Fill
The actual execution of an order, at the price and quantity you really received.
Also called: execution · filled
Written by Javier Sánchez Ros
In plain language
A fill is the moment an order stops being an intention and becomes a position. The fill price — not the price you were watching — is what all of your math runs on.
A single order can produce several fills at different prices as it consumes multiple levels of the book. Your effective entry is the volume-weighted average of them.
Reviewing fills against intended prices is the cheapest audit in trading. Persistent gaps between the two point at order type, timing, or size problems.
Worked through
Planned at $12.00, filled at $12.09
- Planned entry
- $12.00
- Planned stop
- $11.70 (−$0.30)
- Actual fill
- $12.09
- Real risk per share
- $0.39, not $0.30
Nine cents of slippage on a twelve-dollar stock is nothing to look at. Against a 30-cent stop it is 30% more risk than the position was sized for, and the position has already been placed at the old size.
This is why the fill, not the plan, is the number that belongs in the journal. The plan describes a trade you considered; the fill describes the trade you own. Everything downstream — risk in currency, R-multiple, the ratio to the target — has to be recomputed from it or the whole record drifts.
There are two honest responses and neither is to ignore it. Trim the position so the risk matches what was intended, or accept the larger risk deliberately and write it down as such. The one that causes damage is the third: keep the size, keep the original number in the journal, and let the account run hotter than the spreadsheet believes.
Across hundreds of trades this is how a carefully designed 1% rule turns into something closer to 1.3%, without a single rule ever being consciously broken.
Why it matters
Recalculating your risk from the real fill, not the planned entry, is what keeps your actual exposure equal to the exposure you designed.
Common mistakes
- Journaling planned prices instead of fill prices, which hides the real cost of execution.
- Leaving the stop at its planned distance from a fill that came in far away from the intended entry.
Keep exploring
These concepts are connected. Understanding one usually makes the next one easier.
When only part of your order executes and the rest stays open or is canceled.
The difference between the price you expected and the price you actually got.
The price at which you open a position.
The live list of all resting buy and sell orders at each price level.
A record of every trade, including the reasoning behind it and the result.