Okun's law calculator
See how a change in the unemployment rate lines up with real GDP growth relative to trend, or run the arithmetic the other way. You choose the Okun coefficient. Every step stays visible. This is a classroom rule of thumb, an empirical regularity, not a law of nature, and not a forecast. The arithmetic runs entirely in your browser.
A common textbook starting point is about 2. A rise in unemployment of 1 percentage point then lines up with real GDP growth about 2 percentage points below trend. Okun's 1962 illustration was closer to 3. Later US samples often sit nearer 2. This number is an assumption you type, not a live official estimate.
Direction
From an unemployment change, the growth gap equals minus the coefficient times that change. From a GDP growth gap, the unemployment change equals minus the gap divided by the coefficient.
Positive means the unemployment rate rose. Negative means it fell. Example: 1 means the rate moved from 4 percent to 5 percent. Type the change yourself. This is not a live BLS or ONS print.
Actual real GDP growth minus trend or potential growth. Positive means growth above trend. Example: actual growth of 4 percent and trend growth of 2 percent is a gap of 2. Look up BEA or ONS growth, choose a trend, then type the difference.
Arithmetic
In words
Reciprocal slope
Defaults use a coefficient of 2 and an unemployment rise of 1 percentage point. The implied GDP growth gap is minus 2 percentage points, so growth sits 2 points below trend. Switch to the growth gap direction and enter 2. The implied unemployment change is minus 1 percentage point, so the rate falls by 1 point. Those figures are classroom arithmetic. They are not a claim about current unemployment or GDP.
Not investment advice and not policy advice. Okun's law is an empirical regularity, not a law of nature. Coefficients vary by country and by period. The mapping also misses hours, productivity, and people entering or leaving the labour force. Nothing here recommends buying, selling, or holding any security, or choosing a tax, spending, or interest rate. The calculator does not fetch live data.
The classroom formula
This page uses a simple difference form taught alongside Okun's 1962 discussion of potential output:
GDP growth gap ≈ minus Okun coefficient × change in unemployment
Change in unemployment ≈ minus GDP growth gap ÷ Okun coefficient
The GDP growth gap means actual real GDP growth minus trend or potential growth, in percentage points. The unemployment input is a change in the unemployment rate, also in percentage points. It is not the level of the rate. A coefficient of 2 is a familiar modern textbook starting point. It is the inverse of a slope near one half. Okun's 1962 rule of thumb was nearer a coefficient of 3, so a 1 point unemployment change lined up with about a 3 percent output gap. Research such as Ball, Leigh, and Loungani finds US slopes often nearer 0.4 or 0.5, which is a coefficient near 2 to 2.5, and finds that the number differs across countries. Say which coefficient you used.
For the ideas and the loose spots, read Okun's law explained. For the level version of slack, read the output gap. For a benchmark unemployment rate, which is a different question from a cyclical change, read the natural rate of unemployment.
Where to find the inputs
Type your own numbers. This page does not download official series. For a US sketch, look up the unemployment rate at BLS or on FRED (UNRATE) and real GDP at BEA or FRED (GDPC1). For a UK sketch, look up Labour Force Survey unemployment and real GDP at ONS. Then choose a trend or potential growth assumption and subtract it from actual growth yourself. Broader context sits on the unemployment pillar and the GDP pillar.
UK and US framing
Do not paste a US coefficient onto UK data and call the result a fact. Labour market institutions, hours adjustment, job support schemes, and survey definitions differ. A quarterly US growth rate that is annualised is not the same unit as a UK quarter on quarter rate. Match the units before you type. Use primary releases from BLS, BEA, and ONS.
Sources
- Arthur M. Okun, “Potential GNP: Its Measurement and Significance,” Cowles Foundation Paper 190 (1962)
- FRASER, St. Louis Fed: Arthur M. Okun, “Full Employment GNP: Its Measure and Significance,” American Statistical Association meetings, 8 September 1962
- Laurence Ball, Daniel Leigh, and Prakash Loungani, “Okun's Law: Fit at 50?” IMF Working Paper 13/10 (2013)
- NBER Working Paper 18668, Ball, Leigh, and Loungani, “Okun's Law: Fit at Fifty?”
- BLS, Current Population Survey
- FRED, Civilian unemployment rate (UNRATE)
- BEA, Gross Domestic Product
- FRED, Real Gross Domestic Product (GDPC1)
- ONS, Employment and labour market
- ONS, Gross Domestic Product (GDP)
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