What open interest measures
Open interest counts outstanding contracts, with a buyer and seller on opposite sides. Large OI identifies concentration, not trader identity or directional conviction. A put position can be a hedge or part of a spread; a call can be sold as well as bought.
How to use the worksheet
- Replace the labeled hypothetical example with one consistent OI snapshot. Do not mix expirations, observation dates, or deliverables.
- Enter each strike once with nonnegative whole-contract call and put OI. Set the common cash multiplier; standard US equity options commonly use 100.
- Read total OI and the put/call OI ratio as descriptions of this input sample. Highlighted concentrations use an arbitrary 1.5× mean threshold.
- Inspect the intrinsic payout table and minimum range. The calculation does not predict a settlement price.
Minimum payout is different from profit
For settlement S and strike K, the worksheet sums OI × multiplier × max(S−K, 0) for calls and OI × multiplier × max(K−S, 0) for puts. This convex piecewise-linear total can have a single minimum or a flat interval. It ignores premiums and hedges, so it cannot measure participant profit or establish an incentive that determines price.
Only the entered contracts contribute. Omitted strikes change the result. An all-zero chain is uninformative; a put-only chain has zero intrinsic payout above its highest occupied strike, and a call-only chain below its lowest occupied strike. Maximum-OI ties display the lowest tied strike in the summary.
Frequently asked questions
What data should I enter?
Use a single underlying, expiration, observation date, settlement convention, and common cash multiplier. Enter each strike once. Defaults are a hypothetical example, not market data. Adjusted contracts with noncash deliverables are outside this model.
Does high OI identify support, resistance, or sentiment?
No. OI counts outstanding contracts, with a long and short side for each. This page marks concentrations above 1.5 times the entered average as a descriptive threshold, not a validated price barrier or trading signal.
What does the put/call ratio mean?
It is total entered put OI divided by total entered call OI. Zero call OI makes the ratio undefined. It does not identify whether puts or calls were bought, sold, hedged, or part of a spread.
What does max pain calculate?
It minimizes the sum of call and put intrinsic payout weighted by entered OI and the common multiplier for nonnegative settlement prices. It is not the number of worthless contracts, net trader profit, or a forecast. Flat minimum intervals are shown as ranges; put-only data can have an unbounded upper range.
How current is the data?
This calculator makes no market-data request. Replace the example with a consistent provider OI snapshot and check its observation date. OI is commonly published for the preceding trading day; it is different from intraday volume.
OIC: open interest definition and interpretation
This is a manual educational calculation, not a live OI tracker or investment recommendation. Check the source snapshot date and contract specifications before using the output.