Inflation Calculator

Quick answer: At 2.5% inflation, $100 today becomes $128.01 in ten years, a rise of 28%. Turned around, $100 in ten years will only buy what $78.12 buys now. Enter any amount, rate and number of years to see both directions.

This inflation calculator shows how the buying power of money changes over time, working out both the future cost of today's prices and the real value of a future sum in today's money. Inflation is the steady rise in the general level of prices, which means a dollar buys a little less each year, and over a decade or two the effect is large enough to reshape budgets, savings goals and retirement plans. You enter an amount, an assumed average annual inflation rate and a number of years, and the calculator compounds the rate across the years to give two views. The first is the future cost: what something priced at your amount today would cost after that many years of inflation. The second is the real value: what a fixed amount of money received in the future would be worth in today's buying power, which shows why cash left under the mattress quietly loses value. The Reserve Bank of New Zealand targets inflation of 1 to 3 percent, averaging around 2 percent, so a long-run assumption of 2 to 3 percent is reasonable, though recent years have at times run higher. This calculator uses an assumed rate you choose rather than official index data, which is ideal for projections; for exact historical figures, see the Reserve Bank and Stats NZ. Enter your figures to see the effect of inflation straight away.

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%
$128.01
future cost of $100 worth of goods
Real value of that future $100$78.12
Total price rise28%

Uses an assumed average annual rate, compounded yearly. For official historical CPI, see the Reserve Bank of New Zealand. Estimate only.

How it works

The calculator compounds the annual rate over the years. The future cost is the amount times one plus the rate, raised to the number of years. The real value of a future amount is the amount divided by that same factor, showing its buying power in today's money.

Worked example

At 2.5 percent inflation, 100 dollars of goods today would cost about 128 dollars in ten years. Looked at the other way, 100 dollars received in ten years would buy only about 78 dollars worth of today's goods.

Who this calculator is for

This calculator is for anyone seeing how prices and the purchasing power of money change over time in New Zealand, for budgeting, planning or comparing past and present values.

What this calculator assumes

  • The amount, time period and inflation rate (or CPI data) you enter.
  • A constant rate over the period unless actual CPI figures are used.
  • Past inflation is not a prediction of future inflation.
  • Results are indicative.

Related calculators

Data sources: the rates and thresholds on this page are maintained against Stats NZ. Figures are checked twice monthly.

Frequently asked questions

How does inflation affect my money?

Inflation raises prices over time, so the same amount of money buys less. At 2.5 percent inflation, something costing 100 dollars now would cost about 128 dollars in ten years.

What inflation rate should I use?

The Reserve Bank of New Zealand aims to keep inflation between 1 and 3 percent, averaging around 2 percent, so a long-run figure of 2 to 3 percent is a reasonable assumption. Recent years have at times been higher.

Is this based on official CPI figures?

No. It uses an assumed average annual rate that you choose, which is ideal for projections. For official historical figures, see the Reserve Bank of New Zealand inflation calculator and Stats NZ.