How to use this calculator
- Enter initial price, final price, initial quantity, final quantity.
- 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
Elasticity = midpoint percentage quantity change / midpoint percentage price change.
Assumptions and limitations
Two observations alone do not identify causation or isolate other demand factors.
Worked example
With initial price = 10, final price = 12, initial quantity = 100, final quantity = 80, signed midpoint elasticity is approximately -1.2222222.
What the result means
The sign shows direction; magnitude above one indicates an elastic response between these observations.
Common questions
How should I interpret signed midpoint elasticity?
The sign shows direction; magnitude above one indicates an elastic response between these observations.
What should I check before using this result?
Two observations alone do not identify causation or isolate other demand factors.
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.