Calculate the spread against the midpoint
The displayed formula is ask minus bid. Percentage spread divides that difference by the midpoint of the two quotes, then multiplies by 100. With a hypothetical $2.30 bid and $2.50 ask, the midpoint is $2.40, the spread is $0.20 and the percentage is 8.33%.
Buying ten standard 100-share contracts at that ask and immediately selling them at the unchanged bid would lose $200 before fees: 10 × 100 × $0.20. This is a deliberately simplified round-trip example. It is not a prediction of actual fills, and it does not mean every entry or exit costs a full spread.
A midpoint is not a promised execution price
A limit order specifies an acceptable price but may not fill. A market order prioritizes execution and may fill at a different price from the displayed quote. Quote size, routing, market movement and order size affect what is available when an order arrives.
For a multi-leg order, the natural price uses the relevant ask for purchased legs and bid for sold legs; it is not the midpoint. Complex-order execution can differ from buying and selling each leg separately. This tool analyzes individual contracts and does not price a multi-leg execution.
Read the sample and quote status
The request returns at most 250 contracts. Choose an expiration and strike range to make the sample relevant, then press Analyze Spreads again. Sorting and the maximum-spread control act on the loaded rows. A changed input does not change the identity of a previously loaded sample.
Missing, negative, non-finite and crossed bid/ask pairs are excluded. A zero bid with a positive ask remains visible and produces a 200% midpoint-relative spread. Equal positive bid and ask produce a zero spread and a locked-quote label; this does not establish that a trade can execute at that price.
Quote time and the provider’s timeframe label appear in the table. Retrieval time is separate. An unavailable timestamp cannot establish freshness. Missing quote sizes, volume and open interest remain missing rather than becoming zero. Open interest describes outstanding contracts after clearing, not immediately executable depth.
Compare contracts without an invented quality score
The 2% and 5% color boundaries are display conventions. There is no universal acceptable spread percentage: premium, tick size, desired order size and strategy constraints matter. The table reports measurements rather than an unvalidated liquidity score. Verify a current executable quote with your broker before making an order decision.