# Slippage Analysis

> Slippage analysis compares your fills with benchmark prices to measure execution quality. Learn the benchmarks, the formula and how to act on results.

Source: https://learn.tradelabsai.com/orders/slippage-analysis/  
Track: Orders and Execution · Level: Advanced · Updated: 2026-10-03  
Publisher: TradeLabs AI (https://tradelabsai.com). Education, not financial advice.  
Cite as: TradeLabs Learn, "Slippage Analysis", https://learn.tradelabsai.com/orders/slippage-analysis/

Slippage analysis is the practice of measuring, over many trades, how far your actual fill prices are from the prices you intended or expected. One trade's slippage tells you little. A hundred trades tell you how much execution is really costing you, which order types and times are expensive, and whether your backtest assumptions are realistic.

## Choosing a benchmark

Slippage is always measured against a reference price. The right one depends on what you want to learn:

| Benchmark | Definition | Measures |
|---|---|---|
| Decision price | Price when you decided to trade | Total cost including hesitation |
| Arrival price | Quote when the order reached the market | Execution cost of the order itself |
| Stop or limit price | The price on your stop or limit order | Gap between plan and reality on stops |
| Midpoint at order time | Halfway between bid and ask | Spread plus slippage together |
| VWAP | Volume weighted average price over the period | Quality versus the average trader |

For most individual traders, arrival price for market orders and stop price for stop orders are the most useful.

## The calculation

```
Slippage (buy) = Fill price − Benchmark price
Slippage (sell) = Benchmark price − Fill price
```

Positive values are costs; negative values are improvements. Express slippage in a common unit so you can compare trades: basis points (hundredths of a percent), ticks, or R multiples of your planned risk.

**Example: Slippage in R**
Your plan risks $1.50 per share, so 1R = $1.50. Your stop at $48.50 fills at $48.32, 18 cents of slippage. In R that is 0.12R. If your stops slip 0.12R on average, every planned 1R loss is really 1.12R, which lowers your [Expectancy](https://learn.tradelabsai.com/risk/expectancy/) and should be reflected in your sizing.

## A simple spreadsheet method

Add these columns to your [Trading Journal](https://learn.tradelabsai.com/start-here/trading-journal/):

1. Order type (market, limit, stop).
2. Benchmark price (quote at send, or stop price).
3. Fill price and quantity.
4. Slippage in dollars, basis points and R.
5. Time of day and market conditions (normal, news, open, close).

After 50 to 100 trades, group the results.

| Grouping | What you might find |
|---|---|
| By order type | Stops slip more than limits; market orders slip more at the open |
| By time | First five minutes far more expensive than midday |
| By instrument | Thin stocks or far dated options cost much more |
| By size | Larger orders slip more, a sign of market impact |
| By conditions | News releases dominate the worst slippage |

## Acting on the results

- **High stop slippage:** consider wider but fewer trades, smaller size through events, or guaranteed stops where available.
- **High market order slippage at the open:** wait a few minutes or use marketable limit orders.
- **Large slippage on bigger orders:** split orders or use execution algorithms. See [Market Impact](https://learn.tradelabsai.com/orders/market-impact/) and [VWAP, TWAP and POV Execution](https://learn.tradelabsai.com/orders/vwap-twap-and-pov-execution/).
- **Instrument specific costs:** remove the most expensive instruments from your list.

## Update your backtests

If your live slippage averages 2 ticks per trade but your backtest assumed 0.5, your backtest overstates performance. Feed measured slippage back into testing. See [Costs and Slippage in Backtests](https://learn.tradelabsai.com/research/costs-and-slippage-in-backtests/).

## Professional slippage analysis

Institutions run transaction cost analysis (TCA) on every order, comparing results with arrival price, VWAP and implementation shortfall, and breaking costs into delay, impact and spread. The principles are the same as the spreadsheet method above, just with more data. See [Implementation Shortfall](https://learn.tradelabsai.com/orders/implementation-shortfall/) and [Best Execution and Execution Quality](https://learn.tradelabsai.com/orders/best-execution/).

## Frequently asked questions

### How do you calculate slippage?

For a buy, subtract the benchmark price from the fill price; for a sell, subtract the fill price from the benchmark. Positive results are costs.

### What is acceptable slippage?

It depends on the market and strategy. Compare it with your average profit per trade; if slippage takes a large share of it, your strategy is fragile.

### Why should I measure slippage in R?

Because it shows directly how execution changes your planned risk and reward, regardless of price level or instrument.

## Continue learning

- Next lesson: [Market Impact](https://learn.tradelabsai.com/orders/market-impact/)
- Previous lesson: [Transaction Costs](https://learn.tradelabsai.com/orders/transaction-costs/)
- Related: [Transaction Costs](https://learn.tradelabsai.com/orders/transaction-costs/): Transaction costs include commissions, spreads, slippage, market impact and missed trades. Learn each part, how to estimate it and why it decides profits.
- Related: [Slippage](https://learn.tradelabsai.com/markets/slippage/): Slippage is the gap between the price you expect and the price you get. Learn what causes it, how to measure it and the practical ways to reduce slippage.
- Related: [Implementation Shortfall](https://learn.tradelabsai.com/orders/implementation-shortfall/): Implementation shortfall compares a paper portfolio traded at the decision price with what you actually achieved. Learn the formula and its parts.
- Related: [Best Execution and Execution Quality](https://learn.tradelabsai.com/orders/best-execution/): Best execution is a broker's duty to get you the most favourable terms on orders. Learn what it covers, price improvement, routing reports and how to judge fills.
- Related: [Trading Journal](https://learn.tradelabsai.com/start-here/trading-journal/): A trading journal records every trade so you can find what works and what keeps costing you. Learn what to log, a template and how to review it.
- Related: [Costs and Slippage in Backtests](https://learn.tradelabsai.com/research/costs-and-slippage-in-backtests/): Ignoring costs is the fastest way to fool yourself in a backtest. Learn the costs to include, how to estimate slippage and market impact, and conservative rules.