Every trade has a cost beyond a broker's commission, and most beginners never see it clearly because it isn't billed separately — it's baked into the price itself. Spread and slippage are the two costs that quietly work against your edge, and understanding both is part of risk management, not an afterthought to it.
The Spread: A Cost on Every Trade
Every currency pair quotes two prices at once:
- Bid — the price you sell at.
- Ask — the (higher) price you buy at.
The gap between them is the spread, and it's how many brokers make money on "commission-free" accounts. The moment you open a trade, you start slightly underwater by the size of the spread — a EUR/USD position with a 2-pip spread needs price to move 2 pips in your favor just to reach breakeven.
Spread size isn't fixed. It depends on:
- The pair — majors like EUR/USD typically have tight spreads (often under 1-2 pips with a good broker); exotic pairs can run 20-50+ pips.
- Liquidity and time of day — spreads widen outside the main trading sessions, and can spike sharply right around high-impact news.
- Account type — covered in its own section below, since it's a common source of confusion.
A spread that looks small in pips is not automatically small in cost — check it against the Pip Calculator for your actual position size before assuming it's negligible.
Slippage: A Cost on Fast Moves
Slippage is different — it's the gap between the price you requested and the price your order actually filled at, and it only shows up when the market moves faster than your order can be executed. You click "Buy" at one price; by the time the broker's server processes it, the market has already moved, and you're filled at whatever price is available at that instant.
Slippage happens most often around:
- High-impact news releases, where price can gap several pips in a fraction of a second — the exact moments covered in the Economic Calendar.
- Low-liquidity periods, like the transition between the New York close and the Asian session open, where there simply isn't enough volume at nearby prices to fill an order without moving it.
- Stop Loss and Market orders during a gap — a Stop order guarantees an exit, not a price; in a fast market it can fill well past the level you set. Limit orders don't have this problem, but they can simply fail to fill at all if price never returns.
Slippage can also work in your favor (positive slippage, a better fill than requested) — brokers aren't obligated to only slip you the wrong way, but the unfavorable direction is the one that costs traders money and gets remembered.
A Worked Example: Total Cost of a Trade
Say you open 1 standard lot (100,000 units) of EUR/USD, where pip value is roughly $10. The broker quotes a 1.5-pip spread, so you're already down about $15 the instant the trade opens, before price has moved at all. Ten minutes later, a surprise headline hits and you decide to exit with a Market order — but liquidity is thin for a second and your close fills 1.2 pips worse than the price you saw on screen, an extra $12 of slippage. Total cost of that single round trip: roughly $27, none of it a commission line item, all of it invisible unless you compare your requested price and fill price directly. Run the numbers for your own position size with the Pip Calculator — a cost that looks trivial in pips often isn't trivial in dollars once it's scaled to a real lot size.
ECN/Raw vs Standard Accounts: Same Cost, Different Label
Brokers commonly offer two account structures, and it's easy to assume one is "cheaper" without actually comparing totals:
- Standard / "commission-free" accounts — wider, often fixed spreads, no separate commission. The spread cost is bundled into the price you see.
- ECN / Raw / STP accounts — much tighter, more variable spreads (sometimes near 0 on majors during peak liquidity) plus a separate fixed commission per lot, charged whether the trade wins or loses.
Add the commission to the raw spread on an ECN account and compare that total to a standard account's all-in spread for the same pair and time of day — that's the only fair comparison. ECN accounts also tend to report slippage more transparently (since execution is passed through to the underlying liquidity provider rather than filled internally by the broker), which is worth factoring in separately from the raw cost number.
Why This Matters for Your Strategy
Both costs are usually small individually, but they compound: a strategy that takes many trades a day is far more sensitive to spread cost than one that takes a few trades a week, and a strategy that relies on Stop orders during news is far more exposed to slippage than one that avoids trading through high-impact releases. When you backtest or evaluate a strategy's win rate, build in an estimate for both — a system that's only profitable assuming zero spread and zero slippage isn't actually profitable.
A Word of Caution
Neither cost is something you can eliminate, only manage. Compare spreads across brokers for the pairs you actually trade (see our recommended brokers), avoid holding positions through major news releases if you're not deliberately trading the news, and size stops with real volatility in mind using a tool like ATR rather than a fixed pip count that a routine spike could slip straight through.