Purchasing Power Parity (PPP)

Macroeconomics
Updated Apr 2026 Has calculator

An implied exchange rate based on the ratio of price levels between two countries.

What is PPP?

Purchasing power parity (PPP) is an economic theory that exchange rates should adjust until identical goods cost the same in every country when priced in a common currency. The implied PPP exchange rate is simply the ratio of the local price to the US price for an identical basket of goods. If the actual spot rate differs, the currency is either over- or undervalued relative to PPP. The IMF and World Bank use PPP-adjusted GDP to compare economic output across countries in a way that accounts for differences in price levels rather than just market exchange rates.

Formula

PPP Rate = Local Price ÷ US Price

Worked Example

Worked example — IMF — World Economic Outlook, 2024

2024 — Japan vs United States

Step 1  Price of a representative consumer basket in Japan: ¥130,000
Step 2  Same basket in the United States: $1,000
Step 3  PPP-implied rate = ¥130,000 ÷ $1,000 = ¥130.00 per USD
Step 4  Actual USD/JPY spot rate (2024 avg): ¥153 per USD
Step 5  → JPY is ~15% undervalued vs USD on a PPP basis (spot exceeds PPP rate)

Source: IMF — World Economic Outlook Database 2024 (2024-04-01)

Calculate PPP

Price of the basket/good in the local currency

Price of the same basket/good in US dollars

PPP-Implied Rate (local per USD)

Not investment advice.

How to Interpret PPP

< 0
Invalid — prices must be positive
> 0
Compare to spot rate: below spot = undervalued, above = overvalued

📚 Forex Basics — Complete the path

  1. FX Cross Rate
  2. PPP
  3. Big Mac FX
  4. Interest Rate Parity
  5. Carry Trade Return