What this calculator does
Herfindahl-Hirschman Index (HHI) works out market concentration measured from the sum of squared market shares of each firm. Enter your own figures above and the answer updates as you type: nothing is fixed in the code, so the result reflects exactly the numbers you supply.
The formula this calculator evaluates is printed under the tool and explained below, so you can check the working by hand or reuse it in a spreadsheet.
The formula
FormulaHHI = Σ sᵢ², where sᵢ is each firm's market share as a percentage
The inputs explained
| Field | What to enter |
|---|---|
| Market shares, comma-separated (%) | A list of numbers, separated by commas or spaces. |