How to use this calculator
- Enter option type, underlying price at expiry, long option strike, short option strike, premium paid per unit, premium received per unit, underlying units per leg.
- 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
Equal quantities, expiry-only, no fees, assignment, margin, early exercise or live pricing.
Worked example
At expiry price 120, a long call struck at 100 is worth 20 and a short call struck at 110 costs 10 to settle. Paying 12 and receiving 5 in premiums gives net profit (20 − 10 − 12 + 5) × 100 = 300 for 100 underlying units.
What the result means
Model expiry profit/loss for one long and one short option of the same type and expiry.
Common questions
How is the calculation performed?
Profit=[long intrinsic−short intrinsic−long premium+short premium]×units.
What does the model leave out?
Equal quantities, expiry-only, no fees, assignment, margin, early exercise or live pricing.
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.