GST Late Payment Interest Calculator

Late GST payment attracts interest at 18% per annum (simple interest) under Section 50 of the CGST Act. Unlike penalties which are discretionary, interest is mandatory and automatically charged by GSTN. The interest accrues daily from the due date (20th of next month for normal taxpayers) until the date of payment. Even a single day of delay triggers interest calculation. For small businesses with cash flow constraints, interest charges can quickly become significant. Example: A ₹1 lakh GST liability paid 30 days late incurs ₹1,479 in interest. Over a year, recurring delays compound substantially. Interest cannot be claimed as input credit or business expense, making it a dead-loss cost. Many businesses fail to factor interest into their GST planning, resulting in higher-than-expected tax costs. The GST department rarely waives interest except for genuine system failures or force majeure events. This calculator helps forecast the true cost of delayed payment and motivates timely compliance.