Financial Calculation Methodology
This page documents how FinCal Hub's calculators work, so you can verify any number independently.
Core formulas
| Calculator | Method |
|---|---|
| SIP / Step-up SIP / NPS / EPF | Future value of an annuity, monthly compounding: FV = P·[((1+i)ⁿ−1)/i]·(1+i). Step-up grows contributions annually. |
| Lumpsum / Compound interest | FV = P·(1 + r/n)^(n·t), with selectable compounding frequency n. |
| CAGR | (FV/PV)^(1/t) − 1. |
| EMI / amortisation | Reducing-balance EMI formula; month-by-month schedule with interest = balance·r, principal = EMI − interest. |
| Income tax | Slab-wise computation, standard deduction, 87A rebate, 4% cess. Surcharge and capital gains not modelled (stated on page). |
| PPF / SSY / NSC | Yearly (PPF/SSY) or half-yearly (NSC) compounding at the current notified rate; contribution windows per scheme rules. |
| GST | Add: base×(1+rate). Remove: total/(1+rate). Intra-state split CGST=SGST=rate/2; inter-state = IGST=rate. |
| Gratuity | (last basic × 15 × years) ÷ 26, per Payment of Gratuity Act; ₹20L tax-free cap for non-government employees. |
Assumptions we always state
- Constant returns / rates (real markets vary).
- Inflation is shown separately or excluded — never silently deducted.
- Tax is modelled only where the calculator says so; most investment calculators show pre-tax values.
- Fees, loads, stamp duty, processing charges and insurance premiums are excluded unless stated.
Verification & corrections
Each calculator is tested against known worked examples. If you find a discrepancy, email fincalhub.contact@gmail.com with the inputs and expected output; we will fix or explain within 7 days. Rate changes are tracked from official notifications (Ministry of Finance, EPFO, CBDT).