Inflation Calculator — What Your Money Is Worth Over Time

Inflation & Purchasing Power Calculator

See what money is really worth over time. Project how much value it loses to future inflation with an up and down band, or check how far prices have risen using real historical data for the UK, US, India, the euro area and the world.

What to work out

Direction

Inflation history

Amount

Years ahead

yrs

Inflation / yr

Historical data is bundled so the page works offline. Updating makes one request to the World Bank for newer figures — nothing else is sent.

Value in the future

Worth in 10 years 0 in today's money

Purchasing power kept—

Value lost to inflation—

If inflation runs low → high—

Same basket will cost—

Purchasing power over time

Central High inflation

Historical figures use annual-average consumer price indices — ONS for the UK, the US Bureau of Labor Statistics, Eurostat for the euro area, India's Ministry of Statistics, and a World Bank world aggregate — bundled into the page so nothing is fetched and nothing is tracked. Future values are projections at the rate you set, not predictions. Currency selection relabels; it never converts between currencies.

How the maths works

The formula behind this calculator, with a worked example built from your own inputs.

Inflation & purchasing powerInflation

Future real value = A ⁄ (1 + r)ⁿ · Past equivalent = A × (I_now ⁄ I_year)

A = the amount · r = yearly inflation · n = years · I = the consumer price index in a given year.
Money has no fixed value — only what it buys. Looking forward, dividing a sum by (1 + r)ⁿ shows what it will still be worth once prices have risen; the up/down band runs the same maths 1.5 points either side of your rate, because the future rate is unknown. Looking back, the ratio of today's price index to an earlier year's says how much more money is now needed to match what an amount once bought. Historical indices are annual averages published by national statistics offices (ONS, US BLS, Eurostat, India's MoSPI) plus a World Bank world aggregate, and are bundled into the page.

Worked example: £1,000 losing value at 2.5% a year is worth about £781 in today's money after 10 years — and to buy the same basket you would then need about £1,280.

About the currency selectorCurrency

Changing the currency relabels the figures — it does not convert them. There are no exchange rates involved, and nothing is fetched from the internet.

If you enter 280,000 and switch from pounds to dollars, the tool reads it as 280,000 dollars, not as a converted amount. The maths is identical in every currency because percentages, ratios and time don't care about the unit — a 25-year loan at 4.8% has the same payment-to-principal relationship whether it's in yen or rand.

What does change is formatting, which follows each region's own conventions: where the symbol sits (€ goes after the number in German), which separators are used (Switzerland uses apostrophes, South Africa uses spaces), how digits are grouped (India groups in lakhs — 1,71,120 rather than 171,120), and whether decimals exist at all (yen and won have no minor unit).

So pick the currency you're actually working in and enter local amounts. Don't enter pounds and switch to dollars expecting a conversion.

Assumptions & what these formulas ignoreImportant

Interest compounds monthly on the outstanding balance — standard for UK repayment mortgages, though some lenders calculate daily, giving slightly different totals.

Rates are assumed fixed for the whole term. In reality a fixed period ends and you revert or remortgage, so long-term totals are illustrative.

Not included anywhere: arrangement and broker fees, stamp duty, early repayment charges, void periods, maintenance, letting agent fees, income or capital gains tax, and inflation. Figures are in today's money.

Overpayment caps: many fixed deals limit penalty-free overpayments to around 10% of the balance a year.

Investment returns assume future variability resembles the past — which markets regularly break. Depreciation curves are typical patterns, not valuations; real resale depends on mileage, condition, spec and demand.

These tools are for estimating and comparing options. They aren't financial advice, and for a decision that matters it's worth speaking to a qualified adviser or broker.

Frequently asked questions

Direct answers about this calculator.

How do you work out what money will be worth in the future?

Divide the amount by (1 + inflation rate) raised to the number of years: real value = A / (1 + r)^n. At 2.5% inflation, 1,000 is worth about 781 in today's money after 10 years, because prices rise roughly 28% over the same period. No one knows future inflation exactly, so it is more honest to show a band - a lower rate leaves more value, a higher rate leaves less - than a single figure. The same arithmetic in reverse gives the future sticker price: what you would need to spend later to buy what the amount buys today.

What is money from the past worth today?

Multiply the old amount by the ratio of today's consumer price index to the index in that year: equivalent = amount x (index now / index then). Because prices generally rose over the period, the same goods cost more now, so you need more money to match the old purchasing power. This tool uses real annual-average price indices from national statistics offices, so the past figures are historical record rather than estimates - only the forward projection involves an assumed rate.

About these calculators

How the numbers are produced, what they are not, and where to get regulated advice.

How the numbers are produced

Every figure comes from a published formula shown openly in the How the maths works section, alongside a worked example built from your own inputs. Nothing is estimated, weighted or adjusted behind the scenes.

The calculations run entirely in your browser. Nothing is stored, no accounts, no tracking, no adverts, and no affiliate links to mortgage or insurance products. Nobody pays to appear here, so there is no incentive to nudge a result in any direction. The one time anything leaves your device is if you click Update to latest figures on the inflation tab — that makes a single request to the World Bank's open data API for newer price indices, and sends nothing about you. Every other figure, including the bundled inflation history, is already in the page.

Default rates and depreciation curves are typical illustrative figures, not live market data. The tools do not fetch interest rates, house prices, exchange rates or resale values from anywhere.

Limitations — read before relying on this

These are estimating tools for comparing options, not a substitute for professional advice. In particular:

· Figures exclude fees, stamp duty, early repayment charges, tax, void periods, maintenance and inflation.
· Rates are assumed fixed for the whole term; in reality fixed periods end and you revert or remortgage.
· Investment simulations assume future variability resembles the past — which markets regularly break. They show modelled uncertainty, not a forecast.
· Depreciation curves are typical patterns, not valuations. Real resale depends on mileage, condition, spec and demand.
· Changing currency relabels figures; it does not convert them.

For a decision that matters, speak to a qualified mortgage broker, accountant or FCA-regulated financial adviser. Nothing here is financial advice.

Sources & further reading

For impartial, regulated guidance in the UK:
· MoneyHelper — the government-backed free money guidance service
· MoneySavingExpert — mortgage guides and comparison tools
· Bank of England — current Bank Rate
· GOV.UK — Stamp Duty Land Tax
· FCA — checking an adviser is regulated

The amortisation, yield and depreciation formulas used here are standard published finance formulas, not proprietary methods — you are encouraged to check them against any other source.