Section 59 states the basic rule of GST: the taxpayer assesses its own tax. The department does not assess routinely; it scrutinises, audits and investigates, and determines tax only where the self-assessment is shown to be wrong.
Key points
- Under section 59 of the CGST Act, 2017 every registered person self-assesses the tax payable under the Act and furnishes a return for each tax period under section 39.
- Self-assessment is the starting point for scrutiny (section 61), audit (sections 65–66) and demands (sections 73, 74 and 74A); best-judgment and summary assessments (sections 62–64) are the exceptions.
- Because the return is the taxpayer's own assessment, errors are corrected forward in later returns, not by reopening past ones (section 39(9); Union of India v Bharti Airtel, SC 2021).
The provisions
59Self-assessment
Statutory text
Every registered person shall self-assess the taxes payable under this Act and furnish a return for each tax period as specified under section 39.
*Enforced w.e.f. 1st July, 2017.
Statutory text as published on the CBIC tax information portal, as on 03.10.2026; the numbered notes record each amendment. Official source
Common questions
- Is GST self-assessed?
- Yes. Section 59 of the CGST Act requires every registered person to self-assess its tax and file returns under section 39; the department verifies through scrutiny, audit and investigation.
Commentary and case notes checked against the judgments and CBIC sources on 04.10.2026.
What it means
Self-assessed tax that is declared but not paid can be recovered directly under section 75(12), without a show cause notice. Tax not declared at all must be determined under section 73, 74 or 74A. The Supreme Court in Union of India v Bharti Airtel (2021) relied on the self-assessment scheme to hold that a taxpayer cannot reopen its own past returns — see section 39(9).