Why Did My Crypto Market Order Fill at a Worse Price Than I Saw?
Direct answer
Crypto slippage in brief
Your market order filled at a worse price because a market order buys or sells at the best prices available at that moment, not at the last price you saw. If the order is bigger than the quantity resting at the best price, it eats through the next price levels in the order book, and in a fast market the book can move between your click and the fill. Coinbase defines slippage as the difference between the expected price of a trade and the price at which it is executed. You limit it with limit orders, smaller orders, liquid pairs, and a slippage tolerance on decentralised exchanges.
- Market order = execution first, price second (Investor.gov)
- Slippage = expected price minus executed price (Coinbase)
- Big orders walk the order book through several price levels
- Thin pairs and news spikes widen it
- Limit orders cap the price but may not fill
You clicked buy at $100, and the confirmation says $100.40. Nothing was broken: that gap is slippage, and on a crypto exchange it comes mainly from how a market order meets the order book.
What people on X are asking
In September 2026 one account put it bluntly: "Getting filled and getting your price are not the same goal", explaining that a market order puts execution first and that "in volatile market you may pay way more than you saw". A crypto glossary post from June 2025 said a market order "fills instantly at the best available price" but warned you "may pay more due to slippage", and a July 2025 thread called order types the "defense against crypto slippage". All three are right. Here is what actually happens.
What people in the thread said
- @EClock24, replying in the same thread, summed up the rule of thumb: in high volatility with a thin order book, use a limit order or expect slippage. That matches the cause list above.
- @EClock24 added that on thin altcoins an extra 2% paid by a market order is effectively the fee for not waiting. Whether it is 2% depends on the book depth at that moment; check the order book before sizing.
These are community comments, summarised in our words; the data and sources below come first.
The fact-checked answer
A market order promises a fill, not a price. The SEC's Investor.gov defines a market order as an order to buy or sell at the current market price; as long as there are willing buyers and sellers you are almost always guaranteed execution, but the price you pay "may not be the price you expected". Crypto exchanges work the same way. Coinbase describes slippage as the difference between the expected price of a trade and the executed price, says it can be positive or negative, and names market volatility and low liquidity as the main causes.
Walking the order book. The "price" on screen is usually the last trade or the best bid/ask. Behind it are sell orders stacked at higher prices. A market buy takes the cheapest first, then the next, until it is full. This example uses an invented order book to show the arithmetic:
How a 3 BTC market buy walks a thin order book (illustrative)
Hypothetical book for illustration only, not live exchange data. Average fill = $225,303 ÷ 3 = $75,101, which is $101 (0.13%) above the $75,000 best ask the screen showed. Fees are charged on top. Tap a column header to sort.
| Best ask | $75,000 | 1.0 BTC | 1.0 BTC | $75,000 |
| Level 2 | $75,060 | 0.8 BTC | 0.8 BTC | $60,048 |
| Level 3 | $75,150 | 0.7 BTC | 0.7 BTC | $52,605 |
| Level 4 | $75,300 | 2.0 BTC | 0.5 BTC | $37,650 |
| Total | – | – | 3.0 BTC | $225,303 |
On a liquid pair the book is deep and a small order fills at the best price. On a small-cap token, a few thousand dollars can move through several levels, and slippage of several percent is possible.
Why fast markets make it worse. Between the moment you see a price and the moment the exchange processes your order, other orders arrive and cancel. Around big news or liquidation cascades, market makers pull quotes, the book thins and the spread widens, so the same order fills further away. The same applies to stop orders: Investor.gov notes that when the stop price is reached the stop becomes a market order, so a stop in a falling market can fill well below the stop price.
Fees are not slippage, but they add up. Slippage is the price difference; fees come on top. Fee schedules vary by venue and product; Kraken's published fee schedule, for example, shows a 0.25% fee on the notional value both to open and to close a perpetual futures position. A 0.13% slippage plus 0.25% in each direction is a real cost on a short-term trade.
On a decentralised exchange. A DEX automated market maker prices from a formula based on the pool's reserves, so a larger trade moves the price more (price impact). Wallets let you set a slippage tolerance: if the executed price would be worse than that percentage, the transaction fails instead of filling. Setting the tolerance very high to "make it go through" invites a bad fill.
Free PDF
Crypto order pre-trade checklist (PDF)
Run through this before a market order on any exchange.
The pair
The order
- Is my size less than the quantity near the best price? If not, split it or use a limit order
- Is there news, a funding reset or a big liquidation in progress? If yes, wait or use a limit
- Limit price set at the worst price I am willing to pay
- On a DEX: slippage tolerance set low, not left at a high default
After the fill
Fill-in fields in the PDF: Pair, exchange and order size in coins and dollars; Best bid, best ask and spread (ask − bid) right now; Quantity resting within 0.5% of the best price; Expected price, average fill price, slippage in % and fees in $.
Download the PDF (44 KB, made by UXS, no sign-up)
Slippage depends on how thin the book is; see how to read bids, asks and depth in a crypto order book.
Decision helper
| Situation | Use |
|---|---|
| Liquid pair, small size, calm market | Market order is usually fine |
| Thin token or size bigger than the top of book | Limit order, or split the order |
| Breaking news, high volatility | Limit order or wait |
| Must exit now whatever the price | Market order, accepting slippage |
| DEX swap | Low slippage tolerance; check price impact |
For the basic order types in stocks, see market order vs limit order; for leveraged crypto positions where fast fills matter most, read what a liquidation in crypto futures is and how much leverage is too much for a beginner.
Common mistakes
- Using market orders on low-liquidity tokens.
- Treating the last traded price as the price you will get.
- Placing tight stops that become market orders in a gap.
- Setting a high DEX slippage tolerance just to get the swap through.
- Ignoring fees when judging a fill.
FAQ
What is slippage in crypto?
The difference between the price you expected and the price your trade executed at.
Why is slippage worse on small coins?
Their order books are thinner, so an order eats through more price levels.
Can slippage be positive?
Yes. If the price moves in your favour before the fill, you can get a better price.
Does a limit order stop slippage?
It caps the price you pay or receive, but the order may not fill at all.
What slippage tolerance should I use on a DEX?
As low as lets the trade execute in normal conditions; higher tolerance means you accept a worse price.
Are stop-loss orders affected by slippage?
Yes. A triggered stop becomes a market order and can fill below the stop price in a fast market.
Sources
- Investor.gov: Market order
- Investor.gov: Stop order
- Coinbase Learn: What is slippage in crypto
- Kraken: Fee schedule
Facts checked November 10, 2026. X posts are cited as evidence of the question, not of the answer.