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Inflation Calculator — Indonesia & United States

What's Rp 1,000,000 in 1990 worth today? How about $100 in 2000? This calculator uses official YoY CPI data from Badan Pusat Statistik (Indonesia) and the US Bureau of Labor Statistics to give you the equivalent in today's money — or any year you choose.

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Cumulative inflation since the start date

How many times prices have risen since your start date. Indonesia in blue, United States in orange.

How the inflation calculator works

Inflation erodes the purchasing power of money over time. A candy bar that cost $0.10 in 1970 now costs well over a dollar — not because the candy changed, but because the dollar did. This tool quantifies that erosion using official Consumer Price Index (CPI) data.

The input data is a month-by-month series of Year-over-Year CPI inflation rates — the headline “inflation number” that central banks and statistics agencies publish. For Indonesia we use the CPI (Indeks Harga Konsumen) reported by Badan Pusat Statistik; for the United States, the headline CPI-U from the Bureau of Labor Statistics. Both cover January 1990 through December 2025.

The formula

Equivalent amount = Original amount × (CPI_to / CPI_from)
Cumulative inflation % = (CPI_to / CPI_from − 1) × 100
Annualized rate = (CPI_to / CPI_from)^(12/months) − 1

We reconstruct the CPI index by chaining Year-over-Year values: starting from CPI(Jan 1990) = 100, we compute CPI(Jan of next year) = CPI(Jan prior) × (1 + YoY(Jan next)). The other months of the anchor year are back-solved from the 1991 YoY series. The result is a complete monthly index spanning 36 years for each country.

Why Indonesia and the US look so different

Between 1997 and 1999, during the Asian Financial Crisis, Indonesian inflation spiked above 77% year-on-year, and the rupiah lost more than 80% of its value against the dollar. Even outside that shock, Indonesian inflation has historically run 3–6 percentage points higher than US inflation. Cumulatively since January 1990, prices in Indonesia have multiplied roughly 18×; in the US, roughly 2.4×. That's why your grandparents' stories about how cheap things used to be sound so much more dramatic in Jakarta than in Chicago.

Common uses

  • Salary negotiation — check whether a raise offer keeps up with inflation. If your 2020 salary hasn't grown faster than cumulative inflation since, you've taken a real-terms pay cut.
  • Historical context — “Grandpa bought his house for Rp 5 million in 1985” — this tool puts that price in today's money for easier intuition.
  • Investment comparison — your investment returned 60% over 10 years, but if cumulative inflation was 50%, your real return was only ~7%.
  • Retirement planning — pair with our FIRE / Retirement calculator to see how inflation eats into a nest egg.
  • Content & research — journalists, bloggers, and researchers use calculators like this to normalize prices across eras for fair comparison.

Technical notes & caveats

  • CPI ≠ your personal inflation. The headline CPI is a basket average. Your actual cost of living may rise faster (if you spend heavily on rent, education, or healthcare) or slower (if you spend on electronics).
  • Hedonic adjustments. Modern CPI methodology adjusts for quality changes — a 2025 car is safer, more fuel-efficient, and more equipped than a 1990 car at the same nominal price. Critics argue this understates true inflation; defenders say it correctly measures constant-utility prices.
  • Indonesian base-year revisions. Indonesia's BPS has revised the CPI base year several times (2002, 2007, 2012, 2018, 2022). Our data uses the reported YoY figures, which are consistent across revisions.
  • For US currency before 1990, try the BLS official calculator. This tool starts at January 1990.

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