Trading Cost Calculator
Add commission, spread, slippage and fees into the true round-trip cost of a trade, and the move needed to cover it.
Every other calculator on this site reports a gross figure. This trading cost calculator reports the total cost of a trade — the round-trip cost of commission, spread, slippage and fees together — which is the difference between a strategy that works on paper and one that works in an account.
Formula: total = commission + (spread + slippage) x units + fees
Your figures
How your broker charges. All three are round-trip.
Round-trip, in the unit the basis above describes. The default is a round illustrative figure, not any broker's rate — replace it with the one on your own contract specification, or set it to zero for a commission-free account.
In units of the instrument. This is the size every cash figure is computed from; the lots field below is read only when commission is charged per lot.
In lots. Only used for per-lot commission.
In price units.
Exchange, clearing or platform charges.
Results
Total round-trip cost
US$60.00
1.2000% of a US$5,000.00 position
- Commission
- US$10.00
- Spread and slippage
- US$50.00
- Other fees
- US$0.00
- Break-even movePrice movement needed to cover every cost.
- 0.60000000
- Break-even move as a percentage
- 1.2000%
- Commission's share of the total
- 16.7%
- Execution's share of the total
- 83.3%
- Position value
- US$5,000.00
What this means
Opening and closing this position costs US$60.00 in total, of which 17% is commission and 83% is spread and slippage. Price must move 0.600000 — 1.200% — simply to get back to level. The two components respond to different things, which is why they are worth seeing apart: commission tends to scale with size, while the spread is a fixed distance and so hurts short-term trading most.
- Every figure here is broker-specific and must come from your own contract specification or statement. No broker's or venue's figure is preset: where a field opens with a number it is a round illustration to overwrite, because commission, spreads and rates differ by broker, venue, instrument and account tier, and all of them are revised.
- All three commission bases are round-trip, matching how brokers quote them. If yours quotes per side, double it before entering.
- Excludes overnight financing, swap and funding, which accrue with time rather than per trade.
Total round-trip cost: US$60.00
The link reopens this calculator with the same numbers. Nothing you enter is sent to a server.
Continue with these figures
About the Trading Cost calculation
Costs are unusual in being paid on winners and losers alike. A stop-out costs the loss plus the costs; a winner pays them too, out of the profit. They scale with how often you trade rather than with how well, which is why they punish frequency far more than they punish being wrong.
As a cost per trade calculator it separates commission from spread and slippage rather than reporting one number, because the two respond to entirely different things and the balance between them tells you where your costs actually come from.
Trading Cost formula
commission, by basis:
per lot = commission × lots
fixed = commission
% of notional = notional × commission ÷ 100
execution = (spread + entry slippage + exit slippage) × units × FX
total = commission + execution + other fees
break-even move = total ÷ (units × FX)- round trip
- Opening and closing together, which is how brokers quote commission.
- notional
- Entry price × units — the position's value, not the margin posted.
- break-even move
- How far price must travel before the trade is worth nothing.
All three commission bases are round-trip, matching broker convention. If yours quotes per side, double it before entering — it is the single most common error in cost arithmetic and it halves every figure here.
Commission and execution scale differently with size, which is why the split matters. A fixed commission becomes proportionally smaller as the position grows, so it dominates small trades and disappears on large ones. The spread is a fixed *distance*, so its cash cost grows exactly in step with size and its percentage cost never falls at all.
The break-even move is the figure worth carrying away. It converts every cost into the only unit that matters at the moment of entry: how far the market has to go in your favour before you have made nothing.
Trading Cost: a worked example
100 units at 50.00, with a round-trip commission of $10 per lot on one lot, a 0.50 spread and no slippage. These are the figures the page loads with.
- Position value50 × 100 = $5,000
- Commission$10 × 1 lot = $10.00
- Execution cost0.50 × 100 = $50.00
- Total round trip$60.00
- As a share of the position60 ÷ 5,000 = 1.20%
- Break-even move60 ÷ 100 = 0.60
$60 to open and close, and price must move 0.60 — 1.20% — before the trade is level. Note that the spread is 83% of the cost here, not the commission.
How to use the Trading Cost calculator
- Choose the basis your broker actually uses. Per lot, a flat charge and a percentage of notional produce very different answers at different sizes.
- Enter commission as a round-trip figure, doubling a per-side quote. To use the page as a commission calculator on its own, leave the spread and slippage fields at zero.
- Enter the spread in price units, taken from a live quote rather than the broker's advertised typical.
- Add expected slippage if you trade around news or in thin markets, where it is often larger than the spread.
- Read the break-even move alongside the total. That line is what makes this a break-even move calculator as well as a cost one: it tells you whether the trade is worth taking at all.
Limitations of the Trading Cost calculator
Every calculation makes assumptions. These are the ones that matter here.
- Excludes overnight financing, swap and funding, which accrue with time rather than per trade. Those have their own calculators.
- Assumes the spread you enter is the spread you get. It widens in thin markets, around scheduled news and at session boundaries.
- Excludes any transaction tax, which is charged on the value of the trade in several jurisdictions.
- Assumes commission is charged as described. Tiered, volume-based and rebated schedules are not modelled.
Frequently asked questions about Trading Cost
Should I enter commission per side or round trip?
Round trip. All three bases here assume the figure covers opening and closing, which is how brokers normally quote it. If yours quotes per side, double it — entering a per-side figure halves every result on this page.
Why separate commission from the spread?
Because they behave differently. Commission is often fixed or per lot, so it matters most on small positions. The spread is a fixed distance, so its percentage cost is identical at every size and it never becomes negligible. Knowing which dominates tells you whether trading larger or trading less often is the lever.
Is the spread really a cost if I use limit orders?
Partly. A limit order that fills at your price avoids crossing the spread, but it also does not always fill — and the trades it misses are disproportionately the ones that would have worked. The spread entered here is best read as the cost of guaranteed execution.
Why is my cost percentage so high on a small trade?
Because fixed costs do not shrink. A $7 commission on a $500 position is 1.4% before the spread; the same $7 on a $50,000 position is 0.014%. This is the main structural disadvantage of trading small, and no strategy overcomes it.
Last reviewed . See our methodology and editorial policy.
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