Estimate how inflation changes the value of money over time. Enter a starting amount, start and end years, and an average annual inflation rate — or open advanced options to use historical CPI data for the United States, Philippines, United Kingdom, Japan, or the Eurozone, or upload your own CPI dataset as a CSV. See future value, purchasing power lost, total inflation, and a year-by-year chart.

Disclaimer

This Inflation Calculator is for general planning and educational use. Results use a constant average annual inflation rate you enter, bundled approximate historical CPI rates by country, or a CPI dataset you upload yourself. Bundled CPI values are rounded estimates and may differ from official national statistics. When your selected years extend past the end of a CPI dataset, the remaining years use the annual rate you entered. Currency selection only changes how amounts are formatted — it does not convert between currencies.

How to Use a Custom CPI Dataset

Instead of the bundled country data, you can upload your own Consumer Price Index (CPI) dataset — for example, official figures for a country or region we do not include, or the latest published numbers. The file is read entirely in your browser for the current session only: nothing is uploaded to a server, and the dataset is cleared when you refresh or close the tab.

Step-by-step

• Tick Show advanced options under the calculator inputs.
• For Inflation Rate Source, choose Use historical CPI dataset.
• In the Country / Dataset dropdown, select Custom (uploaded dataset).
• Choose the CSV value type that matches your file — either Annual inflation rate (%) or Raw CPI index.
• Click Upload CPI CSV and pick your file. A confirmation shows the row count and the years covered once it parses successfully.
• Set your Starting Amount and years, then click Calculate. For any years after your dataset ends, the calculator automatically uses the annual rate you enter in the rate field.

Required file format

Save a plain .csv with a period column and a value column (e.g. period,value or IMF's TIME_PERIOD,OBS_VALUE). Extra metadata columns such as a country name are detected and ignored automatically. A header row is optional. Periods can be annual, quarterly, or monthly:

• Annual — 2020,3.2
• Quarterly — 2020-Q1,112.4 (also accepts 2020Q1)
• Monthly — 2020-M01,111.8 (also accepts 2020M1 or 2020-01)

Quarterly and monthly rows are averaged into a single value per calendar year. Years that are missing periods (for example the current year with only one quarter so far) are skipped, and the remaining years must be contiguous with no gaps. If you selected Raw CPI index, yearly rates are derived automatically with (index_year / index_previous_year − 1) × 100.

Example CSV (annual rate percent):

year,value
2018,2.4
2019,1.8
2020,1.2
2021,4.7

Where to download CPI data

These sources publish official CPI series (as an index) or inflation rates that you can export to CSV. Extra descriptive columns are ignored automatically — what matters is that the file covers a single country and a single indicator series.

• IMF Data — data.imf.org (Consumer Price Index). Best results: before downloading, filter to one country, one indicator (e.g. CPI index or inflation rate), and preferably annual frequency. If you upload a bulk export that mixes several series, the calculator keeps only the first series it finds and shows a warning — always check that the year range in the warning matches the data you intended.
• World Bank — Inflation, consumer prices (annual %).
• OECD Data Explorer — data-explorer.oecd.org (Prices > Consumer prices).
• FRED (US Federal Reserve) — fred.stlouisfed.org (search "CPI", then Download > CSV).
• National statistics offices — e.g. the U.S. Bureau of Labor Statistics (bls.gov/cpi) or the Philippine Statistics Authority (psa.gov.ph).

Tip: most portals export extra descriptive columns (country name, unit, notes). The calculator detects the period and value columns automatically, so trimming is optional — but a clean two-column file is the easiest to verify at a glance.

Downloading a working file from IMF Data (step by step)

A raw bulk IMF export mixes many countries, indicators, and frequencies into a single file — the same year then appears thousands of times. The calculator recovers by keeping only the first series and warning you, but the safest approach is to narrow the download first:

1. Open data.imf.org and go to the Consumer Price Index (CPI) dataset.
2. Filter to one country (for example, Philippines or United States).
3. Filter to one indicator — either a CPI index or an inflation rate.
4. Set the frequency to Annual (annual data works best; quarterly and monthly are also accepted and will be averaged into years).
5. Export or download the series as CSV.
6. Extra columns such as COUNTRY are fine — the calculator finds the TIME_PERIOD and OBS_VALUE columns automatically.
7. Back in this calculator, select Raw CPI index or Annual inflation rate (%) to match your values, then upload the file.

A valid file for a single series looks like this:

TIME_PERIOD,OBS_VALUE
2018,100.0
2019,102.1
2020,103.4
2021,108.2

How This Inflation Calculator Works

Enter a starting amount, start year, and end year. Use a custom average annual inflation rate, or open Advanced options to apply a historical CPI dataset for the United States, Philippines, United Kingdom, Japan, or the Eurozone — or upload your own CPI CSV. The tool uses available CPI rates through the dataset's final year, then applies your custom annual rate to later years. It estimates future value, purchasing power lost, and total inflation, then charts both the inflation-adjusted value and purchasing power over time.

Note on year counting: the start year is the baseline, and inflation compounds for each full year after it. In CPI mode this means the rates for start year + 1 through the end year are applied — for example, 2020 to 2023 compounds the 2021, 2022, and 2023 rates.

Formulas

• Future Value — Future Value = Present Value × (1 + Inflation Rate)^Years
• Purchasing Power — Purchasing Power = Present Value / (1 + Inflation Rate)^Years
• CPI mode — compounds each year's actual rate: Future Value = Present Value × Π(1 + r_year)
• Effective average rate (CPI mode) — (Future Value / Present Value)^(1 / Years) − 1

Worked Example

Amount: $1,000 · Inflation: 3% · Years: 10

Future Value = 1000 × (1.03)^10 = $1,343.92

Purchasing Power = 1000 / (1.03)^10 ≈ $744.09

Reading the Results

• Inflation Rate — average annual rate used (custom input, or effective rate implied by the CPI path).
• Future Value — what the same purchasing power would cost at the end year after inflation. This is not investment growth; it shows how much more money you would need to buy the same things.
• Purchasing Power Lost — how much buying power the original amount loses over the period.
• Total Inflation — the cumulative percent rise from present value to future value over the whole period (also called the percentage increase; they are the same figure).

Frequently Asked Questions

What is an inflation calculator?
An inflation calculator estimates how the purchasing power of money changes over time due to inflation. It helps compare the value of money between different years.

How does an inflation calculator work?
It compounds an inflation rate over each year of the selected period. The result shows how much money you would need at the end year to match the starting amount's buying power (future value), and how much of the original buying power remains (purchasing power).

What is inflation?
Inflation is the gradual increase in the prices of goods and services over time, causing the purchasing power of money to decrease.

Why does inflation reduce purchasing power?
As prices rise, the same amount of money buys fewer goods and services than it did in the past.

Is this inflation calculator free to use?
Yes. Our inflation calculator is completely free and can be used as many times as you like.

What is the Consumer Price Index (CPI)?
The Consumer Price Index (CPI) measures the average change in prices paid by consumers for a basket of goods and services over time. It is one of the most common measures of inflation.

Why is CPI used to measure inflation?
CPI tracks changes in everyday living costs and provides a standardized way to measure inflation.

Where does CPI data come from?
CPI data is typically published by government statistical agencies or international organizations such as the World Bank, IMF, or national statistics offices.