Money quietly loses value every year — what costs an amount today will cost more in future, and a sum sitting still buys less. This shows how much you'll need to keep the same buying power, and what a future amount is really worth in today's money. It's the reason long-term plans should be thought of in today's terms. Nothing is sent to a server.
| In… | You'll need | Buying power of that sum today |
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Chasing inflation in your head is hard. The full Glidepath planner does it for you — every figure is shown in today's purchasing power, using your real (after-inflation) return, so "$1.5M at 60" actually means $1.5M of today's money. It adds taxes in 43 countries, pensions, Monte Carlo and your whole life plan — free and private.
Open the full FIRE planner →Inflation is the steady rise in prices, so each unit of money buys a little less over time. The effect is small year to year but huge over decades, because it compounds. At 3% a year, prices roughly double in 24 years — which means money kept under the mattress loses about half its buying power over that span. This is the single biggest reason saving cash isn't enough for the long term: you need returns that at least keep pace with inflation.
Two directions, both exact:
Future amount needed = Amount × (1 + rate)years Today's value of a future sum = Amount ÷ (1 + rate)years
The first tells you how much you'll need later to buy what an amount buys now; the second tells you what a future pile of money is really worth in today's terms. They're the same equation, run forwards or backwards.
Quoting a retirement number in future dollars is misleading — it sounds bigger than it is. So the full Glidepath planner keeps everything in today's purchasing power and grows your investments at the real (after-inflation) return. You never have to mentally deflate a number.
Related: Compound interest · Savings rate · How long will my money last?
Estimates only, not financial advice. Assumes a constant inflation rate; real inflation varies year to year and by what you buy. Your inputs stay in your browser — nothing is sent to a server. · Full planner · All calculators · Compound interest · How it works · Feedback