A Fair Value Gap and an order block are chart-reading concepts found in Smart Money Concepts discussions. Neither label reveals a complete order book or proves the presence of unfilled institutional orders. A gap drawn between candles and an area selected before a large move are different constructions, even when their rectangles overlap on screen.
Definitions vary among traders. This guide states one FVG rule and one illustrative order-block rule so their boundaries can be checked. These conventions do not establish statistical edge, promise a return visit or identify fair economic value. All price examples below are hypothetical and explain chart geometry rather than a current setup.
A three-candle FVG has a measurable boundary
Number three completed candles 1, 2 and 3. Under the common wick-based bullish convention used here, a gap exists when candle 3's low is above candle 1's high. Its boundaries are candle 1's high and candle 3's low. The bearish convention requires candle 3's high below candle 1's low, using those two prices as the bounds.
Suppose candle 1 has high 100 and low 96, candle 2 has high 108 and low 99, and candle 3 has high 111 and low 103. The bullish FVG is 100–103, width 3. Candle 2's recorded range spans that area, but OHLC does not establish the intrabar path or trades at every intervening price. The construction does not mean no transaction ever occurred there; it describes non-overlap of the outer candles under this rule.
An order block adds selection choices
For illustration, define a bullish order block as the most recent bearish candle before a qualifying upward move. The definition still needs a rule for qualifying, a search distance and a choice of candle body or full range. Different choices can yield different zones. The bearish counterpart selects a bullish candle before a qualifying downward move.
In our fictional sequence, suppose candle 1 opened at 99 and closed at 97, with its range 96–100. A full-range block would be 96–100; a body-only block would be 97–99. Neither equals the 100–103 FVG. Calling the candle an order block is an analyst's chosen label; the OHLC values alone do not prove which institution placed which order.
Compare what each construction requires
| Question | Fair Value Gap | Order block |
|---|---|---|
| Primary construction | Non-overlap of outer candles in a completed three-candle sequence | Selected opposite-direction candle before a qualifying move |
| Boundary choice | Outer-candle wick prices in this guide | Body or full range must be declared |
| Known at what time? | After candle 3 completes | After the qualifying move is confirmed |
| What it cannot prove | Future filling or economic fair value | Participant identity or outstanding institutional orders |
Define a revisit instead of assuming a fill
A return into the 100–103 example can touch its upper edge, reach midpoint 101.5 or traverse the entire area. Those are different observations. Specify which counts as a fill and whether one wick or a completed close is required. A zone can remain untouched, be crossed without a reaction or react only after a large adverse move.
Order-block studies likewise need expiry, invalidation and repeat-visit rules. If the qualifying move needs a confirmed swing break, account for its confirmation delay. Drawing a block at the earlier candle after seeing the breakout does not mean an order could have been placed there using that future information.
Size is descriptive until a rule is tested
A gap width of 3 can be divided by an ATR of 6 to give 0.5 ATR. This normalizes the chosen price distance, but does not establish that this size predicts a better reaction. State the ATR period, timeframe and value available at formation. Selecting a minimum size after reviewing winning examples risks fitting the label to the outcome.
If studying entries on a revisit, specify the first executable order time and an invalidation level, then convert the possible loss into cash. Keep unfilled limits, gaps through the zone and spread changes in the sample. A rectangle that price entered on a chart does not guarantee the broker filled a limit order at the preferred price.
Distinguish an FVG from an IFVG
An inverse FVG convention concerns a previously identified gap that is later crossed and treated as having changed role. It therefore adds a later event to the original construction. Plain FVG detection, order-block selection and inversion are separate rules; performance evidence for one should not be claimed for the others.
The linked IFVG guide discusses that related concept. Keep its particular invalidation or inversion definition beside the plain FVG rule when comparing indicators. A familiar term in a product name does not establish that every implementation draws the same zones or confirms them at the same time.
Frequently asked questions
Must every FVG fill? No; the construction imposes no obligation on future prices. Does an order block prove smart money bought there? No; participant identity requires different evidence. Which is better? A fair comparison needs fixed definitions, matched data, execution assumptions and out-of-sample results; the names alone cannot answer it. Platform documentation below supports candle and order mechanics, not a claim that these SMC concepts have been validated.
A zone-study checklist
- Record formation time and exact completed-candle boundaries.
- Declare the order-block search, qualification and body-versus-range rule.
- Specify expiry, invalidation and what counts as a revisit or fill.
- Keep unvisited zones, failed reactions and unfilled orders in the sample.