Data Sources & Citations
We take every number from a primary source so you can trust the results. Inflation rates come from national statistics agencies, and tax brackets come from official tax authorities. Here is exactly where each one comes from.
1. Inflation Indices (CPI baselines)
Default inflation rates are long-run trailing averages (roughly a 10-year window through the last full calendar year), not the current headline rate. Short-term spikes even out over the 20 to 30 years these calculators model. Each rate comes from the official national index:
- United States: U.S. Bureau of Labor Statistics CPI-U. bls.gov/cpi
- India: Ministry of Statistics & Programme Implementation (MoSPI), CPI (Combined). mospi.gov.in
- United Kingdom: Office for National Statistics, Consumer Prices Index. ons.gov.uk
- Canada: Statistics Canada, Consumer Price Index. statcan.gc.ca
- Australia: Australian Bureau of Statistics, CPI. abs.gov.au
- Europe: Eurostat, Harmonised Index of Consumer Prices (HICP). ec.europa.eu/eurostat
Inflation defaults last verified: June 2026.
2. Tax Schedules & Bracket Rules
Income tax structures are updated annually according to regional revenue guides:
- United States: Internal Revenue Service, annual tax-year brackets. irs.gov
- India: Income Tax Department / Ministry of Finance, FY 2025-26 slabs (new & old regime). incometax.gov.in
- United Kingdom: HM Revenue & Customs, Income Tax rates & PAYE. gov.uk/income-tax-rates
- Canada: Canada Revenue Agency, federal and provincial rates. canada.ca
- Australia: Australian Taxation Office, resident individual rates. ato.gov.au
- Europe: OECD Tax Database, consolidated national averages. oecd.org
Tax schedules last verified: June 2026. Brackets are updated once a year, not in real time, so confirm against the official source before filing.
3. Investment Return Assumptions
Default equity-return rates are long-run historical averagesfor each market's broad index, used only as a planning baseline. They are assumptions, not guarantees, and you can change every rate in the calculator. References include each market's benchmark index history (e.g. S&P 500 for the US, FTSE All-Share for the UK, Nifty 50 for India) and long-term capital-market assumptions published by major asset managers.
Past performance does not predict future returns. Real (inflation-adjusted) outcomes will differ from these baselines.