About Our Data — Methodology & Sources

RupayWise provides 36 financial calculators and 5 live data pages covering tax, investments, real estate, and financial planning in India. Every number on this site is traceable to an official source. This page explains how we collect, verify, and update our data.

Who Builds RupayWise

RupayWise is built by Ganesh Kompella, Founder & CTO of Kompella Tech Pvt. Ltd. Ganesh holds the NISM Series XIX-C: Alternative Investment Fund Managers Certification from the National Institute of Securities Markets (NISM), a SEBI body. This certification covers portfolio management, risk analysis, and regulatory compliance for investment products in India. Every calculator formula and data interpretation on RupayWise is reviewed by Ganesh before publication.

Primary Data Sources

Reserve Bank of India (RBI)

Repo rate, reverse repo rate, CRR, SLR, and monetary policy data. Used in home loan rate calculations, FD rate context, and inflation analysis. Source: rbi.org.in

Income Tax Department

Tax slab rates, Section 80C/80D limits, HRA rules, capital gains tax rates, and standard deduction amounts. Source: incometaxindia.gov.in

AMFI (Association of Mutual Funds in India)

SIP account data, monthly inflow figures, NAV data, and mutual fund industry statistics. Source: amfiindia.com

SEBI (Securities and Exchange Board of India)

Expense ratio regulations (TER circular), mutual fund categorization norms, and NPS guidelines. Source: sebi.gov.in

MOSPI (Ministry of Statistics)

CPI inflation data (base year 2012=100), WPI data, and historical inflation rates. Source: mospi.gov.in

NSE Indices & BSE

Nifty 50 TRI historical data for equity return benchmarks, PE ratio data for market valuation context. Source: niftyindices.com

State Government Registries

Stamp duty rates and registration charges for 10 states, sourced from individual state IGR (Inspector General of Registration) websites and gazette notifications.

How We Update Data

RupayWise uses automated data pipelines built on n8n (workflow automation) that run on a scheduled basis:

  • •RBI repo rate is checked after every MPC meeting (6 times per year) and updated within 24 hours of announcement.
  • •PPF rate is checked quarterly when the Ministry of Finance announces small savings rates.
  • •FD & home loan rates are verified from bank websites after every RBI rate change.
  • •Tax slab rates are updated annually after the Union Budget (February) and verified against the Finance Act.
  • •Stamp duty rates are reviewed quarterly and updated when state government notifications change rates.

When automation detects a data change, it updates our database (Supabase) and conditionally triggers a site rebuild on Vercel to ensure pages reflect the latest rates.

Calculator Methodology

All calculators use standard financial formulas (future value of annuity, compound interest, amortization schedules) implemented in TypeScript with full test coverage. Key methodological notes:

  • •SIP Calculator: Uses FV of annuity formula with expense ratio deducted from gross return before compounding. LTCG computed at 12.5% on gains above ₹1.25 lakh/year.
  • •Tax Regime Comparator: Implements both Old and New regime slab structures with all applicable deductions (80C, 80D, 80CCD, HRA, LTA, home loan interest). Includes surcharge and cess calculation.
  • •Rent vs Buy Calculator: Net present value comparison of renting vs buying with property appreciation, rent inflation, EMI amortization, tax benefits, and opportunity cost of down payment.
  • •Stamp Duty Calculator: State-specific rate tables with gender-based and registration type variations for 10 states, based on the latest gazette notifications.

Each calculator page includes a “Methodology” section explaining its specific formula, assumptions, and limitations.

Limitations & Disclaimer

RupayWise calculators provide estimates for educational and planning purposes. They do not constitute financial, tax, or legal advice. Key limitations:

  • •Default return rates are based on historical averages and do not predict future performance.
  • •Tax calculations may not cover every edge case (e.g., special provisions for senior citizens, agricultural income, or NRI-specific rules).
  • •Stamp duty and registration charges may vary by local municipal body within a state.
  • •Always verify numbers with official sources and consult a SEBI-registered financial advisor before making investment decisions.

Report a Data Error

Found an outdated rate or calculation error? Email us at hello@rupaywise.com with the page URL and the correct figure. We typically verify and fix reported errors within 24 hours.