People ask about inflation in two opposite directions. Someone planning a purchase wants to know what a thing will cost in five years. Someone holding savings wants to know what their money will be worth by then. Both answers come from the same compound factor — one multiplies by it, the other divides — and showing only one of them is how a page leaves half its readers doing the arithmetic backwards in their heads.

Using it in three steps

1. 1 Type the amount you care about — a price today, or savings you are holding.
2. 2 Put in a yearly rate. Use your country's recent figure, or try a few to see how sensitive the answer is.
3. 3 Read both boxes. The left one answers "what will it cost", the right one "what will my money buy".

Why small rates matter over long periods

Inflation compounds, so the effect is not the rate times the years. At 3% a year, prices do not rise 30% in a decade — they rise 34%, and over twenty-five years they more than double. The difference between 2% and 4% looks trivial on a single year and is enormous on a working life: over forty years, one multiplies prices by 2.2 and the other by 4.8.

Why no official index is built in

A consumer price index is a national series that changes every month and differs wildly between countries — this site is read in fourteen languages across dozens of them. Embedding one would mean fourteen maintenance obligations and an answer that quietly rots between updates. A rate you choose yourself stays correct forever, and it also lets you ask the question that official data cannot: what if inflation runs at 8% instead of 3%?