Okun's Law Calculator

Estimate how a gap between actual and potential GDP growth translates into a change in the unemployment rate, using the standard Okun's Law difference formula.

Quick Facts

Formula
Δu = (g* − g) / c
g is actual real GDP growth, g* is potential (trend) growth, and c is Okun's coefficient.
Origin
Arthur Okun, 1962
Based on postwar U.S. data, Okun found roughly a 2:1 to 3:1 relationship between output gaps and unemployment rate changes.
Typical coefficient
1.5 – 3.0
A value of 2 is the most commonly cited textbook estimate for the modern U.S. economy; it varies by country and period.

Your Results

Calculated
Output growth gap
-
Actual GDP growth minus potential growth
Predicted change in unemployment
-
Δu = (potential − actual growth) / coefficient
Projected unemployment rate
-
Current rate plus predicted change
Labor market signal
-
Direction and size of the projected shift

Ready

Enter actual growth, potential growth, Okun's coefficient, and the current unemployment rate, then press Calculate.

What this calculator does

This tool applies Okun's Law, a well-known empirical relationship in macroeconomics between real GDP growth and the unemployment rate. Enter the actual real GDP growth rate, the economy's potential (trend) growth rate, Okun's coefficient, and the current unemployment rate, and the calculator estimates how much the unemployment rate should move and what it would land at.

The formula

The calculator uses the standard "difference" form of Okun's Law:

Δu = (g* − g) / c

where g is the actual real GDP growth rate, g* is the potential (trend) GDP growth rate, c is Okun's coefficient, and Δu is the resulting change in the unemployment rate in percentage points. The projected unemployment rate is simply the current rate plus Δu. When actual growth matches potential growth, the growth gap is zero and the model predicts no change in unemployment; when actual growth falls short of potential, unemployment is predicted to rise, and when it exceeds potential, unemployment is predicted to fall.

Worked example

Suppose actual real GDP growth is 2.0%, potential growth is 3.0%, Okun's coefficient is 2.0, and the current unemployment rate is 5.0%. The growth gap is 2.0% − 3.0% = −1.0 percentage point. Dividing by the coefficient gives Δu = (3.0 − 2.0) / 2.0 = 0.5 percentage points, so the model predicts unemployment rises from 5.0% to about 5.5%.

Where the coefficient comes from

Economist Arthur Okun first documented this relationship in 1962 using postwar U.S. data, originally estimating a ratio near 3-to-1 between the output gap and the unemployment gap. Later research using more recent U.S. data typically finds a coefficient closer to 2, meaning a 2-percentage-point shortfall in growth relative to potential is associated with roughly a 1-percentage-point rise in unemployment. Because the estimated coefficient depends on the time period, country, and data used, most textbooks present it as a "rule of thumb" — a useful approximation rather than a precise, unchanging law.

Limits of the model

  • It is empirical, not structural. Okun's Law describes a historical statistical correlation, not a causal mechanism with guaranteed stability over time.
  • It ignores labor force participation. The unemployment rate can also move because people enter or leave the labor force, independent of GDP growth.
  • Potential growth is itself an estimate. Economists disagree on the exact trend growth rate at any point in time, and it changes as demographics and productivity evolve.
  • It is a directional guide. Use the output to understand the general relationship between a growth gap and labor market conditions, not as a precise unemployment forecast.

Frequently Asked Questions

What is the formula for Okun's Law?
The calculator uses the difference form of Okun's Law: change in unemployment rate = (potential GDP growth − actual GDP growth) / Okun's coefficient, or Δu = (g* − g) / c. A textbook coefficient of c = 2 means every 2 percentage points that actual growth falls short of potential growth is associated with about a 1 percentage point rise in unemployment.
What is a typical value for Okun's coefficient?
Arthur Okun's original 1962 estimate for the United States was close to 3, but most modern studies put the coefficient closer to 2. Values commonly cited in textbooks and research range from about 1.5 to 3, and the relationship can differ by country and time period, so it should be treated as a rule of thumb rather than a precise law.
Why can the projected unemployment rate be negative or unrealistic?
Okun's Law is a statistical rule of thumb estimated from historical data, not a hard constraint. If the inputs describe an unusually large growth gap, the arithmetic can produce a projected unemployment rate that is very low or even negative — a signal that the model is being pushed outside the range where the historical relationship reliably holds, not a literal forecast.
Does this calculator predict the future unemployment rate exactly?
No. Okun's Law is an empirical approximation, not an exact economic identity. It ignores factors such as labor force participation changes, productivity shocks, and policy responses. Use the output as a directional estimate of how a given growth gap tends to relate to unemployment, not as a precise forecast.

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