How a fill works
A fill is the execution of your order, the moment it actually trades and you have a position. An order is just an instruction until it is filled; the fill is the real price and quantity you get. Orders can be filled in full, in part, or not at all, depending on the order type and the available liquidity, and the fill price can differ from what you saw on screen.
Worked example
You send a market buy for 10 lots. If the order book has enough resting size, you get a full fill instantly at the best available price. If only 6 lots are available at that price, you might get a partial fill of 6 and the rest at the next level, raising your average price. The difference between your intended and actual fill price is slippage.
Fills on Volity
On Volity, liquid instruments in active hours fill instantly and close to the quoted price, thanks to aggregated liquidity providers. A limit order only fills at your price or better, so it may not fill at all; a market order prioritises a fill over price. Knowing how each order type fills is the difference between getting the trade you wanted and a surprise.
Why it matters
The fill, not the chart, is where your real entry and exit prices are decided, and assuming you filled at the screen price leads to repeated small losses. Always check your actual fill and account for partials and slippage. Related: market order and slippage.
Learn more in our forex trading guide.
