Metric glossary - what every column means
Plain-English definitions and the exact formulas behind every screener and report column - IV, IV rank, open interest, volume/OI, put/call ratio, money flow, the Greeks and more.
Reviewed 2026-11-02
Overview
Every column you can filter, sort or alert on is listed here: what it means, how OptionsScreenerPro computes it and what to keep in mind when you read it. In the screeners and reports, hover or tap the small ⓘ next to a column header to see the definition, the formula and the main caveat, then choose Read more to jump straight to its entry.
A few rules hold for every number:
- Delayed data is labelled delayed. Quotes come from free or delayed providers; the freshness badge says how old they are. See Understanding data freshness.
- Unknown is "-", never 0. When a baseline is missing (a new listing, the first session of history), the cell shows "-" and the tooltip says why.
- Activity is gross. Volume, money flow and the put/call ratios count contracts and premium traded. They never say whether a trade was a buy or a sell, opening or closing, bullish or bearish.
Contract and identity
| Column | Meaning | How it is computed |
|---|---|---|
| Symbol | The ticker of the stock, ETF or index (for an option, its underlying). | - |
| Instrument type | Stock, ETF or index. | - |
| Exchange | The primary listing exchange. | - |
| Right | Call or put. | - |
| Expiration | The date the contract expires. | - |
| Days to expiry | Calendar days until expiration (DTE); 0 = expires today (0DTE). | expiration date - today |
| Strike | The price at which the option buys (call) or sells (put) the underlying. | - |
| Moneyness | How far the strike is from the underlying price. | (strike - underlying) / underlying |
| Moneyness class | In the money (ITM), at the money (ATM) or out of the money (OTM). | - |
| In the money | True when exercising now would have value. | call: price > strike; put: price < strike |
Prices and premium
| Column | Meaning | How it is computed |
|---|---|---|
| Bid | Highest price a buyer offered at the quote time. | provider quote |
| Ask | Lowest price a seller offered at the quote time. | provider quote |
| Last | Price of the most recent trade (can be stale on thin contracts). | provider quote |
| Mark | The bid/ask midpoint, OSP's reference price. | (bid + ask) / 2 |
| Spread | Ask minus bid. | ask - bid |
| Spread % | The spread as a share of the mark. | (ask - bid) / mark |
| Premium | Cost of one contract at the mark. | mark x 100 |
| Break even | Underlying price at expiry where a buyer breaks even. | call: strike + mark; put: strike - mark |
| Premium traded | Estimated dollars traded in the contract this session. | volume x average traded premium x 100 |
| Avg premium (traded) | Average mark over the session snapshots in which the contract traded. | average(mark) where volume > 0 |
Volume and open interest
| Column | Meaning | How it is computed |
|---|---|---|
| Volume | Contracts (or shares) traded so far this session. | provider quote |
| Open interest | Contracts still open at the previous settlement (OI); updates once a day. | clearing-house figure |
| Volume / OI | Today's volume against yesterday's open interest. | volume / open interest |
| Volume change % | Today's volume against the previous session's closing volume. | (volume - previous volume) / previous volume |
| OI change % | Change in open interest since the prior settlement. | (OI - prior OI) / prior OI |
| OI change | The same change in contracts. | OI - prior OI |
| Avg volume (20d) | Average daily volume over the last 20 sessions. | mean of 20 sessions |
| Relative volume | Today's volume as a multiple of the 20-session average (RVOL). | volume / 20-day average |
Implied volatility
| Column | Meaning | How it is computed |
|---|---|---|
| Implied volatility | The yearly volatility the option's price implies (IV); 0.35 = 35 %. | solved from the option price by the provider |
| IV rank | Where today's IV sits between its 52-week low (0 %) and high (100 %) (IVR). | (IV - 52w low) / (52w high - 52w low) |
IV rank needs a year of history, so a newly listed symbol shows "-" until that history exists.
The Greeks
| Column | Meaning |
|---|---|
| Delta | Expected option price move for a 1-dollar move in the underlying. Calls positive, puts negative. |
| |Delta| | Delta without its sign, so one range filters calls and puts alike. |
| Gamma | How fast delta changes when the underlying moves 1 dollar. |
| Theta | Expected daily loss of value from time passing (time decay). |
| Vega | Expected price change for a 1-point change in implied volatility. |
| Rho | Expected price change for a 1-point change in interest rates. |
Greeks come from the market-data provider, and providers can differ slightly in how they compute them.
Underlying and stock
| Column | Meaning | How it is computed |
|---|---|---|
| Underlying price | Last price of the stock the option is written on. | provider quote |
| Underlying change % | The underlying's move since the prior close. | (last - prior close) / prior close |
| Underlying volume | Shares of the underlying traded this session. | provider quote |
| Change | Move since the prior close, in dollars. | last - prior close |
| Change % | Move since the prior close, as a fraction. | (last - prior close) / prior close |
| Open | First traded price of the session. | - |
| High | Highest price of the session so far. | - |
| Low | Lowest price of the session so far. | - |
| Previous close | Close of the previous session. | - |
| Market cap | Market value of the shares outstanding. | shares outstanding x last |
| Has options | At least one option series is listed. | - |
| Gap % | How far the session opened from the previous close. | (open - previous close) / previous close |
| Open-to-last % | Move from the open to the latest price. | (last - open) / open |
| At session high | Latest price is at or above the session high. | - |
| At session low | Latest price is at or below the session low. | - |
Chain totals and ratios
| Column | Meaning | How it is computed |
|---|---|---|
| Put/call ratio (volume) | Put volume divided by call volume across the chain (PCR). | sum(put volume) / sum(call volume) |
| Put/call ratio (OI) | Put open interest divided by call open interest. | sum(put OI) / sum(call OI) |
| Total option volume | Contracts traded across every option on the symbol. | sum over the latest snapshot of each contract |
| Total open interest | Open contracts across every option on the symbol. | sum of OI |
| Call volume (chain) | Calls traded across the chain. | sum |
| Put volume (chain) | Puts traded across the chain. | sum |
| Call OI (chain) | Open call contracts across the chain. | sum |
| Put OI (chain) | Open put contracts across the chain. | sum |
| Call volume share | Share of the chain's volume that was calls - an activity share, not a direction signal. | call volume / (call + put volume) |
| Chain average IV | Average IV across the chain for the session. | mean IV |
Session moves and surges
| Column | Meaning | How it is computed |
|---|---|---|
| Previous session volume | Closing volume of the previous session (the surge baseline). | - |
| Volume change | Today's volume minus the previous session's. | volume - previous volume |
| Volume surge ratio | Today's volume as a multiple of the previous session's. | volume / previous volume |
| Volume vs 20d avg % | Today's volume against its 20-session average. | (volume - 20d avg) / 20d avg |
| Unusual volume | Volume more than twice its 20-session average and above open interest (unusual options activity, UOA). | volume > 2 x 20d avg AND volume > OI |
| Previous session OI | Open interest at the previous session's close. | - |
| OI surge ratio | Open interest as a multiple of the previous session's. | OI / previous OI |
| Previous session IV | IV at the previous session's close. | - |
| IV change (points) | IV change since the previous session, in points (0.03 = 3 points). | IV - previous IV |
| IV change % | Relative IV change since the previous session. | (IV - previous IV) / previous IV |
| IV surge ratio | IV as a multiple of the previous session's. | IV / previous IV |
| IV at session open | First IV observed this session. | - |
| IV session high | Highest IV observed this session. | - |
| IV session low | Lowest IV observed this session. | - |
| IV change intraday (points) | IV move since the first snapshot of the session. | IV - IV at open |
| IV call - put (same strike) | Call IV minus put IV at the same strike and expiry. | IV(call) - IV(put) |
Money flow
| Column | Meaning | How it is computed |
|---|---|---|
| Money flow (chain) | Estimated dollars traded across the chain, calls and puts added. | sum of volume x mark x multiplier |
| Call money flow (chain) | The same for calls only. | sum over calls |
| Put money flow (chain) | The same for puts only. | sum over puts |
| Money flow share | This contract's share of the premium traded across its chain. | premium traded / chain money flow |
| Call minus put money flow | Call money flow minus put money flow. | call flow - put flow |
Money flow is an approximation from the mark, not from individual trade prices. It is gross: calls and puts are added, never netted, and "call minus put" is a difference in premium traded - not buying versus selling and not a bullish or bearish signal.
Strategy columns
| Column | Meaning | How it is computed |
|---|---|---|
| Intrinsic value | The in-the-money part of the option price, per share. | call: max(price - strike, 0); put: max(strike - price, 0) |
| Extrinsic value | Time and volatility value above intrinsic. | mark - intrinsic, floored at 0 |
| Multiplier | Shares per contract (100 for standard contracts). | contract terms |
| Straddle price | Cost of the call plus the put at the same strike and expiry, per share. | mark(call) + mark(put) |
| Put premium (pair) | The put's mark at this strike and expiry. | - |
| Straddle price per contract | The straddle for one contract of each leg. | straddle price x multiplier |
| Straddle required move % | The move needed by expiry for a straddle buyer to break even, often read as the "expected move". | straddle price / underlying price |
| Vertical width | Distance to the next strike further out of the money, same right and expiry. | strike difference |
| Vertical credit (1 strike) | Credit for selling this option and buying the next strike out, per share. | mark(this) - mark(next out) |
| Vertical credit / width | Credit collected per dollar of width. | credit / width |
Example (invented numbers)
Sample symbol XYZ trades at 50.00. Its 50-strike call has a mark of 1.20 and the 50-strike put a mark of 1.05. The Straddle price is 1.20 + 1.05 = 2.25, the Straddle price per contract is 225.00, and the Straddle required move % is 2.25 / 50.00 = 4.5 %.
Data quality and eligibility
| Column | Meaning | How it is computed |
|---|---|---|
| Quote quality | realtime, delayed, end of day, indicative or derived. | snapshot provenance |
| Quote delay (s) | The provider's delay in seconds; 0 = realtime. | snapshot provenance |
| Session snapshots | Snapshots captured for the contract this session; a low count marks a partial session. | count |
| Liquidity eligible | The default filter that hides contracts too thin to rank. | (OI >= 100 OR volume >= 10) AND bid > 0 |
| Live contract | Traded or carries open interest this session. | volume > 0 OR OI > 0 |
| Monthly expiration | The standard third-Friday monthly (Thursday when that Friday is a holiday). | calendar rule |
FAQs
Why does a column show "-" instead of a number?
The value cannot be computed honestly: the previous-session baseline is missing, the other leg of a pair has no quote, or there is not yet enough history (IV rank needs a year). Hover the cell for the reason.
Is "Unusual volume" a buy signal?
No. It only says that unusually many contracts traded; it cannot tell buyers from sellers or opening from closing trades.
Troubleshooting
The numbers differ from my broker's
Brokers show realtime quotes; OptionsScreenerPro shows delayed or end-of-day data, and Greeks and IV depend on the provider's model. Check the freshness badge on the page.