tool · Order execution
Slippage Cost Calculator for Buy and Sell Transactions
Slippage compares a recorded execution with a specified reference price. Choose the transaction side, enter the two prices and quantity, and the tool reports adverse movement as positive and price improvement as negative.
Key points
- Select buy or sell for the actual transaction, including when closing a position.
- The reference price and timestamp determine what is being measured.
- Slippage is not a direct measurement of latency or every trading cost.
Slippage cost calculator
The starting numbers are illustrative inputs. Replace them with a consistent scenario. Calculations run in your browser; no account connection or live market data is used.
Formula and boundaries
Buy: adverse price difference = actual − planned. Sell: planned − actual. Slippage amount = adverse difference × units × conversion rate.
- Choose the executed transaction side (buy or sell), rather than the overall position direction.
- This is a linear unit-price model. Enter the full underlying unit quantity; futures and CFDs may require a contract multiplier first.
- Positive output is adverse slippage; negative output is price improvement. Commissions, spread attribution and latency are not included.
Define a reference that can be reproduced
A fill can be compared with a decision price, an order-submission quote or another clearly recorded benchmark. Those comparisons answer different questions. Save the timestamp, bid/ask basis, instrument and quantity associated with the planned price. A chart midpoint observed later is not a reliable substitute for the original executable quote.
The calculator uses actual minus planned price for a buy transaction and planned minus actual for a sell. Positive values are adverse; negative values represent improvement. It divides the difference by your chosen price increment and multiplies by underlying units and a quote-to-account conversion rate to obtain a monetary amount. Order mechanics and execution conditions are described in cTrader's order documentation.
Check both sides with the same example
Assume a buy reference of 1.1000, an actual fill of 1.1003, a quantity of 20,000 underlying units, a price increment of 0.0001 and conversion rate of 1. The adverse difference is 0.0003, corresponding to three increments. The modeled slippage amount is 0.0003 × 20,000 = 6 account-currency units.
For a sell using those same two prices, the amount is −6 because selling higher is favorable. To show adverse sell slippage, use a reference of 1.1000 and an actual fill of 1.0997. The tool again reports +6. This sign convention also applies to an exit: selling to close a long position is a sell transaction even though the position being closed was long.
Resolve contract and conversion dimensions
Quantity means full underlying units in a linear quoted-price model. If a platform shows lots, convert them using the correct contract size. A futures contract multiplier may also be required before a price difference can become cash. The generic tool does not infer those specifications or handle every inverse payoff.
The conversion rate means account currency per one unit of quote currency. It is 1 when both currencies match. Rates are supplied by you and are not live. Likewise, the comparison increment can be a full pip or another verified price step, but label it consistently when recording the result. Changing the increment changes the displayed count, not the underlying monetary difference.
What this amount does not attribute
A price difference alone cannot separate network delay, price movement, spread changes, market impact and order-book depth. Commissions and financing are also separate unless deliberately incorporated into a broader accounting method. Do not label all measured slippage as a software routing delay.
Partial fills require a quantity-weighted fill price or separate calculations for each fill. Compare like-for-like quantities; missing or rejected volume needs its own record. The tool rejects non-positive prices, quantity, increment or conversion, and it does not send orders. Its output supports a transparent execution worksheet, not a guarantee that a broker or copier will obtain the planned price.
Questions and answers
Why is the slippage amount negative?
Under this convention, a negative result means the fill improved on the entered reference: a lower buy price or a higher sell price.
Can this prove that routing latency caused the price difference?
No. Price differences can have several causes. A latency investigation needs synchronized timestamps and execution evidence in addition to prices.
Sources and further checks
Use the current source for your exact instrument, account and platform. Referencing a general specification does not establish support for every TradeCopier workflow.
- cTrader: order mechanics · Checked September 19, 2026
- CME: price change and contract profit or loss · Checked September 19, 2026
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