Max deviation is a setting that hides slippage cost
Posted: Sat Oct 31, 2026 7:39 am
That small field in the order window labelled deviation, or slippage in points, is a permission slip. Set it to 20 points on a five-digit broker and the platform is allowed to fill the order up to 2 pips away from the clicked price without asking. Most EAs ship with a default of 10, 30 or even 50, left untouched for years.
The trouble is that it feels like protection and works like a licence. A wide setting makes rejects and requotes vanish, which looks like better execution, but what actually happened is that the rejects got converted into worse fills. On a 3 pip scalp, a default of 3 pips of allowed deviation can eat the whole target.
A reasonable approach is to set deviation to a fraction of the target, say 5 to 10 percent, and then track how often orders fail. A few failed orders is the price of not paying for bad fills. Whether that is acceptable depends on the strategy: a mean-reversion scalp can usually afford to miss a trade, a breakout scalp that needs the fill may not.
Also remember some platforms read the value in points and some in pips, and some brokers ignore it completely for market execution. Check on a demo or a micro lot before trusting it.
Does your broker honour the deviation value at all, and how was that confirmed?
The trouble is that it feels like protection and works like a licence. A wide setting makes rejects and requotes vanish, which looks like better execution, but what actually happened is that the rejects got converted into worse fills. On a 3 pip scalp, a default of 3 pips of allowed deviation can eat the whole target.
A reasonable approach is to set deviation to a fraction of the target, say 5 to 10 percent, and then track how often orders fail. A few failed orders is the price of not paying for bad fills. Whether that is acceptable depends on the strategy: a mean-reversion scalp can usually afford to miss a trade, a breakout scalp that needs the fill may not.
Also remember some platforms read the value in points and some in pips, and some brokers ignore it completely for market execution. Check on a demo or a micro lot before trusting it.
Does your broker honour the deviation value at all, and how was that confirmed?