The real cost of a CFD trade: spread, commission, swap and slippage

Most traders who assess a CFD or Futures trade focus on the entry and the exit price. The difference between the two determines the P&L. That arithmetic is correct as far as it goes, but it does not go far enough.

The costs embedded in a CFD trade do not appear as a single line item. They are distributed across four distinct mechanisms, each with its own logic, each applying at a different point in the trade lifecycle, and each capable of turning a theoretically profitable position into a losing one if underlying cost benefit analysis are left unexamined. Understanding them with precision is a prerequisite for making accurate decisions about position sizing, hold duration, and the realistic profitability threshold a trade must clear before it is worth taking on a trade.

This is a breakdown of all four.

The Spread: The Cost You Pay Before the Trade Moves

The spread is the gap between the price at which you can buy a CFD (the ask) and the price at which you can sell it (the bid). When you open a position, you begin with an immediate unrealised loss equal to the spread. The market needs to move in your favour by at least the spread width before you are at breakeven.

For a liquid instrument, the spread is typically narrow. On a major currency pair such as EUR/USD during peak trading hours, a spread of 0.5 to 1 pip is normal with a competitive broker. On an index CFD such as the FTSE 100, a spread of one to two points is typical. On a less liquid instrument, a single-stock CFD in a mid-cap company or an exotic currency pair, the spread widens considerably. It can represent a materially larger fraction of any expected move.

The practical question to ask about any instrument before trading is what the all-in entry cost looks like in basis points relative to the move you are trying to capture.

A worked example on EUR/USD

The ask is 1.08503, and the bid is 1.08498. The spread is 0.5 pips. On a standard lot of 100,000 units, that spread represents a cost of $5.00 at the point of entry. The market needs to move 0.5 pips in your favour before you have covered the cost of opening the trade.

If the expected trade duration is a few hours and the anticipated move is 20 pips, that $5.00 spread cost is a small fraction of the potential return. If the anticipated move is 5 pips, the spread represents 10 per cent of the target before any other costs are considered. The spread’s materiality is always relative to the intended holding period and the expected price movement.

Commission: The Transparent Fee and What to Watch For

Some CFD accounts charge an explicit commission per trade rather than embedding the cost in the spread. In those cases, the spread will typically be tighter, and a fixed or percentage-based fee is applied at the opening and closing of the position.

Commission structures vary in ways that matter. A common structure in shares CFDs is a percentage of the notional trade value, typically in the range of 0.1 to 0.3 per cent per side. A round trip, opening and closing the position, therefore costs between 0.2 and 0.6 per cent of the notional value before any market movement is factored in.

On a £10,000 notional position in a shares CFD with a 0.2 per cent round-trip commission, the cost of entry and exit is £20.00. That position needs to appreciate by at least 0.2 per cent before the commission is covered, leaving any actual profit to come on top of that threshold.

For forex and index CFDs, many brokers embed the cost in the spread rather than charging an explicit commission. The relevant comparison is between the all-in spread cost on a no-commission account and the narrower spread plus explicit commission on a raw spread account. For high-frequency traders who open and close many positions in a session, the raw spread-plus-commission structure is usually cheaper. For traders who hold positions for longer periods, the distinction matters less relative to the overnight financing cost, which is covered in the next section.

The important discipline is to calculate the total round-trip cost, spread plus commission both ways, before opening a position. This is the minimum move required simply to break even.

The Overnight Swap: The Cost That Compounds Against You

The overnight financing charge, often called the swap rate, is the cost of holding a leveraged CFD position open beyond the daily market close. It is the most frequently underestimated cost in CFD trading because it is not paid at the time a trade is opened. It accrues quietly, applied each night the position remains open, and it compounds over time.

The mechanism behind the swap rate is the cost of carry. When you hold a long CFD position, the broker is in effect funding your leveraged exposure. The overnight charge reflects the interest cost of that funding, typically linked to a benchmark rate such as Secured Overnight Financing Rate (SOFR) or the base rate of the relevant currency, plus a broker margin.

The direction of the swap matters as well as its magnitude. On a long position in a currency pair where the base currency carries a higher interest rate than the quote currency, you may receive rather than pay a swap. On most equity index CFDs, however, the swap is a cost rather than a credit, applied to long positions each night. The broker publishes the rate, which should be checked before deciding to hold any position overnight.

Why the compounding effect deserves specific attention

The swap rate on a single night is usually a small absolute figure. On a £50,000 notional long position in an index CFD at an annualised financing rate of 5.5 per cent, the overnight charge is approximately £7.50 per night. Over a week, that is £52.50. Over a month, it is approaching £225. Over three months, the financing costs alone exceed £675.

A position that looks profitable on a mark-to-market basis over a three-month hold may look materially different once the accumulated swap is deducted.

The overnight financing cost is covered in more depth in a dedicated article on overnight financing and its impact on profitability.

Slippage: The Cost That Appears When You Can Least Afford It

Slippage is the difference between the price at which you intended to execute a trade and the price at which it was actually filled. It applies most acutely to market orders during conditions of high volatility or low liquidity, when the price moves between the moment you submit the order and the moment it is filled.

Under normal market conditions, slippage on liquid instruments is negligible. A market order on EUR/USD during the London session will typically be filled at a price within a fraction of a pip of the quoted price. The spread covers the known cost, and slippage adds very little.

Under abnormal conditions, slippage can be significant and can operate in eitherdirection, though the direction that hurts the trader is more pertinent. The circumstances that generate material slippage are predictable: major economic data releases such as Non-Farm Payrolls or central bank rate decisions, market opens after weekend gaps, geopolitical events that hit the news during low-liquidity hours, and earnings announcements for single-stock CFDs. In any of these situations, the price can move sharply between order submission and execution.

Slippage on a stop-loss order is particularly consequential. A stop-loss is placed to limit the maximum loss on a position. If the market gaps through the stop level, the order is filled at the price available at execution, which may be materially worse than the stop price. On liquid instruments during normal conditions, this gap will be small. On illiquid instruments, or during the events described above, the gap between the stop price and the actual fill price can be material.

Guaranteed stop-loss orders

A guaranteed stop-loss order (GSLO) eliminates slippage on the stop-loss by guaranteeing execution at the nominated price, regardless of market conditions. The broker charges a premium for this guarantee, either as a fixed fee or as a slightly wider spread on the position. For positions held through known high-risk events, the premium may be worth paying. The decision is a straightforward calculation: does the cost of the guarantee represent an acceptable insurance premium relative to the maximum additional loss that slippage could generate if the stop is breached during a fast move?

Putting It Together: What the All-In Cost Looks Like

The four costs above do not operate independently. They accumulate and interact, and their combined impact on a trade’s profitability should be modelled explicitly before a position is opened rather than rationalised after it is closed.

Consider a long position in an index CFD held for two weeks.

The spread applies at entry and exit. On a typical index CFD with a one-point spread, the round-trip spread cost on a position of ten contracts (at £10 per point) is £20.00 at each end, or £40.00 in total.

The commission, if the account structure charges it, applies at both ends. On a no-commission account where the cost is embedded in the spread, this figure is already reflected in the spread above. On a raw spread account with an explicit commission, it is added separately.

The overnight swap accumulates across fourteen nights. At a modest annualised financing rate on a notional position, this might add £100-£200 over the two weeks, depending on the position size and the prevailing rate.

The slippage is estimated rather than known in advance. On a two-week hold with entry and exit during normal conditions, slippage may be minimal. If the position is closed during a data release or market event, the figure could be higher.

The total all-in cost for the two-week hold on a position of this size might plausibly range from £140 to £280, before any market movement is considered. That is the floor the trade needs to clear just to break even. Every basis point of that cost was predictable before the position was opened.

Why This Matters for Position Sizing and Decision-Making

The purpose of understanding these costs is not purely academic. It is to make the minimum profitability threshold for any trade explicit before it is placed.

A trade that looks attractive at a 1:2 risk-reward ratio on raw price movement may look considerably less attractive when the all-in cost of carry is factored into the breakeven calculation. A position that would need a 15-pip move to cover the spread and commission and a further 20-pip move to cover the swap over a five-day hold needs to move 35 pips into profit before delivering any actual return. If the technical setup only anticipates a 30-pip move, the trade has a negative expected value before the probability of success is even considered.

This is the calculation most retail traders do not make. It is also one of the clearest structural advantages available to any trader who does.

The quality of execution you receive on these costs, the tightness of the spread, the competitiveness of the financing rate, and the depth of liquidity that limits slippage are therefore direct inputs into your trading profitability, not secondary considerations. Choosing the right platform is not a preference. It is a component of the trading decision. Lunaro’s approach to pricing and execution is set out here.

The Bottom Line

The spread, the commission, the overnight swap, and slippage are not footnotes to a CFD trade. They are the infrastructure through which the trade’s profitability is determined. Each has a different mechanism, a different timing, and a different level of predictability.

The spread is known before entry. The commission is known before entry. The swap accrues each night and compounds predictably over the holding period. Slippage is estimated probabilistically, with higher uncertainty during known high-risk events.

Together, they constitute the all-in cost of carrying a position. Calculating that cost explicitly, and ensuring the trade’s realistic expected return covers it before the position is opened, is not a conservative practice. It is a basic standard of analytical rigour.

Traders who apply it consistently make better-informed decisions than those who do not. Over any meaningful run of trades, the difference accumulates.

Joshua Owen is CEO of Lunaro Markets. He has spent over a decade on trading desks at FCA-regulated firms, with a background in risk management, trading, and quantitative finance.

Disclaimer:

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CFDs are complex instruments and come with a high risk of losing money rapidly due to leverage. Approximately 80% of retail client accounts lose money when trading in CFDs. You should consider whether you understand how CFDs work and whether you can afford to take the high risk of losing your money.

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