How to use this calculator
- Enter market shares in percent, summing to 100.
- Choose a display currency, then select Calculate. Results also update after a brief pause while you edit.
- Read the result with the assumptions below. Export details or save a second scenario to compare your choices.
Formula and method
Assumptions and limitations
Shares must exhaust the defined market; market definition is a substantive judgment. No legal merger threshold or regulatory conclusion is inferred.
Worked example
With market shares in percent, summing to 100 = 50,30,20, example hhi is approximately 3800.
What the result means
Measure concentration across the firms or portfolio segments you supply.
Common questions
How should I interpret example hhi?
Measure concentration across the firms or portfolio segments you supply.
What should I check before using this result?
Shares must exhaust the defined market; market definition is a substantive judgment. No legal merger threshold or regulatory conclusion is inferred.
Methodology and transparency
Calculation specification reviewed on 2026-10-14. Mathematical implementation is tested against independent reference fixtures. This does not imply review by a licensed financial professional. Read the testing and precision policy.