TRADRILL / GUIDE / GETTING STARTED
What Is Slippage in Trading? Why Your Order Fills at a Different Price
Written by DUOCODE TECHNOLOGYPublished and reviewed 8 min read
Slippage is the difference between the price you expected when you sent an order and the price at which it actually filled. You click to buy at one number and the confirmation shows another—usually because the market moved in the fraction of a second between your click and the execution. It is one of the most common surprises new traders meet, and it is not a glitch: it is how live markets work when prices are moving and orders take real time to reach the market.[3]
This guide explains what slippage is, why it happens, how it differs from the bid-ask spread, how it can make a stop-loss fill worse than its trigger, and practical ways to reduce it. Slippage cannot be removed entirely, but you can understand and limit it. Before it costs you real money, watch how your fills and stops behave with virtual funds—Tradrill is built for exactly that kind of low-stakes rehearsal, with results that are simulated rather than real trades.[1] [4]
Short answer
- Slippage is the gap between your expected price and your actual fill price.
- It grows when markets are fast, volatile, gapping, or thinly traded—especially with market orders.
- A limit order caps the price you'll accept, but it may not fill at all; practise how fills behave before risking real money.
What slippage is and why it happens
When you send a market order, you are asking to trade at the best price available right now—but 'right now' is a moving target. FINRA notes that during volatile or fast-moving markets the price you see quoted may not be the price you get, because quotes and executions can lag when volume is high. In the time it takes your order to travel and match against a counterparty, the price can shift, and your fill lands a little (or a lot) away from what you expected. That gap is slippage.[3]
Slippage can go either way. Sometimes the price moves in your favour and you fill better than expected—positive slippage. More often it is remembered because it hurt: the price moved against you between click and fill. The size of the gap depends on how fast the market is moving and how much liquidity sits at the price you wanted. The thinner the market and the faster the move, the wider the slippage tends to be.[3]
- Slippage = actual fill price minus the price you expected.
- It appears mostly with market orders, which prioritise speed over price.
- Fast, volatile, or gapping markets widen it; calm, liquid markets narrow it.
- It can be negative (worse) or positive (better) than expected.
Slippage vs the bid-ask spread
Slippage is easy to confuse with the bid-ask spread, but they are different costs. The spread is the standing gap between the highest price buyers will pay (the bid) and the lowest price sellers will accept (the ask) at a single moment. It is known before you trade: buy at the ask, sell at the bid, and the difference is a cost you can see in advance. Slippage, by contrast, is the extra movement that happens because the market shifts—or your order is large enough to eat through several price levels—between the moment you decide and the moment you fill.[1]
Think of it this way: the spread is the toll posted at the gate, while slippage is how far the gate moves while you are walking through it. In a calm, heavily traded market both are small. In a thin or fast market, the spread widens and slippage grows on top of it, so your true cost of getting in or out can be noticeably larger than the quote suggested.[3]
| Cause of slippage | Why it happens | What helps |
|---|---|---|
| High volatility | Prices move quickly between your click and the fill | Use limit orders; avoid trading into sharp swings |
| Low liquidity / thin market | Few resting orders, so your trade moves the price | Trade liquid instruments; size positions sensibly |
| Price gaps (news, open, weekend) | Price jumps with no trading in between | Expect gaps around events; avoid holding into known news |
| Market orders | They prioritise speed over price and take whatever is available | Use a limit order when price matters more than certainty of filling |
| Large order size | Your order eats through several price levels | Break up size; check available depth first |
The spread is a cost you can see before you trade. Slippage is the extra movement between your decision and your fill—it grows in fast, thin markets.
How slippage affects stop-loss orders
Slippage matters most where it surprises people: on stop-loss orders. Investor.gov explains that a stop order becomes a market order once the stop price is reached—and a market order does not guarantee a price, only that it will execute. So your stop is a trigger, not a promise. In a fast or gapping market the fill can land well below (for a sell stop) the level you set, because by the time the order becomes live the price has already moved past it.[1]
This is why a stop is a risk-control tool, not a guarantee of your exact exit. The SEC warns that day trading can be extremely risky, and fast markets are exactly where slippage on stops is worst. A stop-limit order can cap how bad a fill you'll accept, but it carries the opposite risk: if price blows straight past your limit, the order may not fill at all and you stay in the trade. Neither choice removes risk—each trades one downside for another, which is worth rehearsing before real money is on the line.[2] [1]
Know your order type
A market order fills fast but at any available price; a limit order caps your price but may not fill. Choose deliberately.
Treat stops as triggers, not guarantees
A stop becomes a market order when hit, so in fast markets it can fill worse than the stop price you set.
Avoid the worst moments
Slippage widens around news, market opens, and in thinly traded instruments—size and time your trades with that in mind.
Rehearse how fills behave
Watch how orders and stops actually fill with virtual funds before you rely on them with real money.
Before you place your next order
Use this checklist to keep slippage from surprising you.
- I know the difference between a market order (speed) and a limit order (price control).
- I understand a stop can fill worse than its trigger in a fast market.
- I check liquidity and avoid trading into sharp, thin, or news-driven moves.
- I size my orders so I don't move the price against myself.
- I have practised how my fills and stops behave with virtual funds first.
Frequently asked questions
- What is slippage in trading?
- Slippage is the difference between the price you expected when you sent an order and the price at which it actually filled. It usually happens because the market moved in the moment between your click and the execution—FINRA notes that in fast-moving markets the quoted price may not be the price you get.
- Why did my order fill at a different price?
- Most likely because you used a market order in a moving or thinly traded market. A market order takes the best price available at the instant it executes, and that price can shift between your click and the fill. Volatility, price gaps, low liquidity, and large order size all widen the gap.
- How is slippage different from the spread?
- The bid-ask spread is the known gap between the buy and sell price at a single moment—you can see it before trading. Slippage is the extra movement that happens because the market shifts, or your order is large enough to move it, between your decision and your fill. In fast, thin markets both grow.
- How can I reduce slippage?
- Use limit orders when price matters more than certainty of filling, trade liquid instruments, avoid volatile or news-driven moments, and size positions sensibly so you don't move the price yourself. Remember a stop-loss becomes a market order when triggered, so it can still fill worse than your stop price.
Related guides
- TRADRILL / GUIDE / GETTING STARTEDOrder Types Explained: Market, Limit, Stop and Stop-LimitThe order you choose decides how—and whether—your trade fills. Learn how market, limit, stop and stop-limit orders work, when to use each and their trade-offs.
- TRADRILL / GUIDE / RISK MANAGEMENTWhat Is a Stop-Loss Order and How to Set OneA stop-loss is a resting order that triggers once price reaches a set level, used to cap a loss. Learn how to set one, and how stop and stop-limit orders differ.
- TRADRILL / GUIDE / TRADING BASICSDay Trading for Beginners: A Realistic Starter GuideA realistic beginner's guide to day trading: what it is, the risks regulators warn about, the rules that apply, and how to start with risk-free practice first.
- TRADRILL / GUIDE / TRADING DISCIPLINE7 Common Trading Mistakes Beginners Make (and How to Avoid Them)The most common beginner trading mistakes—no plan, overtrading, revenge trading, ignoring risk, misusing leverage—and practical, non-hype ways to avoid each.
Sources and further reading
Authoritative sources consulted for how orders fill, stops behave and prices move in this guide. Accessed 5 August 2026.
- [1]U.S. SEC — Investor.gov: Types of Orders (market, limit, stop-loss)
- [2]U.S. SEC — Investor.gov: Thinking of Day Trading? Know the Risks. (Director's Take)
- [3]FINRA: Questions About Online Trading
- [4]U.S. Commodity Futures Trading Commission: CFTC Letter No. 01-60 — Rule 4.41 hypothetical-performance disclosures
Understand slippage before it costs you
Slippage is a normal part of live markets, not a broker trick—but it is a real cost you can manage with the right order type, timing, and size. Tradrill lets you watch how fills and stops behave with virtual funds and review your habits—no trade signals, no auto-trading, and no promise that a practice result will repeat live.
Educational information only. Tradrill provides no trading signals, no auto-trading and no financial advice. Trading involves risk; simulated results are hypothetical and not a promise of future or live performance.