Methodology
Show your working
Wrong tax or EMI math destroys trust, so we don't hide ours. Here's exactly how every number is calculated and where the rules come from. Every formula is unit-tested.
Quick answer
MoneyRadar uses standard financial formulas cited to official Indian sources: Income Tax Department for FY 2025-26 slabs, RBI for EMI reducing-balance math, EPFO/NSI for PPF/SSY rates, and AMFI for SIP conventions. Every calculator is unit-tested and carries a last-checked date on rate-dependent pages.
Income tax & salary
We apply the FY 2025-26 (AY 2026-27) slabs for both regimes, the standard deduction (₹75,000 new / ₹50,000 old), the Section 87A rebate (tax-free up to ₹12L taxable in the new regime, ₹5L in the old), 4% health & education cess, and surcharge tiers for high incomes. CTC-to-take-home uses transparent, stated assumptions (Basic = 50% of CTC, EPF at 12%, gratuity provision at 4.81% of basic, professional tax ₹2,400/yr) — every assumption is shown so you can adjust it.
Loans & EMI
All EMIs use the standard reducing-balance formula: EMI = P·r·(1+r)ⁿ / ((1+r)ⁿ−1). Total interest is EMI × months − principal. Prepayment impact is simulated month by month against the original schedule. Loan eligibility uses a FOIR (fixed-obligations-to-income) cap of ~50%.
Investing (SIP, lumpsum, step-up, CAGR)
SIPs are modelled as monthly annuities compounded monthly. Step-up SIPs grow the contribution annually. Lumpsum uses annual compounding. CAGR = (End/Begin)^(1/years) − 1. Return assumptions are just that — assumptions. Markets are volatile and past performance never guarantees future returns.
Small savings (PPF, SSY, EPF, FD, RD)
PPF and SSY use the government-declared rates with annual compounding and their statutory lock-ins (PPF 15 years; SSY deposits 15 years, matures at 21). EPF compounds contributions (12% employee + ~3.67% employer share) at the declared EPF rate. FDs compound quarterly by default; RDs are modelled as monthly annuities.
Product comparisons (cards, insurance, loans, deposits)
Comparison data is a curated, point-in-time snapshot. Every product carries a 'verified on' date, and anything past our freshness window is flagged. Rankings are driven by the metric that decides your outcome — claim settlement ratio for insurance, effective rate for loans, everyday rewards-minus-fee for cards — never by commercial arrangements.
Found an error?
We'd genuinely rather know. If a number looks off or a rule has changed, tell us and we'll fix it fast — accuracy is the whole point. In the meantime, always verify current rates and rules with the official source before acting.
More about how we work → · Editorial standards →Common questions
- Where does MoneyRadar get its tax and EMI formulas?
- From official sources: Income Tax Department and Union Budget for tax slabs, RBI for loan rules, EPFO/NSI for PPF/EPF rates, and AMFI for investing conventions. Every formula is unit-tested.
- How often are calculator rates updated?
- Tax rules are updated after each Union Budget. Small savings rates (PPF, SSY) are reviewed quarterly. Product comparison data carries a visible 'verified on' date and is flagged when stale.