The true cost of a crypto trade: spread, slippage and fees

The fee line is only one part of the picture

A receipt can show a small commission while the price you actually received creates a larger difference against your reference price. A sensible review distinguishes explicit charges from execution-price effects. The order-book spread is the gap between the best available bid and ask. Slippage describes a difference between an expected execution and the actual result. These concepts explain why comparing two commission percentages alone is insufficient to compare the cost of otherwise similar completed orders.

Choose a benchmark before doing arithmetic

Write down what expected price means in your worksheet. It might be the midpoint at decision time, the best ask immediately before a buy, or a firm quote you accepted. Each benchmark answers a different question. Mixing the midpoint for one trade with the last traded price for another makes the comparison unstable. Preserve the timestamp and source of the reference alongside the actual average fill. A chart candle's closing price is not automatically the executable price for your order.

A worked example that avoids double counting

Suppose a hypothetical book shows a bid of 99 USD and an ask of 101 USD. Its midpoint is 100 USD. Buying ten units entirely at 101 USD costs 1,010 USD before commission. Compared with the midpoint, the execution difference is 10 USD. If the separate commission is 1 USD, the benchmark-based cost is 11 USD. Do not add another 20 USD for the full two-dollar spread: your execution difference already reflects crossing from midpoint to ask.

Separate depth effects from the initial spread

Now assume only five units are available at 101 USD and the next five fill at 102 USD. The average execution is 101.50 USD, so the purchase costs 1,015 USD before commission. Against the same midpoint, the difference is 15 USD. You can explain it as 10 USD from the initial midpoint-to-ask gap and 5 USD from the additional depth effect. Alternatively use the single 15 USD number. Adding both representations together would count identical price effects twice.

Compare like-for-like products and quotes

An instant conversion interface and an order-book interface may package charges differently. Kraken's fee schedule distinguishes its products and explains when a quoted price includes spread and fees. Read the relevant screen before assuming every cost will appear as a separate commission line. For a useful comparison, hold quantity, currency, approximate time and transaction direction constant. Also distinguish an indicative quote from a completed fill. A quote that was never executable for your requested size is a weak benchmark.

Build an honest net-cost worksheet

Use columns for quantity, reference price, average execution, explicit commission and any separate funding or transfer costs within your chosen scope. For a buy, quantity multiplied by execution minus reference is the price difference; for a sell, reverse the subtraction. A favorable difference should remain negative rather than being erased. Subtract confirmed cashback separately and only once. The result is a transparent estimate of cost relative to your chosen benchmark, not proof that another venue would have filled the same order at that price.