Methodology
This page explains how Calcnomy's finance calculators work, what they assume, and what they can't tell you. Most calculator pages also explain their own method and give worked examples.
Standard formulas
Calculators use standard, published methods. Two examples:
- Loan EMI uses the reducing-balance formula used by Indian banks: EMI = P × r × (1 + r)n ÷ ((1 + r)n − 1), where P is the loan amount, r is the monthly interest rate (annual rate ÷ 12 ÷ 100) and n is the number of monthly instalments.
- SIP maturity uses the future value of monthly investments made at the start of each month: FV = P × ((1 + r)n − 1) ÷ r × (1 + r), where P is the monthly investment, r is the expected monthly return (annual rate ÷ 12 ÷ 100) and n is the number of months.
Tax rules and scheme rates
- Income tax: the income tax calculator covers FY 2025-26 (AY 2026-27) and Tax Year 2026-27, under both the new and old regimes.
- Government scheme rates such as PPF and Sukanya Samriddhi are set by the government and can change every quarter. Each calculator shows the rate it uses, and you can change it to the current rate.
To confirm a rule or rate, check the official source:
- Income tax: Income Tax Department (incometax.gov.in)
- GST: Central Board of Indirect Taxes and Customs (cbic.gov.in)
- Small savings schemes (PPF, SSY, NSC, SCSS): Ministry of Finance notifications and India Post
- NPS: Pension Fund Regulatory and Development Authority (pfrda.org.in)
- EPF and EPS: Employees' Provident Fund Organisation (epfindia.gov.in)
- Loan rates: your bank or lender's published rates
What the calculators assume
- Loans: a fixed interest rate for the full term, with no fees or prepayments unless you add them.
- Investments: a constant rate of return. Real market returns go up and down, so treat projections as illustrations, not forecasts.
- Rounding: results may be rounded for readability, so they can differ from a bank statement by a few rupees.
- Your inputs: a result is only as accurate as the figures you enter.
Who checks the calculators
Calcnomy's calculators and guides are not reviewed by a chartered accountant, CFA or other licensed professional. When you report an error, we check it and correct it if it is confirmed.
Estimates, not advice. Use the results to plan and compare. Actual bank offers, charges, scheme rates and tax outcomes can differ, so confirm final figures with your bank, employer or a chartered accountant before you commit.
Privacy
Calculations run in your browser. The figures you enter are not stored on our servers. See the privacy policy for details.
Report an error
Email contact@calcnomy.com with the calculator name, the figures you entered, the result you got and the result you expected (with a source if you have one).