GDP data explained: current US$, constant prices and PPP
When to use GDP in current US dollars, constant prices or PPP, why country rankings change between them, and real 2025 World Bank figures to show it.
Use GDP in current US dollars to compare the size of economies in one year at market exchange rates. Use GDP at constant prices to measure real growth over time. Use GDP at purchasing power parity (PPP) to compare the volume of goods and services economies produce, or average living standards, across countries. Divide any of them by population when you care about the average person rather than the whole economy.
The choice changes the answer. In the World Bank's 2025 figures, China's GDP is $19.50 trillion at market exchange rates and 41.26 trillion international dollars at PPP. The United States is $30.77 trillion in both. So the United States ranks first by one measure and China by the other. India is sixth at market exchange rates and third at PPP.
All figures below come from the World Bank's World Development Indicators (WDI) API, retrieved on 2026-10-08. 2025 is the latest year, available for 186 economies at current US dollars and 185 at PPP. The newest year is the one most likely to be revised.
What are the four GDP measures and their World Bank codes?
| Measure | WDI code | Unit | Answers |
|---|---|---|---|
| GDP, current US$ | NY.GDP.MKTP.CD |
US dollars at each year's exchange rate | How big is this economy in dollars this year? |
| GDP, constant 2015 US$ | NY.GDP.MKTP.KD |
US dollars at 2015 prices | How much did real output grow? |
| GDP, PPP, current international $ | NY.GDP.MKTP.PP.CD |
International dollars | How much does this economy produce, valued at common prices? |
| GDP per capita (current US$ or PPP) | NY.GDP.PCAP.CD, NY.GDP.PCAP.PP.CD |
Per person | What is output per resident? |
The World Bank also publishes real growth directly as NY.GDP.MKTP.KD.ZG (annual %), calculated as the year-on-year change in the constant-price series.
Current US dollars
Each country measures GDP in its own currency. To compare, the World Bank converts at the year's average market exchange rate. The result is the right measure for anything that is bought or paid at market exchange rates: imports, foreign debt, a country's weight in world trade, or its share of a dollar-denominated budget. Its weakness is that exchange rates move a lot from year to year, so the dollar value of an economy can rise or fall without any change in what it produces.
Constant prices
Current-price GDP rises when prices rise. Constant-price GDP removes that effect by valuing every year's output at the prices of a reference year, 2015 for the WDI US-dollar series. Growth in constant-price GDP is real growth. This is the series to use for any question about change over time within a country.
Purchasing power parity
A haircut, a bus ride or a bag of rice costs far less in New Delhi than in New York when converted at market exchange rates. Market rates therefore understate how much is actually produced in lower-price countries. PPP conversion factors, produced by the International Comparison Program (ICP), compare the prices of the same basket of goods and services across countries and convert GDP into international dollars. An international dollar is defined to buy the same amount in each country as a US dollar buys in the United States, which is why US GDP is identical in both series.
According to the indicator metadata, the WDI PPP series retrieved for this article are based on the ICP 2021 benchmark, published on May 30, 2024, and the constant-price PPP series is expressed in constant 2021 international dollars (NY.GDP.MKTP.PP.KD). Years other than the benchmark year are extrapolated from it.
Why do GDP rankings differ between current US$ and PPP?
| Economy | GDP, current US$ (trillion) | Rank | GDP, PPP (trillion int. $) | Rank | PPP ÷ current US$ |
|---|---|---|---|---|---|
| United States | 30.77 | 1 | 30.77 | 2 | 1.00 |
| China | 19.50 | 2 | 41.26 | 1 | 2.12 |
| Germany | 5.05 | 3 | 6.30 | 6 | 1.25 |
| Japan | 4.44 | 4 | 6.84 | 5 | 1.54 |
| United Kingdom | 4.00 | 5 | 4.49 | 9 | 1.12 |
| India | 3.96 | 6 | 17.20 | 3 | 4.35 |
| France | 3.37 | 7 | 4.40 | 10 | 1.31 |
| Russia | 2.56 | 8 | 7.24 | 4 | 2.82 |
| Brazil | 2.28 | 11 | 4.99 | 8 | 2.19 |
| Indonesia | 1.45 | 17 | 5.05 | 7 | 3.49 |
| World | 118.35 | 211.17 | 1.78 |
Ranks are among all economies with a 2025 value in each series, excluding the World Bank's regional and income aggregates.
The last column is the key. It shows how many times larger an economy looks at PPP than at market rates, and it is high where prices are low relative to the exchange rate. India's GDP is 4.35 times larger at PPP; the United Kingdom's only 1.12 times. By share of the world total, the United States is 26.0% of world GDP at market rates and 14.6% at PPP. China is 16.5% and 19.5%. India is 3.3% and 8.1%.
The arithmetic behind the conversion
You can reproduce China's PPP figure from three WDI series: GDP in current US dollars, the official exchange rate (PA.NUS.FCRF, yuan per US dollar, 2025 average: 7.190) and the PPP conversion factor (PA.NUS.PPP, yuan per international dollar: 3.398).
=GDP_usd * exchange_rate / ppp_factor
19.50 × 7.190 / 3.398 = 41.26 trillion international dollars, the published value. The ratio of the PPP factor to the exchange rate, 3.398 / 7.190 = 0.473, is an implied price level: on this measure, prices in China are about 47% of US prices when converted at market exchange rates. The same calculation gives 0.230 for India, 0.649 for Japan and 0.802 for Germany.
Per person
| Economy | GDP per capita, current US$ | GDP per capita, PPP (int. $) |
|---|---|---|
| United States | 90,027 | 90,027 |
| Germany | 60,496 | 75,407 |
| United Kingdom | 57,602 | 64,606 |
| Japan | 35,951 | 55,422 |
| China | 13,862 | 29,333 |
| India | 2,702 | 11,748 |
China's economy is larger than the United States' at PPP, but its output per person at PPP is about a third of the US level (29,333 / 90,027 = 0.33). Total size and average living standards are different questions.
How does growth in current US$ differ from real growth?
Percentage change is =new/old-1 (see how to calculate percentage change). Applied to 2019 and 2025:
| Economy | Current US$, 2019 → 2025 (trillion) | Change | Constant 2015 US$, 2019 → 2025 (trillion) | Real change |
|---|---|---|---|---|
| United States | 21.54 → 30.77 | +42.8% | 20.16 → 23.22 | +15.2% |
| Germany | 3.96 → 5.05 | +27.6% | 3.68 → 3.69 | +0.3% |
| Japan | 5.25 → 4.44 | −15.5% | 4.66 → 4.76 | +2.1% |
In the United States, most of the 42.8% rise in current dollars was inflation; real output grew 15.2%. Germany's dollar GDP rose 27.6% while its real output barely moved. Japan's dollar GDP fell 15.5% even though real output grew 2.1%. The yen weakened from an average of 109.0 per dollar in 2019 to 149.7 in 2025. Converting back with those exchange rates, Japan's GDP in yen rose from about 572 trillion to 664 trillion yen, a nominal increase of 16.1%.
The same thing happens over a single year. Germany's real growth in 2025 was 0.24%, but its GDP in current US dollars rose 7.80%, largely because the euro was stronger against the dollar.
What mistakes do people make with GDP data?
- Reading growth from current US dollars. As the Japan example shows, the sign can even be wrong. Use the constant-price series or
NY.GDP.MKTP.KD.ZG. - Using PPP for things paid at market rates. A country's ability to import oil, service dollar debt or pay for foreign equipment depends on market exchange rates. PPP is for comparing volumes and living standards.
- Comparing levels across constant-price bases. Constant 2015 US dollars and constant 2021 international dollars are different units. Never put them in the same column.
- Mixing PPP vintages. When the World Bank adopts a new ICP benchmark, PPP-based values are revised for past years too. A table assembled from a download made before the ICP 2021 update and one made after it can mix two sets of prices.
- Mixing sources. The World Bank, the IMF's World Economic Outlook and national statistics offices publish different figures for the same country and year because of revision timing, exchange rate choices and estimates for missing data. Pick one source for a comparison and cite it with the retrieval date.
- Confusing GDP with GNI. The World Bank's income groups (low, lower-middle, upper-middle, high income) are based on gross national income (GNI) per capita, converted with the Atlas method, not on GDP per capita.
- Averaging per-capita values. The average of China's and India's GDP per capita is not the GDP per capita of the two together. Sum the GDP, sum the population, then divide.
Which GDP series should you use for a given question?
| Question | Series |
|---|---|
| Which economies are biggest this year, in dollars? | GDP, current US$ |
| How fast did this economy grow? | GDP, constant prices, or annual growth % |
| Which economies produce the most goods and services? | GDP, PPP |
| How do average living standards compare across countries? | GDP per capita, PPP |
| What share of world trade or dollar debt can a country support? | GDP, current US$ |
| How has output per person changed over time? | GDP per capita, constant prices |
How do you start working with GDP data in a spreadsheet?
- Download the series you need for one consistent retrieval date, and record that date and the indicator codes in a notes column.
- Keep each series in its own table with one row per country and one column per year, and never mix units in a column.
- Calculate growth from constant-price data with
=C2/B2-1, or use the World Bank's published growth rate. - For shares of the world, divide by the World Bank's world aggregate rather than by your own sum of countries, which will miss economies without data.
- Join population or area on ISO3 codes from a reference table such as world countries geography.
The GDP by country workbook has current-US-dollar GDP, GDP per capita and real growth by year with the World Bank's aggregates on a separate tab. For a short answer on the PPP question alone, see nominal GDP vs GDP PPP, and for credit lines, how to cite World Bank data.