A footprint chart opens up each candle and shows the volume traded at every price inside it, split into two numbers: volume that hit the bid (aggressive sellers) and volume that lifted the ask (aggressive buyers). It is the most detailed view of order flow most traders will use.
Bid vs ask
Every trade has a buyer and a seller, so volume itself can't be "buying" or "selling". What the footprint shows is who was aggressive: a market buy order trades at the ask (counted on the right), a market sell order trades at the bid (counted on the left). The passive side was a resting limit order.
What to look for
| Pattern | What it looks like | Common reading |
|---|---|---|
| Diagonal imbalance | Ask volume ≥ 3× the bid volume one tick lower (or the mirror for selling) | One side was far more aggressive; stacked imbalances show strong intent |
| Absorption | Heavy aggressive volume at an extreme, but price doesn't move further | Large passive orders are soaking it up; a reversal may follow |
| Exhaustion | Very little volume at the extreme of a move | No one left to push; the move may be ending |
| Unfinished auction | Both bid and ask volume at the very high or low | Price often comes back to finish trading there |
Reading the example
Near the low, sellers hit the bid hard (140 and 210 contracts) but price closed near the top of the candle. That selling was absorbed by passive buyers. Higher up, three stacked buying imbalances show buyers lifting offers aggressively. Together they suggest a bullish candle with real demand behind it.
Key takeaways
- A footprint chart shows bid and ask volume at every price inside each candle.
- Ask volume is aggressive buying; bid volume is aggressive selling.
- Diagonal imbalances, absorption, exhaustion and unfinished auctions are the main patterns.
- Use footprints on futures to confirm reactions at levels chosen in advance.