Spread betting costs extend beyond the difference between the buy and sell prices. Overnight financing, contract rollovers, dividend adjustments and optional service charges can all affect the amount left in your account. A trade can move in the right direction and still lose money after costs.
The useful comparison is not “Which provider advertises the narrowest spread?” It is “What would this position cost at my stake size, during my trading hours, for my expected holding period?” This guide covers that calculation for UK financial spread betting. All numerical examples are hypothetical, not live prices or provider fee quotes.
Separate Trading Costs from Account Adjustments
Start by separating three categories: charges built into the dealing price, charges deducted separately, and adjustments intended to reflect changes in the underlying market. Treating every debit as a fee, or every credit as profit, can give you a misleading result.
Spreads, financing and account charges deserve separate attention. The ESMA Q&A on speculative products and cost disclosure distinguishes dealing markups, funding charges, funding markups and account fees. That distinction provides a useful structure for reviewing a spread betting tariff, rather than accepting “commission free” as the whole answer.
Margin belongs in a different category. It is money required to support the position, not an opening fee. Do not subtract the margin deposit when calculating trading profit. Equally, do not use it as the assumed basis for financing: the exposure being funded can be much larger.
How to Calculate the Spread Cost
The bid is the price at which you can sell; the offer is the price at which you can buy. Their difference is the spread. For a straightforward quote:
Spread cost in pounds = spread in points × stake per point.
Suppose an index is quoted at 7,999–8,001 and you buy at £5 per point. You enter at 8,001. If you immediately close at the unchanged bid of 7,999, the result is a £10 loss: two points multiplied by £5.
That is one full spread across the completed trade, not two full spreads. Relative to an unchanged midpoint, you have paid half on entry and half on exit, assuming a symmetrical quote. With different entry and exit spreads, the equivalent cost is half of each spread, multiplied by the stake.
These calculations depend on the contract’s definition of a point. A decimal movement on the screen is not necessarily one stake unit. Check the dealing ticket before applying the arithmetic; the guide to stakes per point and profit calculations covers that distinction.
Do Not Deduct the Spread Twice
If you calculate profit using actual execution prices, the spread is already included. Buying at 8,001 and selling at 8,021 produces a 20 point gain before separately booked charges. Subtracting another spread would understate the result.
If you instead measure movement between chart midpoints, you need an allowance for the entry and exit spread. Keep these two methods separate, particularly when comparing a backtest with an account statement.
For budgeting, use the spread available during your intended trading session, not just an advertised minimum. Record the quote, time and stake size. A cost estimate without those details is difficult to reproduce and even harder to challenge.
Overnight Financing: The Holding Period Matters
A daily funded bet can attract financing when it remains open across the provider’s stated funding cutoff. For many cash share and index contracts, the calculation uses the position’s notional value rather than the margin deposited. The same full exposure funding principle appears in MoneySense’s explanation of derivative financing calculations.
A useful estimation formula, where the contract uses an annual percentage rate, is:
Funding = notional exposure × annual funding rate × chargeable days ÷ day-count basis.
Assume an index level of 8,000 and a stake of £5 per index point. The notional exposure is approximately £40,000. At an illustrative annual funding rate of 7%, using a 365 day basis, one chargeable day costs:
£40,000 × 0.07 ÷ 365 = approximately £7.67.
Seven chargeable days would cost approximately £53.70 if the exposure and rate stayed constant. Even if the required margin were only £2,000, calculating interest on £2,000 would produce the wrong estimate under these assumed terms.
Use the actual contract formula when checking a statement. Confirm whether the provider uses an opening value or a daily valuation, a 360 or 365 day basis, and an annual rate or a daily rate. Forex and commodity contracts may use different methods, so the index example is not a universal calculator.
Benchmark Rates Are Not the Final Customer Rate
When a tariff specifies a benchmark plus an administration charge, include both. SONIA, for example, measures overnight sterling wholesale borrowing rates; it is not a retail trading tariff. The Bank of England’s SONIA benchmark description sets out what that reference rate represents.
If hypothetical terms specify a 4% benchmark plus a 3 percentage point markup, the annual customer rate is 7%, not 4%. Check whether the markup is expressed as an annual percentage, a daily percentage or points. Mixing those units can turn a small spreadsheet error into a very expensive forecast.
Check Cutoffs, Weekends and Short Positions
Before holding overnight, establish the cutoff time and timezone, which calendar days the charge covers, and how holidays affect the schedule. Do not assume that five trading sessions mean five funding days, or that opening shortly before a cutoff buys you a full day before the first charge.
Nor should you assume a short position earns interest. Check the quoted debit or credit for that direction and any separate share borrowing charge. If you hold matching long and short positions, do not assume their funding cancels. The FCA’s November 2025 review of CFD price and value identified firms charging overnight funding separately on matched positions, alongside weaknesses in funding disclosure and assessment.
Futures and Forward Bets: Costs Can Be Embedded
A contract without a separate nightly funding debit is not necessarily free to hold. For equity index futures, interest rates and expected dividends affect the relationship between the futures price and the cash index. The CME Group calculation of stock index futures fair value shows how these inputs enter the price.
For a futures or forward spread bet, compare the quoted spread, the contract’s pricing basis, its expiry and any rollover terms. Keep the underlying futures premium or discount separate from the provider’s dealing spread. They are different parts of the calculation, even though both appear in the price you trade.
A simple illustration shows why the holding period changes the comparison. Suppose a daily funded contract has a £10 spread cost and estimated funding of £7.67 per day. An alternative dated contract has a £40 spread cost and, under its hypothetical terms, no separate daily funding debit.
The £30 spread difference equals about 3.9 days of the assumed funding charge. That is a screening calculation, not proof that the dated contract becomes cheaper after four days: pricing basis, changing rates and exit terms still matter. The fuller comparison belongs in daily funded bets versus futures and forward bets.
At rollover, distinguish the price difference between contract months from an actual dealing charge. Ask what closes, what opens, which spreads apply and whether any adjustment is booked. A higher quotation for the next contract does not, by itself, identify the rollover fee.
Dividend and Corporate Action Adjustments
For cash share and index spread bets, dividend adjustments generally compensate for the dividend effect on the reference price. Long positions commonly receive a credit and short positions a debit, subject to the contract terms. These are contractual adjustments, not dividends received through share ownership.
Consider a simplified cash index example. You hold a long position at £5 per point, and the contract receives an eight point dividend adjustment. A full adjustment would credit £40. If the price simultaneously falls by eight points solely because of that dividend effect, the position loses £40 in price terms. Before other changes or charges, the two entries offset.
The credit is therefore not a free £40 return. Equally, the debit on a short position should be assessed alongside the corresponding price movement. Actual market prices can move for other reasons at the same time.
Check the adjustment amount, eligibility cutoff and any deductions rather than assuming a full gross credit. Share splits, rights issues and other events may require changes to the contract too. The guide to spread betting on shares and corporate actions covers those events without confusing them with ordinary dealing fees.
Other Charges and Execution Costs
Read beyond the spread and funding table. Potential items include guaranteed stop premiums, market data subscriptions, platform charges and account administration fees. These categories also appear in ASIC’s derivative trading fee checklist. Their inclusion in a checklist does not mean every provider charges them.
For a guaranteed stop, establish whether the premium applies when placing the order, when it triggers, or under another stated condition. For subscriptions, check the billing period and any activity requirement for a rebate. Do not place unnecessary trades just to earn a fee waiver: compare the waiver with the extra trading costs first.
Where a payment or account entry needs currency conversion, identify the exchange rate and markup. Check the currency of the stake, settlement and charges separately rather than assuming an overseas underlying market always creates a conversion fee.
Keep slippage separate from the provider’s published tariff. It is the difference between your reference or expected execution price and the actual fill. When using actual fills to calculate profit, that execution effect is already included, just as the spread is.
A Worked Cost Budget
Return to the hypothetical £5 per point index trade. Assume the midpoint rises by 40 points, the spread stays at two points, and the position incurs seven days of funding. Exposure is held constant for this estimate, with no dividend adjustment, slippage or other fees.
| Component | Calculation | Amount |
|---|---|---|
| Midpoint price gain | 40 points × £5 | £200.00 |
| Spread cost | 2 points × £5 | −£10.00 |
| Funding | £40,000 × 7% × 7 ÷ 365 | −£53.70 |
| Net result | £200 − £10 − £53.70 | £136.30 |
The £63.70 cost budget represents 12.74 points at this stake. Under these assumptions, the midpoint must move that far in your favour just to cover costs. A ten point favourable move would still leave a net loss.
If you start with actual entry and exit fills instead, the price profit here would already be £190. You would then subtract £53.70 of funding, not another £10 spread.
Make the Estimate Before Opening the Trade
Save the contract details and build a cost estimate for both your intended holding period and a longer one. Include the actual spread, funding direction, chargeable days, possible adjustments and optional fees. Then compare the estimate with the statement after closing.
For reconciliation, use executed price profit or loss, add contractual credits, and subtract separately booked debits. Investigate unexplained differences while the quote, trade confirmation and fee schedule are still available.
The narrowest spread is only one part of a cheaper trade. Your stake, timing and holding period determine how much the full package costs. Price risk remains separate: reducing charges cannot make a losing trading approach profitable by itself.