Calculator
Trading cost calculator
Enter the position size, price, spread, commission and any overnight financing. The calculator shows what the trade costs in money and as a share of the position, before the price has moved at all.
Quick answer
Total cost = units × spread + 2 × commission + financing. With the defaults (10,000 units at 1.10, spread 0.0001, no commission or financing) the cost is $1.00, or 0.009% of the position (calculated). Overnight financing rates vary widely between providers [4].
This calculator needs JavaScript. The formula and a worked example below show the same calculation by hand.
Key points
- Every trade starts behind by its costs: the spread, any commission on opening and closing, and financing while you hold [2].
- Financing grows with every night a position stays open, so holding time can matter more than the spread.
- Zero commission is not zero cost; FINRA says free trading does not mean free investing [7].
On this page
How does the calculator work?#
It adds three costs. The spread is the difference between the bid and the ask price [1]; crossing it once costs units × spread. Commission is counted twice, because some providers charge on both opening and closing a trade [2]. Financing is modelled as a yearly interest rate on the position value, charged for each night you hold. Overnight financing is a common cost on leveraged products such as CFDs [3], and the FCA discusses these charges as effective interest rates [4]. Our sources give no standard formula, so treat this part as an estimate.
total = units × spread + 2 × commission + (units × price) × (rate % / 100) / 365 × nights
It also shows the total as a percentage of the position value (units × price). That is the move the price must make in your favour just to get back to zero. The calculator divides the yearly rate by 365; your provider may use a different day count, so check its terms.
Can you check the result by hand?#
Now add a $3 commission per side and a 5% yearly financing rate, and change the number of nights. The spread and commission stay the same; only financing grows. All figures below are calculated with the same formula and are illustrations, not typical rates: our sources give no standard spread, commission or financing level.
| Held for | Spread | Commission | Financing | Total | Share of position |
|---|---|---|---|---|---|
| Closed same day | $1.00 | $6.00 | $0.00 | $7.00 | 0.064% |
| 1 night | $1.00 | $6.00 | $1.51 | $8.51 | 0.077% |
| 10 nights | $1.00 | $6.00 | $15.07 | $22.07 | 0.201% |
| 30 nights | $1.00 | $6.00 | $45.21 | $52.21 | 0.475% |
| 90 nights | $1.00 | $6.00 | $135.62 | $142.62 | 1.297% |
Costs are in the quote currency, here US dollars. Rates are illustrative.
What does the calculator not account for?#
- Different financing rates. The FCA found wide variations in the effective interest rates retail clients paid through overnight funding charges at different firms [4]. Enter the rate from your own provider.
- Credits on short positions. Some firms charged for overnight short positions where others would have paid the client a credit [4]. The calculator treats financing only as a cost.
- Hedged positions. The FCA found firms charged overnight funding on each position separately, with no offset between long and short positions in the same CFD [4]. The FCA said the cost of holding such hedged positions could be substantial [4].
- Other fees. Account management fees and taxes can also apply [2]. They, and any currency conversion fees, are not included.
- Slippage. The price you get can differ from the quote, which changes the real spread you pay. See slippage.
Why do small costs matter so much?#
Because they repeat. The SEC shows how small yearly fees add up on a $100,000 investment growing 4% a year for 20 years: about $208,000 with a 0.25% fee and about $179,000 with a 1.00% fee [5]. That is roughly $29,000 apart (our arithmetic on the SEC's approximate figures). Trading costs work the same way: each trade starts slightly behind, and frequent trading repeats that loss again and again.
ASIC, the Australian regulator, says leverage and associated financing fees can magnify investor losses [6]. In its 2024 financial year, 68% of retail CFD investors in Australia lost money, totalling more than $458 million as ASIC reports it, including $73 million in fees [6]. Read trading fees explained for each cost in detail, and payment for order flow for how zero-commission brokers are paid.
Frequently asked questions#
What should I enter as the spread?
The difference between the ask and bid price at the moment you trade [1], in the same price units as the price field. For a quote of 1.1000 bid and 1.1001 ask, enter 0.0001.
Why is commission doubled?
Because a round trip has two trades, an opening and a closing one, and some providers charge commission on each [2]. If your provider charges only once, enter half the amount.
Where do I find my financing rate?
In your provider's cost or product information. Rates differ widely between firms [4], so do not copy a figure from another provider or from our example.
Does a low cost mean a trade is a good idea?
No. Costs are only what you pay to take the risk. The price can still move against you by far more than the cost.
The bottom line#
Work out the cost of a trade before you place it, and look hardest at financing if you plan to hold for more than a few days. Use your own provider's spread, commission and rate, not our illustrations. For the size of the trade itself, use the position size calculator, and read the risk disclosure before trading with leverage.
Sources
- Bid Price/Ask Price | Investor.gov.
- Contracts for difference (CFDs).
- Contracts for difference (CFDs) - Moneysmart.gov.au.
- Multi-firm review of contracts for difference providers' provision of price and value.
- How Fees and Expenses Affect Your Investment Portfolio - Investor Bulletin.
- 26-004MR ASIC secures nearly $40 million in refunds to investors and drives change after CFD sector falls short.
- Fees and Commissions | FINRA.org.
Education only. This page is not investment, tax or legal advice. Trading and crypto can lose you money. See our risk disclosure.
