How to Read a Footprint Chart

A candlestick tells you four prices: where a bar opened, how high it went, how low it went and where it closed. It says nothing about what happened in between. Two candles can look identical while one was built by aggressive buyers lifting offers all the way up, and the other by a handful of trades in thin conditions.

A footprint chart opens the candle up. Inside each bar it shows every price that traded and how many contracts changed hands there, split into what buyers took at the ask and what sellers hit at the bid. Once you can read it, a bar stops being a shape and becomes a record of an auction.

This guide walks through a footprint bar from the outside in: where its numbers come from, how the columns are laid out, and what to look at first.

What a Footprint Chart Is

A footprint chart (also called a volume footprint, a bid/ask chart or a cluster chart) draws each bar as a column of prices, one row per tick. Every row holds two numbers:

• Bid volume: contracts that traded at that price when a seller crossed the spread and sold into a resting buy order.
• Ask volume: contracts that traded at that price when a buyer crossed the spread and bought from a resting sell order.

The bar's range is the same as the candle's. What changes is that you can now see the volume distributed across that range and who was the aggressor at each price.

The footprint is built from the exchange's trade data, so it works on any bar type that is built from trades: time bars, tick bars, volume bars, range bars and Renko. The bar type changes how the trades are grouped. The reading rules stay the same.

Where the Numbers Come From

Every trade on an electronic futures market has two sides: a resting order that was already on the book, and an incoming order that matched against it. The incoming order is the aggressor. It is the side that decided the trade had to happen now and accepted the other side's price.

CME Group's market data feed labels this directly. Its trade summary messages carry an AggressorSide field that says whether the buyer or the seller was the aggressor, or that there was no aggressor. A footprint built from that field does not have to guess which side started each trade.

That gives the two columns their meaning:

• A trade where the buyer was the aggressor took liquidity from sellers resting on the offer, so it prints in the ask column.
• A trade where the seller was the aggressor took liquidity from buyers resting on the bid, so it prints in the bid column.

This is the single most common point of confusion for new footprint readers. A large number in the bid column does not mean buyers were active. It means sellers were hitting the bid, and the buyers there were passive: their limit orders absorbed the selling.

Some data sources do not carry the aggressor flag and have to infer it by comparing each trade's price with the best bid and offer at the time. That inference is usually right in a liquid market and less reliable in a fast one. Knowing which kind of data your footprint uses tells you how much weight to put on a single print.

Reading One Bar, Row by Row

Here is a single five-minute ES bar drawn as a footprint. The numbers are an invented illustration, rounded to keep the arithmetic easy. They are not from a real session.

Price	Bid (sold)	Ask (bought)
5,804.00	20	0
5,803.75	60	90
5,803.50	110	240
5,803.25	180	410
5,803.00	300	520
5,802.75	260	280
5,802.50	150	120
5,802.25	90	30
5,802.00	30	10

The bar opened near 5,802.50, traded down to 5,802.00, then rallied to 5,804.00 and closed near 5,803.75. On a candle chart it would be a green bar with a small lower wick. The footprint shows considerably more.

Rows are ticks. ES has a minimum price increment of 0.25 index points, worth $12.50 per contract, so each row is one tick apart. In NQ the increment is also 0.25 index points, worth $5.00 per contract.

Read the columns diagonally as well as across. In each row the bid number and the ask number traded at the same price but against different resting orders. A buyer lifting the offer at 5,803.25 and a seller hitting the bid at 5,803.00 were facing the same spread at the same moment. That is why imbalance calculations compare numbers diagonally (ask at one price against bid one tick below), which is a topic of its own.

Total Volume

Add both columns of every row:

• Bid total: 20 + 60 + 110 + 180 + 300 + 260 + 150 + 90 + 30 = 1,200
• Ask total: 0 + 90 + 240 + 410 + 520 + 280 + 120 + 30 + 10 = 1,700
• Bar volume: 1,200 + 1,700 = 2,900 contracts

Delta

Delta is ask volume minus bid volume: buying aggression minus selling aggression.

Bar delta = 1,700 - 1,200 = +500

A positive delta of 500 says that over this bar, aggressive buyers took 500 more contracts than aggressive sellers. It does not say the bar will be followed by higher prices. It says who was pushing while it formed.

Delta is most useful against what price did. A bar that closes up with strong positive delta is internally consistent: buyers pushed and price moved. A bar that closes up with negative delta, or closes down with strong positive delta, deserves a second look, because the aggression and the result disagree.

The Point of Control

The point of control (POC) of a bar is the price with the most total volume. Add bid and ask in each row:

Price	Total
5,803.25	590
5,803.00	820
5,802.75	540

In this bar the POC is 5,803.00, with 820 contracts. That is where the bar did most of its business, the price both sides found most acceptable during those five minutes.

Where the POC sits within the bar matters. A POC near the top of an up bar means the heaviest trading happened at the higher prices: the market accepted them. A POC near the bottom of an up bar, with thin volume above it, means price moved up but did not build much trade there, which often makes those upper prices less settled.

Value Area of a Bar

Some footprints also mark a bar's value area: the range of prices around the POC that holds a set share of the bar's volume, commonly 70%. It is built the same way a session volume profile's value area is built, just inside one bar. In our example, the rows from 5,802.75 to 5,803.50 hold 540 + 820 + 590 + 350 = 2,300 of 2,900 contracts, about 79%, so the bar's value sits in that one-point band.

The Extremes: Finished and Unfinished Auctions

The top and bottom rows of a bar are where the auction stopped. They are worth reading on their own.

A common way footprint traders describe them:

• Finished auction at the high: at the bar's highest price, only the bid column has volume. Sellers traded there, but no buyer paid the offer at that price. Buying ran out before the top was extended.
• Unfinished auction at the high: at the bar's highest price, both columns have volume. Buyers were still lifting offers at the top when the bar ended.

The same logic applies at the low, mirrored: a finished low has volume only in the ask column (no seller hit the bid at the lowest price), an unfinished low has volume on both sides.

In our example bar:

• The high at 5,804.00 shows 20 on the bid and 0 on the ask. No buyer paid the offer at the top: a finished auction at the high.
• The low at 5,802.00 shows 30 on the bid and 10 on the ask. Sellers were still hitting bids at the lowest price when buyers turned the bar around: an unfinished auction at the low.

Conventions differ slightly between traders and tools (some also require a minimum volume before calling an extreme unfinished), so check how yours defines it.

Traders watch unfinished auctions because markets often return to them. The thinking is that an auction that ended with both sides still trading at its extreme did not find the price where one side gave up. Many footprint tools draw a line from an unfinished extreme until price trades back through it. Treat that as a reference level, not a prediction: some unfinished auctions get revisited within minutes, some never do.

What to Look at First

A footprint chart carries a lot of numbers. Reading every one of them in real time is not realistic, and it is not necessary. A practical order:

1. The Bar's Delta Against Its Close

Is the aggression consistent with where the bar closed? Agreement is normal. Disagreement is a flag to look closer.

2. Where the Point of Control Sits

Top, middle or bottom of the bar. This tells you where the bar's business was done and whether the move built acceptance.

3. The Extremes

Is the high or low finished or unfinished? Are the extreme rows unusually heavy or unusually thin?

4. Rows That Stand Out

Prices where one column is many times the other, or where total volume is far above the rows around it. These are where the footprint's imbalance and absorption readings come from.

5. The Bar in Context

A single bar is a small sample. What matters more is how its readings relate to the bars before it and to the levels you already care about: the prior day's high and low, the session's value area, a level that held earlier.

Reading Absorption

One of the most useful things a footprint shows is absorption: heavy aggressive volume at a price that does not move price.

Consider another invented illustration. ES trades down into 5,790.00, a level that held the day before. Over two bars, the bid column at 5,790.00 and 5,790.25 fills with 900 and 750 contracts of selling. Price does not trade below 5,790.00. The next bar opens at 5,790.50 and the low holds.

What happened: sellers crossed the spread and sold 1,650 contracts into those two prices, and resting buyers took all of it without the bid giving way. Aggressive selling met passive buying that was large enough to stop it. A candle chart shows a level holding. The footprint shows that it held against real selling, not because nobody tested it.

The reverse also matters. If price falls through 5,790.00 on modest bid volume, the level gave way without much effort, which says something different about who was there.

Absorption is a description, not a signal. Passive buyers can absorb for a while and then step away, and the level breaks anyway. What the footprint gives you is evidence about how a level is being defended, which you can weigh alongside everything else.

Statistics Under the Bars

Most footprint charts can show a small table beneath each bar so you do not have to add columns in your head. Common rows:

• Volume: total contracts in the bar.
• Delta: ask volume minus bid volume.
• Max delta and min delta: the highest and lowest running delta reached while the bar was forming. A bar that closed at +500 but reached +1,100 along the way gave back more than half its buying by the close.
• Delta percent: delta divided by volume. In our example, 500 / 2,900 = about 17%. This puts bars of different sizes on the same scale: +500 on a 2,900-contract bar is a stronger lean than +500 on a 12,000-contract bar.
• Cumulative delta: the running total of delta across bars, usually reset at the start of a session.

These numbers make comparisons across bars quick. A run of bars with rising price and shrinking delta percent, for example, says the move is continuing with less aggression behind each step.

Bar Type Changes the Picture

The same trades grouped differently produce different footprints.

• Time bars group trades by the clock. A five-minute bar at the open can hold ten times the volume of a five-minute bar at lunch, so footprints on time bars are naturally uneven.
• Tick bars close after a set number of trades. Each bar represents the same amount of activity measured in trades, regardless of how large each trade is.
• Volume bars close after a set number of contracts. Every bar has the same total volume, which makes delta and row sizes directly comparable from one bar to the next.
• Range bars and Renko close when price has moved a set distance. Every bar covers a similar number of rows, which keeps the footprint's shape regular and emphasizes how much trading it took to move price that far.

None of these is correct and the others wrong. They answer different questions. A trader who wants to compare aggression across bars may prefer volume bars. A trader who wants the footprint aligned with clock-based levels may prefer time bars.

Common Mistakes When Reading a Footprint

Reading the bid column as buyers. It is sellers hitting the bid. The buyers there were passive.

Treating delta as direction. Positive delta means more aggressive buying than selling during the bar. Price can still fall afterwards, and frequently does when that buying was absorbed by large passive sellers.

Reading a single print as meaning. One large row on its own is noise more often than it is information. Look for readings that repeat across rows or bars, or that occur at a level you already had reason to watch.

Ignoring the session's context. A footprint at the open, during a scheduled economic release, or in thin overnight trade behaves differently from one at midday. The same row sizes mean different things at different times of day.

Zooming out until the numbers are unreadable. Footprints need horizontal room. Zoomed out, the numbers turn into a blur. A footprint that switches to shading or a per-bar profile when bars get narrow keeps the information readable instead of drawing digits too small to see.

A Short Checklist

When a footprint bar catches your attention, run through these in order:

1. Columns: bid is sellers hitting bids, ask is buyers lifting offers. Have you read them the right way round?
2. Delta: does the bar's delta agree with its close? If not, why?
3. Point of control: where in the bar did most of the trading happen?
4. Extremes: is the high or the low unfinished, with volume on both sides?
5. Standouts: any rows with one side several times the other, or volume far above its neighbors?
6. Location: is this happening at a level that mattered before?
7. Bar type: are you comparing like with like, or are time bars making some bars look heavier than others?

The Bottom Line

A footprint chart does not tell you what the market will do. It tells you, in detail, what the market just did: at which prices contracts traded, which side was aggressive, where the bar did most of its business and whether the auction at each extreme ran out of participants.

That detail is what turns a candle into evidence. Read the columns the right way round, start with delta, the point of control and the extremes, and give individual numbers less weight than readings that repeat across rows and bars. The skill is in putting what the footprint shows next to where it is happening.

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NexTick360's footprint shows bid and ask at every price, imbalances in bold, each bar's point of control boxed, unfinished auctions dashed until they are revisited and statistics under the bars, and stays readable zoomed out as rows merge, then shade, then become a profile in the candle, on time, tick, volume, range and Renko bars built from your broker's trades. See the order flow tools