Calculator for Inflation

Formula

Value for today = past amount × (1 + i)^t, where i na average annual inflation rate and t na number of years between two years. Reverse direction — wetin today money worth in past year — divide instead: past value = today amount ÷ (1 + i)^t. Both directions dey use the same growth factor (1 + i)^t.

Example wey show the calculation

Assume yearly inflation rate of 3% from 2000 to 2026, wey cover 26 years. Di growth factor na (1.03)^26 ≈ 2.1566: purchase of $100 for 2000 go cost about $215.66 for 2026. For di reverse, $100 for 2026 get purchasing power of about $46.37 for 2000. Dis na constant-rate illustration, no be official historical price index.

Where e fit work and limits

This page dey use one constant inflation rate wey you assume; e no fetch CPI data. Compound yearly rate fit reproduce change between two index endpoints, but e no fit describe the yearly path between dem. For historical work, use one consistent published CPI series, country and comparison period. The result dey compare general purchasing power, no be the price of one particular item.

U.S. Bureau of Labor Statistics: percentage changes for CPI

Version of di formula: 23622093c909 · Example don get check: 2026-10-31

Questions wey people dey ask often

Why 3% for 26 years dey make prices pass double?

Na compounding. Each year increase dey apply on price level wey don already rise, so the growth dey gather speed: 1.03²⁶ = 2.1566. At 2%, the factor for 26 years na 1.67; at 5%, na 3.56. Small difference for rate fit grow into big difference over time.

The average rate na the same as actual CPI?

We no load data here. To match two published CPI endpoints over t years, enter 100 × ((ending index ÷ starting index)^(1/t) − 1) as yearly rate. If you just average yearly percentage changes with arithmetic mean, you usually no go get the same compounded result. Use matching months or consistent annual-average indexes; those comparisons fit differ.

Wetin "worth $46.37 in 2000 dollars" mean?

E mean say $100 today buy roughly wetin $46.37 buy for 2000. E no mean say anybody hold $46.37 — na same purchasing power expressed for older year prices.

How this one differ from present value calculator?

The maths na the same; both dey use (1 + r)^t — but the rate no mean the same thing. Present value dey discount with return or cost of capital; inflation adjustment dey change the scale with price levels. Na the same formula, but different questions.

Inflation fit be negative?

Yes, na deflation. Negative rate go reduce the growth factor below 1, so the past amount go equal a smaller amount for today money. Enter negative rate to model a period of falling prices.

Why old salaries dey sound so small?

Because of exactly this factor. $30,000 salary for 2000 equal about $64,700 in 2026 dollars at 3% average inflation (30,000 × 2.1566). Comparing nominal amounts across decades without adjusting mislead for both directions.

Other tools wey relate to dis

• Calculator for compound interest — the same compounding maths for savings
• Calculator for savings target — monthly savings wey you need to reach a future target
• Calculator for retirement savings — planning over many years where inflation matter plenty