Slippage in Trading: What It Is and How to Reduce It

Slippage in trading is the difference between the price you expected to get on an order and the price at which the order actually filled. It happens because markets move between the moment you send an order and the moment it executes, and because there is not always enough volume waiting at your price. Slippage is a real trading cost, and it belongs inside your risk management in trading plan just like spread, commission and stop placement.

Quick answer: Slippage in trading is the gap between the expected price of an order and the price at which the order is actually filled. Negative slippage means a worse fill, positive slippage means a better fill. Slippage is largest in fast or thin markets, around news releases, on large orders and on market or stop orders.

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What is slippage in trading?

Slippage is the difference between the price a trader intended to trade at and the price the trade was actually executed at. If you click buy when the screen shows 100.00 and your fill comes back at 100.05, you experienced 0.05 of slippage.

An order is a request, not a guarantee. A market order takes the best price available at that instant, whatever it is, and a stop order becomes a market order once triggered, so both can slip.

The key facts in one place:

What is the difference between positive and negative slippage?

Negative slippage is a fill at a worse price than expected, and positive slippage is a fill at a better price than expected. Slippage is simply price movement during execution, so it can go either way.

• Negative slippage: you expect to buy at 100.00 and pay 100.10, or expect to sell at 100.00 and receive 99.90.
• Positive slippage: you expect to buy at 100.00 and pay 99.95, or expect to sell at 100.00 and receive 100.05.

In practice, stops and market orders in fast markets tend to fill against the trader. A buy stop is triggered because price is rising, so the fill is usually above the stop level. That is why a careful plan assumes some negative slippage on stops.

A limit order gives the opposite trade-off: a buy limit at 100.00 fills at 100.00 or lower, never higher, but it may never fill. The guide on market order vs limit order covers that choice.

Worked example: how much does slippage cost?

The chart below shows a buy stop order placed at 100.00 above a quiet range. A news candle pushes price straight through the stop. By the time the order executes, the best available offer is 100.40, so the trade fills 0.40 above the intended price.

Now put a position size on it. Suppose the plan was:

1. Buy 500 units on a stop at 100.00.
2. Place the stop-loss at 98.00, a 2.00 risk per unit.
3. Target 104.00, a 4.00 reward per unit (a 2 to 1 reward-to-risk ratio).

The planned numbers are:

• Planned risk: 2.00 × 500 = 1,000 USD
• Planned reward: 4.00 × 500 = 2,000 USD

The actual fill at 100.40 changes everything:

• Slippage cost on entry: 0.40 × 500 = 200 USD
• Real risk to the 98.00 stop: (100.40 minus 98.00) × 500 = 2.40 × 500 = 1,200 USD
• Real reward to the 104.00 target: (104.00 minus 100.40) × 500 = 3.60 × 500 = 1,800 USD
• Real reward-to-risk: 1,800 ÷ 1,200 = 1.5 to 1, down from 2 to 1

One fill turned a 1,000 dollar risk into 1,200 dollars, a 20% increase. If the stop also slips on the way out (filling at 97.80 instead of 98.00), the loss grows to 2.60 × 500 = 1,300 USD. This is why the risk-reward ratio you plan on paper is rarely the one you get in fast markets.

What causes slippage?

Slippage is caused by price moving, or by liquidity disappearing, between the moment an order is sent and the moment it is filled. Six causes account for almost all of it.

Volatility

Fast markets cause slippage because the quote on screen can be stale by the time your order arrives. The ATR indicator gives a rough sense of how fast a market is moving.

News releases

Scheduled economic data is the most reliable source of slippage. Around a release, liquidity providers often pull quotes, spreads widen and price can jump several levels at once. The NFP trading guide shows how the US jobs report moves markets within seconds, the environment the chart above illustrates.

Thin liquidity

Liquidity is the volume resting in the order book near the current price. In thin markets (small-cap stocks, minor crypto tokens, exotic pairs, or major markets outside their main sessions) even a normal order can move through several price levels.

Order size

Large orders slip more because they consume more of the order book. If 200 units are offered at 100.00 and you buy 1,000 at market, the other 800 fill at 100.01, 100.02 and higher. This is called price impact.

Price gaps

A gap is a jump in price with no trading in between, often after a weekend or an earnings announcement. A stop inside the gap fills at the first available price on the other side.

Latency

Latency is the delay between your decision and the order reaching the market. A slow connection or a manual click during a fast move gives price room to change.

Slippage vs spread: what is the difference?

The spread is the difference between the bid and ask prices quoted before you trade, and slippage is the difference between your expected price and your actual fill after you trade. The spread is visible in advance. Slippage is only known once the order has executed.

Both are costs, and they add together. The chart below shows what the spread alone costs on one standard lot of EURUSD, where one pip is worth 10 US dollars.

A 1 pip spread costs 10 USD per standard lot. If the same trade also suffers 0.5 pips of negative slippage on entry, that adds another 5 USD, for a total of 15 USD before commission. Around news, spreads widen and slippage grows at the same time, so the two costs tend to spike together.

What is slippage tolerance in crypto?

Slippage tolerance is a setting on decentralised exchanges (DEXs) that sets the maximum price change a trader will accept on a swap before the transaction is cancelled. If you set 0.5% tolerance and the price moves more than 0.5% before your transaction is confirmed on the blockchain, the swap fails instead of filling at a worse price.

On a DEX, slippage comes from other transactions changing the pool price before yours confirms, and from the size of your swap relative to pool liquidity. A tolerance set too low causes failed transactions that can still cost network fees. A tolerance set too high allows a much worse fill and can attract bots that front-run large pending swaps.

How can you reduce slippage?

You can reduce slippage by choosing the right order type, avoiding the most volatile seconds, trading when liquidity is deepest and sizing orders for the market.

1. Use limit orders for entries where you can. A limit order cannot fill at a worse price than your limit. Gianluca Pizzituti, Velotrade's co-founder, is direct about his own approach to entries: "Always limit orders. Always." The trade-off is that some limit orders will never fill.
2. Consider a stop-limit order for breakout entries. A stop-limit order triggers like a stop but only fills up to a limit price, which caps slippage at the cost of possibly missing the move. Brokers that offer it make this a useful tool; on Velotrade, stop-limit orders are disabled, so use a limit order placed after the breakout instead.
3. Avoid the seconds around major releases. Check the economic calendar and avoid new market orders around high-impact data unless news trading is your deliberate strategy.
4. Trade during the most liquid hours. Major forex pairs are most liquid when London and New York overlap; US stocks and index ETFs during regular US hours.
5. Size orders for the market's liquidity. In thin markets, smaller orders move the price less.
6. Build slippage into your risk. Use the position size calculator for the base size, then widen the risk per unit by your average slippage.
7. Avoid holding through known gaps, such as earnings on single stocks, if a gapped stop would break your plan.

How do you measure slippage in a trading journal?

You measure slippage by recording the intended price and the actual fill price for every entry and exit, then calculating the difference. A trading journal is the natural place to do it.

1. Add two columns for each order: intended price and fill price.
2. Calculate slippage per order: for buys, fill minus intended; for sells, intended minus fill. A positive number is a worse fill.
3. Multiply by position size to get slippage in currency.
4. Divide by your planned risk per unit to express slippage as a fraction of R (one unit of planned risk). In the worked example, 0.40 ÷ 2.00 = 0.2R.
5. Tag each trade with order type, session and whether news was due within a few minutes.
6. Review averages monthly to see which order types and sessions carry your hidden costs.

Adding your measured average slippage to a backtest also makes it more honest, because perfect fills overstate results.

How does slippage work in a prop firm evaluation?

Slippage affects a prop firm evaluation in the same way it affects any account: a worse fill uses more of your loss limits than you planned. At Velotrade, a multi-asset prop trading firm offering simulated evaluations, the hard limits are the daily loss limit and the static maximum drawdown. The daily loss limit resets at 00:30 UTC and is set from the higher of balance or equity (5% on CLASSIC 2-Step, 4% on CLASSIC 1-Step, 3% on PRO 1-Step).

There is no per-trade risk cap and stop-losses are not required, so slippage management is up to the trader. If the 5% daily limit works out to 5,000 USD, three losses planned at 1,000 USD each leave 2,000 USD of room. If each stop slips by 20% as in the worked example, the losses total 3,600 USD and the room shrinks to 1,400 USD. News trading is allowed, which makes this arithmetic more important. Read static maximum drawdown explained to see how the drawdown floor works.

What are common slippage mistakes?

The most common mistake is ignoring slippage when planning risk. Others include tight stops right before news, market orders in thin markets, judging strategies on perfect backtest fills (small-target styles in the scalping trading guide are especially sensitive), and overtrading, since every trade pays the spread and risks slippage. Broker disclosures and academic studies consistently find that most retail day traders lose money, and trading costs are part of that picture.

Can AI help reduce slippage?

AI tools can help analyse slippage, but they do not remove it. A model can sort a trade log by session, order type and news proximity to show where fills are worst. The guides on AI trading strategies and backtesting trading strategies explain how to test such ideas properly.

No software can guarantee a fill price on a market or stop order, and decisions about order type, timing and size still need human judgement.