Official sources we use
The rules our calculators and guides apply, such as tax slabs, scheme interest rates, gratuity limits and GST invoice rules, come from the documents below. Each link opens the document on the publisher's own website: the Gazette of India, a ministry, a regulator or an exam body.
Income tax
- Income Tax Department — official e-filing portal
- Income Tax Department — guide for salaried taxpayers
- Cost Inflation Index notified by CBDT
- Gazette of India — Income-tax Act, 2025 (full text)
- Gazette of India — Finance Act, 2026 (No. 4 of 2026)
- Income Tax Department — Tax Payments FAQ (e-Pay Tax, tax year to select)
- Union Budget of India
- Income Tax Department — e-Pay Tax
- PIB — tax-free gratuity limit raised to ₹20 lakh (7 March 2019)
GST
- CBIC — GST rates for goods and services
- GST Council — rate notifications and press releases
- GST — official taxpayer portal
- CBIC — CGST Rules, rule 46: what a tax invoice must contain
- CBIC — CGST Rules, rule 47: invoice a service within 30 days
- CBIC — CGST Rules, rule 48: invoice copies and e-invoicing
- CBIC — IGST Act, section 12: place of supply of services
- CBIC — IGST Act, section 2(6): export of services
- CBIC — CGST Act, section 22: when GST registration is required
- GST portal — filing a Letter of Undertaking (Form GST RFD-11)
- GST portal — HSN/SAC digits by turnover (Notification 78/2020-CT)
- GST e-Way Bill system — state code list
- CBIC — frequently asked questions on GST
- CBIC — Notification 11/2017-Central Tax (Rate): GST rates on services
Salary, PF, gratuity and pay commission
- EPFO — Employees' Provident Fund Organisation
- Gazette of India — Code on Social Security, 2020 (full text)
- Gazette notification S.O. 5319(E), 21 November 2025 — Code on Social Security in force
- Ministry of Labour and Employment — FAQs on Labour Codes (30 December 2025)
- Ministry of Labour and Employment — Additional FAQs on Labour Codes (16 March 2026)
- Ministry of Labour and Employment
- PIB — DA raised to 60% from 1 January 2026
- PIB — terms of reference of the 8th Central Pay Commission
- 8th Central Pay Commission — official website
- Department of Expenditure — DA, HRA and transport allowance orders
- Labour Bureau — CPI for Industrial Workers, the index DA is set from
- Gazette of India — EPF Scheme, 2026: corrigendum G.S.R. 703(E), 4 August 2026
- PIB — EPF interest rate recommended for 2025-26 (239th CBT meeting)
- PIB — fact sheet on the Labour Codes (22 November 2025)
- PIB — central government gratuity ceiling raised to ₹25 lakh from 1 January 2024
Pensions: NPS, APY and UPS
- PFRDA — pension regulator
- NPS Trust — scheme details and returns
- Atal Pension Yojana — official scheme page
- PFRDA — Unified Pension Scheme
- Department of Financial Services — FAQs on the Unified Pension Scheme
- PIB — one-time switch from UPS to NPS
- PFRDA — press release on the changes to NPS exit and withdrawal rules
- PFRDA — NPS for all citizens
Small savings schemes
- India Post — small savings schemes
- National Savings Institute — small savings interest rates
- National Savings Institute — Senior Citizens' Savings Scheme, 2019 (scheme rules)
- National Savings Institute — Monthly Income Account Scheme, 2019 (scheme rules)
- India Post — SB Order 09/2021, MIS interest credited to your bank account
- Gazette of India — Mahila Samman Savings Certificate, 2023 (G.S.R. 237(E))
- National Savings Institute — Form-1, account opening application
- National Savings Institute — Government Savings Promotion General Rules, 2018
- Department of Economic Affairs — quarterly small savings rates
- Department of Economic Affairs — small savings interest rate notices
- National Savings Institute — Kisan Vikas Patra
- National Savings Institute — Kisan Vikas Patra Scheme, 2019 (scheme rules)
Banks, loans and deposits
Investing and insurance
Exports and foreign exchange
- RBI — FEMA (Export and Import of Goods and Services) Regulations, 2026 (FEMA 23(R)/2026-RB)
- RBI — Amendment of 22 September 2026 cutting the realisation period to 9 months
- RBI — Export Declaration Form (EDF), Annex to the 2026 Regulations (PDF)
- RBI — Master Direction on Export of Goods and Services
- DGFT — Importer Exporter Code (IEC)
Electronic signatures and data protection
Photo and signature rules for exam applications
- IBPS — guidelines for scanning the photograph and signature (March 2026)
- SSC — Constable (GD) Examination 2026 notice (1 December 2025)
- SSC — Sub-Inspector in Delhi Police and CAPFs Examination 2026 notice
- SBI — recruitment advertisement CRPD/RS/2026-27/08 (May 2026)
- UPSC — CAPF (Assistant Commandants) Examination 2026 notice
- UPSC — One Time Registration FAQs
- NTA — NEET (UG) 2026 Information Bulletin
- NTA — UGC-NET December 2026 Information Bulletin
Other official sources
Questions about our sources
Why does this page exist?
So you can check any number on this site against the law it comes from. A calculator applies a tax slab, a scheme rate or a limit, and the documents on this page are where those come from.
How do you keep these sources up to date?
We re-check a rule when the law behind it changes: the Union Budget and Finance Act each year, the quarterly notice on small savings rates, the yearly EPF interest rate, and new labour, GST, RBI or PFRDA notifications. Income tax follows the Income-tax Act, 2025, which applies from 1 April 2026.
Why is a source cited on a calculator missing here?
This page lists only documents on the publisher's own website. Where we could find a rule only in a copy published by someone else, the calculator may cite that copy, but it stays off this page until we find the official text.
What if a calculator does not match a source?
The official text prevails. Tell us through the contact page, naming the calculator and the source, and we will check it.
Is this list legal or tax advice?
No. It shows where the rules come from. How a rule applies to you can depend on details a calculator does not ask, so for a decision read the source or ask a chartered accountant or tax adviser.