Understanding Trading Costs: Spreads, Commissions and Swaps

The advertised spread on a broker’s homepage is rarely the full story of what a trade actually costs you. Real trading cost is a combination of the spread, any commission, and — for positions held overnight — swap charges. Understanding how these three combine, and how to calculate them for your own position size, is essential for comparing brokers honestly and for judging whether a strategy is actually profitable after costs.

The spread: the cost built into every trade

The spread is the difference between the bid price (what you can sell at) and the ask price (what you can buy at). It’s quoted in pips — or fractions of a pip, called pipettes — and it’s paid automatically the moment you open a trade, since you enter at the ask price and your position is immediately valued at the (lower) bid price.

Spreads come in two forms:

• A fixed spread stays the same regardless of market conditions — predictable, but often wider on average.
• A variable spread (also called floating) moves with real-time market liquidity — often tighter during active hours, but can widen sharply during news events or thin liquidity (such as around rollover or major holidays).

Worked example: on a standard lot (100,000 units) of EUR/USD with a 1.0-pip spread, the cost of simply opening and immediately closing the position is roughly $10 (1 pip ≈ $10 per standard lot on EUR/USD, since the pip value depends on lot size and the currency pair).

Commission: the explicit, separate fee

Some accounts — particularly ECN/raw-spread accounts — charge a commission per lot traded (per side, or “round turn,” covering both opening and closing) in exchange for offering much tighter spreads, sometimes near zero on major pairs. A typical structure might be a set dollar amount per standard lot round turn, though exact figures vary by broker and account type — always check the specific published rate rather than assuming a figure.

Worked example: a 0.1-pip spread (≈$1 on a standard lot) plus a $7 round-turn commission costs about $8 total — potentially cheaper than a 1.0-pip no-commission spread (≈$10), depending on the exact numbers. This is why comparing spread alone, without accounting for commission, gives an incomplete picture. See ECN vs. market maker brokers for how these account types typically differ in pricing structure.

Swap: the cost (or credit) of holding overnight

Swap — also called overnight financing or rollover — is charged (or occasionally credited) when you hold a position open past the broker’s daily rollover cutoff, commonly around 5pm New York time, though the exact time and any weekend triple-swap convention varies by broker. Swap reflects the interest rate differential between the two currencies in the pair, roughly following the logic of a carry trade: holding the higher-yielding currency long against a lower-yielding one may generate a credit, and vice versa, though broker markups mean the actual swap rate charged is rarely identical to the pure interest rate differential.

Swap doesn’t apply if you close a trade within the same day, before the cutoff. It becomes a meaningful cost mainly for swing trading or longer-term positions held for days or weeks. Traders who cannot pay or receive interest for religious reasons should look for a swap-free Islamic account.

Other costs to watch for

• Inactivity fee: some brokers charge a periodic fee if an account has no trading activity for an extended period (commonly several months to a year, varies by broker).
• Deposit/withdrawal fees: less common with major payment methods, but worth checking, especially for international bank transfers or certain e-wallets.
• Currency conversion fees: if your account’s base currency differs from the instrument you’re trading or the currency of your deposit method, a conversion charge may apply.

How to calculate the true cost of a trade

1. Identify the spread in pips for the instrument, and convert it to a monetary value based on your pip value and lot size.
2. Add any per-lot commission (multiplied by however many lots, and by two if the broker charges “per side” rather than “round turn”).
3. If you plan to hold overnight, check the swap rate for that specific pair and direction (long or short), and multiply by the number of nights held.
4. Total these three components for a realistic all-in cost, then compare that figure — not just the headline spread — across brokers or account types.

This total-cost approach matters most for frequent traders and scalpers, where costs compound quickly across many trades — see our guide on scalping forex for more on cost sensitivity in high-frequency strategies. For less frequent, longer-term traders, swap accumulated over a multi-week hold can matter more than the initial spread.

Comparing costs across brokers fairly

Because pricing structures differ (spread-only vs. spread-plus-commission, fixed vs. variable), the only fair comparison is the total, realistic cost for your typical position size and holding period — not a single advertised number. When researching brokers, look at the account type documentation directly rather than relying on homepage marketing. FinPip’s reviews of brokers such as IC Markets, Pepperstone, IG and XM break down each broker’s spread and commission structure by account type, which is a useful starting point for building your own total-cost comparison. For the broader picture of what else to check beyond cost, see how to choose a forex broker.

Remember that trading costs are only one part of the risk equation. Forex and CFD trading is leveraged and can result in losses that exceed the amount you intended to risk on a single trade — always factor costs into your risk management, not just your profit targets.

Key takeaways

• Total trading cost combines the spread, any commission, and swap (for overnight positions) — not the spread alone.
• Spread is paid automatically on every trade; commission is a separate, explicit per-lot fee common on ECN/raw accounts.
• Swap only applies to positions held past the broker’s daily rollover cutoff and varies by currency pair, direction and broker.
• Always calculate the total, realistic cost for your actual position size and holding period before comparing brokers or account types.
• Frequent traders and scalpers are far more sensitive to spread and commission; swing and position traders should pay closer attention to accumulated swap costs.