When spreads are tightest
The trading day has a shape. Where liquidity concentrates, where it thins out, and how to pick a window that suits your costs.
Slippage is not spread
Two costs that get spoken about as one. Why the site measures the first and labels the second as an assumption.
In short
- Spread is the gap you cross on entry and exit. Slippage is the distance between the price you asked for and the price you got.
- Spread can be sampled from a quote. Slippage only exists after an order was sent, so it is stated as a labeled assumption and never folded into the ranked cost figures.
- Depth drives slippage, which is why the calendar and your order type matter more than the logo on the platform.
Two costs, one blurred word
Spread and slippage both make a trade cost more than the screen suggested, which is why they get spoken about as one thing. They are not. The spread is the gap between the bid and the ask at the moment you trade, and you pay it by crossing that gap. Slippage is the distance between the price you asked for and the price your order actually filled at.
The difference matters because they behave differently. The spread is visible before you commit and can be compared across firms in advance. Slippage only exists after the fact, and it depends on the size of your order and the depth available at that instant.
Why one is measured and the other is stated
Every spread figure on this site comes from a sampled quote, timestamped and stored. Slippage cannot be sampled the same way, because it is a property of an order that was actually sent, not of a quote sitting on a screen. Publishing a slippage number as if it had been measured would be an invented figure dressed as evidence.
So the site leaves it out: every cost here is the measured spread plus the commission the firm publishes, and each one says that slippage is not included. If that ever changes, it changes because there is a method behind it, and the method gets published with it.
What actually moves it
Depth is the main driver. When many providers quote in size, an ordinary order fills at or near the price you clicked. When they step back, the same order works through several price levels and fills worse. That is why the minutes around a scheduled release, the daily rollover and thin holiday sessions produce the worst fills of the week.
Order type matters too. A market order asks for whatever is available, which is exactly the moment slippage appears. A limit order refuses to fill worse than your price, and pays for that refusal with the trades it never gets into.
Budgeting for both
Treat the spread as a fixed cost you can shop for, and slippage as a variable cost you manage with timing and order type. Comparing firms on spread and commission is a decision you make once. Staying out of the worst minutes of the day is a decision you make daily.
If you trade releases deliberately, write a wider fill into the plan rather than meeting it as a surprise. If you do not, waiting a minute after the print usually returns you to ordinary pricing.
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Where to go next
Read next
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Liquidity thins at releases and session boundaries. What the widening means, what it does not, and how a rolling window keeps rankings honest.
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