Market data disclosure
A calculator that mixes real quotes with generated prices, and does not say which is which, is worse than one with no data at all. This page states exactly where every number on this site comes from.
Last reviewed against the calculator
The three modes
Every calculation on this site runs in one of three modes. The banner above your results always names the one in effect.
- Manual Mode
- You are entering every price yourself. Nothing on this page came from a market data feed.
- Theoretical Mode
- Premiums on this page were generated by the Black-Scholes-Merton model from the volatility and rate you supplied. They are not quotes, and no contract is being offered at these prices.
- Market Data Mode
- Prices came from a market data provider. Check the timestamp and status label beside each quote.
One model-priced leg makes the whole result theoretical
Mode is derived from the data, not from a toggle you set. If any premium in the position came from the pricing model, the banner says Theoretical — because a result that is partly generated is not a real one, and letting it look real is the failure this rule exists to prevent.
What this site is doing right now
This deployment currently offers:
- Manual Mode — You are entering every price yourself. Nothing on this page came from a market data feed.
- Theoretical Mode — Premiums on this page were generated by the Black-Scholes-Merton model from the volatility and rate you supplied. They are not quotes, and no contract is being offered at these prices.
- Market Data Mode — Prices came from a market data provider. Check the timestamp and status label beside each quote.
Live market data is enabled. Where a figure came from the feed, it carries a Market badge and a timestamp, and the banner names the provider.
The badge beside every number
Provenance is tracked through the whole calculation rather than assumed at the end. Each input carries a tag, and the result carries the weakest tag among its inputs.
| Badge | Means | Trust it for |
|---|---|---|
| Yours | You typed it. | Exactly as much as you trust your own input. |
| Market | A data feed supplied it, with a timestamp. | What the market showed at that moment, not necessarily now. |
| Model | Black-Scholes-Merton produced it from your other inputs. | Understanding structure. Never as a tradeable price. |
| Default | A placeholder so the page is not empty. | Nothing. Replace it. |
How fresh is fresh
When live data is on, not everything in an options chain updates at the same rate, and presenting them as if they did would be misleading.
- Quotes and last-traded prices carry the timestamp the feed gave them. A quote from before the close is labelled as such rather than shown as current.
- Open interest is published with a lag of at least one day by the clearing house. It always appears with its as-of date, never as a live figure.
- Greeks and implied volatility are computed here from the feed’s prices rather than taken from the provider, so they are auditable against the stated formulas. Where a provider supplies its own, they are shown as a cross-check and labelled.
If a data request fails, the calculator says so and keeps your inputs. It never substitutes a zero, and it never quietly falls back to a generated price while leaving the Market badge in place.
Why live data is not on by default
Real-time US options quotes come from OPRA, and redistributing them carries licensing obligations that are settled properly or not at all. The provider layer is built, tested and ready; it stays behind a flag until that is in order.
In the meantime the calculator is fully usable, because the mathematics does not depend on where the premium came from. Paste the prices from your broker into Manual Mode and every figure is exact for those inputs. That is the honest version of what a free calculator can promise.