Inflation calculator

How to use this page

1. Replace the sample numbers with your own. Nothing is sent to a server.
2. Read the result. It changes as you type.
3. Open the formula if you want to recompute the result by hand.
4. Copy the result if you want to keep it. The numbers you type stay in this browser and are not added to the address.

Formula

Future cost = amount × (1 + rate ÷ 100)^years. Today's value of a future amount = amount ÷ (1 + rate ÷ 100)^years. At 0% the amount does not move. At 3% a year, an amount a bit over doubles in 24 years, because 1.03^24 is about 2.03.

Two directions

Future cost answers: if this grocery bill, rent, or tuition follows the rate I type, what is the sticker later? Today's value answers: a sum I expect to receive later is worth how much spending power now, at that same rate?

The difference is the gap between the two stickers. It is not interest you earn. Inflation is a change in prices, not a payment into your account.

A constant rate is a stress test

Real inflation arrives in bursts and the basket that official statistics use may not match your rent, childcare, or medical bills. Type the rate that describes the cost you care about. Run the page again one point higher.

Deflation is allowed down to −10% so you can see the arithmetic. A negative rate is not a prediction that prices will fall.

Easy mistakes

• Subtracting inflation from an investment return in your head and also using this page on the already-reduced amount.
• Treating the sample rate as this year's official figure. Replace it.
• Using a future cost as the balance you must save without also planning investment growth. Pair it with the savings goal if you will invest the deposits.