahindra, Big Basket, Ford, Amrita Hospital and JRHA Accounting in the UAE.
Visit us at Edappally in Kochi or Mavoor Road in Kozhikode, or call +91 8007 980 000 to arrange a free counselling session.