Slippage
An exchange holds orders stacked in layers at each price — 'I'll sell at this price,' 'I'll buy at this price.' That stack is the order book. When you send a market order — 'buy it right now' — the exchange fills you by working through the sell orders sitting there at that moment, cheapest first.
The trouble starts when the amount stacked at one price is smaller than your order. Say Bitcoin shows $100,000 but only 0.5 BTC is offered at that price. The moment you market-buy 1 BTC, the remaining 0.5 BTC fills against the next-cheapest offer — say $100,050. Your average entry ends up above the $100,000 you saw on screen. That gap is slippage.
The moments when slippage blows up are fairly predictable: big news hits and price moves violently; leveraged positions get liquidated in a cascade and the book empties in seconds; quiet hours when trading is thin; and coins with low volume to begin with. The bigger your order, the more price levels it has to dig through, so slippage grows too.
A limit order guarantees you'll never fill worse than the price you set. The catch: if price passes by without touching your order, you may not get filled at all. Market orders buy certainty of execution by giving up price; limit orders protect price by giving up certainty of execution. Neither comes free.
0.05% per trade sounds like nothing, but trade often and it stacks up right alongside fees. If your strategy's edge is thin to begin with, slippage plus fees alone can flip a plus into a minus. Trading costs aren't something to 'think about later' — they belong in the math from the start.
What the data actually shows
Slippage is a trading cost, not a chart signal, so it doesn't appear directly in Barobara's win-rate statistics. But keep this one thing in mind: the historical win rates of the chart signals Barobara publishes mostly sit near 50% — almost a coin flip. Even where an edge exists, it's razor thin — and slippage and fees eat exactly that thin edge. It's one reason real results come out a bit worse than the statistics pages suggest. Exchange fees and ways to reduce them are on the fee comparison page; each signal's historical record is in the setup statistics.
Common misconceptions
"Slippage means the exchange is playing games?" Mostly no. When the order book is thin, your order works through several price levels to fill — a natural feature of market structure. That said, if your fills are consistently and abnormally bad, questioning that exchange's liquidity or quality is fair.
"Just use limit orders and you can never lose out?" Limit orders have no slippage but may never fill. If price runs off without touching your order, you pay the cost of missing the move entirely. You're swapping slippage for non-execution risk — there's no free lunch.
FAQ
Q. How big is slippage usually?
For small orders on a heavily traded market like Bitcoin, usually under 0.01–0.1%. But in violent moves or on thinly traded coins it can top 1%. There's no fixed number — it depends on how much is sitting in the order book at that moment.
Q. Is there a way to reduce slippage?
The basics: use limit orders, avoid moments of violent movement like right after big news or during liquidation cascades, and split large orders into pieces. It can't be eliminated entirely, and limit orders take on the risk of not filling instead.