Effective trading cost calculator

Input meaning and formula

Notional is the dollar exposure, not margin. Executions is 1 for entry only or 2 for entry and exit. Fee (%) applies per execution; the same notional and fee rate are used on both legs. Funding (%) is the cumulative signed cost over your chosen holding period: positive for a payment, negative for a receipt. It is not automatically multiplied by time or executions.

Spread and slippage (%) are total scenario costs relative to notional. Each is applied once, even when you select two executions. For a round trip, enter a combined estimate covering both legs. Total = N × fee% ÷ 100 × executions + N × funding% ÷ 100 + N × (spread% + slippage%) ÷ 100. Basis points = total ÷ N × 10,000; 1 bp = 0.01%.

Worked example

Hypothetical inputs, not current exchange rates: notional $10,000; entry + exit (2 executions); fee 0.06% per execution; cumulative funding cost +0.01%; total spread cost 0.02%; total slippage 0.03%.

Entry fee: $10,000 × 0.06% = $6. Exit fee: another $6. Trading fees: $12. Funding: $10,000 × 0.01% = $1. Spread: $2. Slippage: $3. Spread + slippage output: $5. Total: $12 + $1 + $2 + $3 = $18, or 18 bps (0.18%) of notional.

With funding entered as −0.01%, the funding output is −$1 and total becomes $16 (16 bps). This is a modeled receipt, not guaranteed future funding. The same inputs with one execution and +0.01% funding produce $12 (12 bps).

Avoid double-counting costs

If slippage already measures execution shortfall from the mid-price, it may include spread; adding full spread again would double-count it. Keep the reference price and definitions consistent. The model does not simulate depth, change exit notional with price or fetch your account fee tier.

Use the existing funding calculator to estimate a holding-period amount, then convert it to a signed percentage of notional for this input. Compare risk in the position size calculator. Use live funding context and your venue’s official fee schedule for actual inputs; settlement intervals and account terms can differ. Copy result and Share setup preserve the current calculation without creating another tool.