Each guide explains the method behind a calculator: the formula, a worked example with real numbers, the rules that change the answer, and where to check the official source. The calculators give you the number; the guides explain why.
GST 2.0: What Got Cheaper and What Got Costlier
Which items moved to 0%, 5%, 18% or 40% after 22 September 2025, with worked price examples and the maximum price change you can expect.
Gratuity Calculation: Formula, 5-Year Rule and Worked Examples
The 15/26 formula, the 5-year rule, the 4 years 240 days question, the new 1-year rule for fixed-term staff and the Rs 20 lakh tax limit.
ICSE and ISC Percentage: How to Calculate It
English plus best four (ICSE) or best three (ISC), PCM and PCB aggregates, and the mistakes that give the wrong percentage.
Home Loan Prepayment: How Much Interest You Actually Save
What a Rs 5 lakh prepayment saves in year 1, 5 or 10 on a Rs 30 lakh loan, reduce tenure vs reduce EMI, and the RBI prepayment rule.
How we write and update guides
- Written and reviewed by one named person. Every guide carries the author name and a visible last-updated date. See the About page.
- Official sources first. Rates, limits and rules are checked against the GST Council, the Ministry of Labour, the RBI, CISCE and the Income Tax Department, and linked at the bottom of each guide.
- Numbers you can reproduce. Every example shows its inputs and its formula, so you can repeat it on the matching calculator.
- Updated when rules change. If a rate, limit or rule changes, the guide and the calculator are updated together and the date is changed.
- Corrections welcome. If you spot a mistake, use the Contact page and we will check it and fix it.
Guides are general information, not legal, tax or financial advice. Please confirm with the official source or a qualified professional before making a decision.