Key Takeaways
- A footprint chart shows, at every price level inside a single bar, the volume executed at the bid versus the volume executed at the ask, usually printed as a small "bid x ask" number pair.
- A standard OHLC bar or candle only shows the bar's open, high, low, and close; it has no within-bar detail. A footprint adds exactly that layer.
- Building a footprint requires trade-by-trade data classified as bid-side or ask-side, not just OHLC bar data.
- Large imbalances between bid and ask volume at a price level are often color-coded and used to flag where aggressive orders concentrated. This is a signal to investigate, not a guarantee of what happens next.
- Footprint/order-flow analysis is a commonly cited but contested and largely discretionary methodology; it is generally used alongside price structure and other context, not in isolation.
What Is a Footprint (Bid x Ask) Chart?
A footprint chart is a chart overlay that shows, for each price level traded within each individual bar, the volume executed at the bid side versus the volume executed at the ask side, often displayed as a small "bid x ask" pair of numbers at each price level within the bar, sometimes color-coded by imbalance. This reveals where aggressive buying or aggressive selling concentrated within a single bar's price range, in contrast to a standard OHLC bar or candle, which only shows the bar's overall open/high/low/close without this within-bar detail.
Put another way: a candlestick tells you where a bar opened, how high and low it traveled, and where it closed. It does not tell you how the volume inside that range was distributed across price levels, or which side of the trade, buyers hitting the ask, or sellers hitting the bid, was more aggressive at each level. A footprint chart fills in that gap by stacking bid-side and ask-side volume at every price the bar touched.
How a Footprint Chart Is Built
Classifying each trade
Every individual trade printed on the tape executes at either the prevailing bid price or the prevailing ask price (a trade cannot execute above the ask or below the bid in a normal continuous market). A footprint chart's underlying data feed classifies each trade this way: a trade that prints at the bid is counted as bid-side (aggressive selling, a seller crossed the spread, or was matched against a resting buy order), and a trade that prints at the ask is counted as ask-side (aggressive buying, a buyer crossed the spread, or was matched against a resting sell order).
Aggregating by price level, within the bar
For a chosen bar (a time bar, a tick bar, or a volume bar, depending on the platform), the chart sums bid-side volume and ask-side volume separately at every discrete price level the bar traded through. Each price level then shows a "bid x ask" pair, for example, "120 x 340" meaning 120 units traded at the bid and 340 units traded at the ask at that specific price during that specific bar.
Displaying the result
Instead of a single candle body, the footprint renders as a small grid stacked vertically along the bar's price range, with two numbers (or two color-scaled cells) at each level. Some platforms additionally color-code a level when the ratio between one side and the other passes a chosen imbalance threshold, making the most lopsided levels visually stand out from the rest of the bar. Because this requires trade-by-trade classification rather than only open/high/low/close values, footprint charts depend on tick or Level 2 data feeds, see Level 1 vs. Level 2 market data for how that underlying data differs from a simple last-price feed.
How It Looks: A Worked Example
Hypothetical example, for education only.
Consider a single 5-minute bar for a hypothetical stock that trades from $50.00 up to $50.04 and back down to close near $50.02. A standard candle for this bar would show only: open $50.00, high $50.04, low $50.00, close $50.02. A footprint view of the same bar might show the following bid-volume-x-ask-volume detail at each price level the bar touched:
| Price level | Bid volume (aggressive sell) | Ask volume (aggressive buy) | Bid x ask |
|---|---|---|---|
| $50.04 (bar high) | 40 | 210 | 40 x 210 |
| $50.03 | 90 | 480 | 90 x 480 |
| $50.02 (bar close) | 260 | 310 | 260 x 310 |
| $50.01 | 150 | 140 | 150 x 140 |
| $50.00 (bar open/low) | 380 | 120 | 380 x 120 |
Read as a standalone candle, this bar simply looks like a modest up bar. Read as a footprint, a different story appears inside it: ask-side (aggressive buying) volume was heavily dominant at $50.03 (480 vs. 90) as price pushed toward the high, while bid-side (aggressive selling) volume was dominant back down at $50.00 (380 vs. 120), meaning a wave of aggressive selling met the bar's low before it turned back up to close mid-range. A trader reading only the candle would see "up bar, closed mid-range." A trader reading the footprint sees the same bar as a tug-of-war between aggressive buyers pushing the high and aggressive sellers defending the low, with neither side fully winning by the close.
How Traders Use It
Imbalance levels
Traders commonly look for price levels where one side's volume is disproportionately larger than the other, a heavy skew toward one side, often flagged once it crosses a ratio threshold set by the platform or the trader, and treat a cluster of such imbalanced levels as a sign that aggressive orders concentrated there. This is typically read alongside where the level sits in the bar (near the high, the low, or mid-range) rather than in isolation.
Absorption
Some footprint users watch for "absorption", a level where a large volume of aggressive orders on one side traded without price continuing to move in that direction, suggesting a resting counter-order absorbed the aggression at that level. As with imbalance. This is a pattern some traders treat as informative, not a confirmed signal of what happens next.
Comparing footprint to the candle shape
Because a footprint shows detail a candle alone cannot, traders sometimes compare the two directly: a candle that looks unremarkable can still contain a lopsided footprint (as in the worked example above), and a candle with a dramatic range can sometimes contain a relatively balanced footprint. The footprint is generally used as an additional layer of context on top of price structure, volume, and other tools, not as a replacement for them.
Limitations and Common Mistakes
- No single pattern guarantees an outcome. Footprint and order-flow reading is a commonly cited but contested and largely discretionary methodology, the same imbalance or absorption pattern has been followed by continuations, reversals, and non-events across different instances, and no fixed rule reliably distinguishes them in advance.
- Data quality and classification vary by feed and venue. Whether a trade is correctly classified as bid-side or ask-side depends on the accuracy and latency of the underlying tick/Level 2 feed; different platforms and different data providers can produce visibly different footprint detail for the same bar.
- Reading footprints in isolation, without broader context. A single imbalanced level, viewed without the surrounding bars, prior price structure, or the instrument's typical liquidity, is easy to over-interpret.
- Treating the footprint as a full picture of the order book. A footprint reflects executed trades classified by side, not the full resting order book, it says nothing about hidden or iceberg orders, or about liquidity that was posted but never traded against. See displayed vs. hidden liquidity for more on that distinction.
- Assuming footprint granularity is available everywhere. Because it depends on tick-level classification, footprint detail is generally not available on instruments or platforms limited to OHLC bar data alone, and can be noisier or less reliable on thinly traded instruments than on liquid ones.
What a Bar Full of Numbers Still Does Not Say
A footprint bar answers where inside the bar trading happened and against which side of the quote. It does not answer who was trading or why, and a display this detailed invites reading intent into arithmetic. The numbers are a record of executions, and every execution had two sides.
The reading that holds up is structural. Noticing that activity concentrated at one end of a bar, or thinned where it had previously been heavy, describes how the period was distributed. Converting that into an expectation about the next bar adds an assumption the display does not supply.
Classification matters here as much as anywhere. Which side a trade is attributed to depends on a rule applied by the data provider, so the same session rendered by two platforms can disagree in its detail while agreeing on the totals.
Coverage is the other boundary. Volume printing away from the visible market, or reported on a different basis, may be absent or misplaced, and the bar shows what the feed carried rather than everything that traded.
Frequently Asked Questions
What is a footprint chart in simple terms?
A footprint chart is a chart overlay that shows, for each price level traded within each individual bar, the volume executed at the bid side versus the volume executed at the ask side, often displayed as a small "bid x ask" pair of numbers at every price level inside the bar. It reveals where aggressive buying or aggressive selling concentrated within a single bar's range, something a standard OHLC bar or candle cannot show.
How is a footprint chart different from a regular candlestick chart?
A standard candle only shows a bar's overall open, high, low, and close. A footprint chart adds within-bar detail: at each individual price level the bar traded through, it shows the split between volume executed at the bid and volume executed at the ask. Two bars with an identical candle shape can have very different footprints underneath.
What does a bid x ask imbalance mean on a footprint chart?
An imbalance is a price level where volume on one side (commonly ask volume relative to the bid volume one tick below, or vice versa) is disproportionately larger than the other, a heavy skew toward one side, often highlighted with color coding once it crosses a chosen ratio threshold set by the platform or trader. It flags where aggressive orders concentrated at that level, it does not by itself confirm that price will continue in that direction.
Do footprint charts require Level 2 or tick-level data?
Yes. Building a footprint chart requires trade-by-trade (tape) data with enough detail to classify each execution as bid-side or ask-side, which most retail charting platforms source from a tick or Level 2 data feed rather than the OHLC-only bar data used for standard candlestick charts.
Are footprint charts reliable for predicting price direction?
No single footprint pattern guarantees a future outcome. Footprint analysis is a commonly cited order-flow methodology among discretionary and short-term traders, but it remains contested and largely discretionary, the same imbalance or absorption pattern can precede a reversal, a continuation, or nothing at all, depending on broader context.
Is a footprint chart the same thing as a volume profile?
No. A volume profile aggregates total traded volume by price across a chosen window (a session, a range, or a chart's full history) into one horizontal histogram. A footprint chart keeps every individual bar separate and splits each bar's volume at each price level into bid-side and ask-side components. Some platforms display both together, but they answer different questions.
How does the bar interval change what a footprint chart shows?
A footprint aggregates trades within each bar, so a longer interval combines more activity into each cell and smooths the imbalances, while a shorter one produces sparse cells dominated by individual trades. The same session viewed at two intervals can suggest different pictures. Because the interval is chosen rather than given, it belongs alongside any observation drawn from the chart.
What happens to a footprint chart when a large trade is reported late?
Trades reported outside the normal sequence can be attributed to the bar in which they were reported rather than the one in which they occurred, which places volume at a price level where it did not trade in that interval. Platforms differ in how they handle late reports and trade conditions. The effect is largest in less active securities, where one misplaced block can dominate a bar.
Does the same footprint pattern mean the same thing across different instruments?
The construction depends on classifying trades by side, and the reliability of that classification varies with how much of an instrument's volume trades at the quote versus between it or off-exchange. In a centrally traded futures contract nearly all volume is classifiable; in a fragmented equity market a meaningful share is not. The same visual pattern therefore rests on different amounts of underlying certainty.
References
- CMT Association: Technical Analysis Body of Knowledge and Research
- CFA Institute Research and Policy Center: Investment Research
- TA-Lib: Technical Analysis Function Library Documentation
- SEC Investor.gov: Introduction to Investing
Assumptions in this article: The worked example's bid/ask volume figures are hypothetical and constructed for illustration only. They do not represent actual market data for any real instrument.
Educational Disclaimer
For education only; not personalized investment, tax, or legal advice. Trading can result in substantial losses.
Charting platforms, data feeds, and available order-flow tools vary and can change. Verify current capabilities with your broker or charting platform before relying on any specific footprint implementation.