A trade size calculator that also shows the cost per trade
Posted: Fri Oct 30, 2026 7:30 am
I built a small spreadsheet that calculates position size and, next to it, the cost of the trade in R. It's changed which trades I take.
Inputs:
With an 8 pip stop the cost drops to 11% of R. So tight stops look attractive but carry a heavy cost in R terms.
I now skip setups where cost exceeds 20% of R. Do others track cost in R?
Inputs:
- Account size, risk %, stop in pips, pip value per lot.
- Current spread and commission per lot.
- Position size, rounded down to the lot step.
- Total cost of the round turn in money and as a fraction of the risk.
With an 8 pip stop the cost drops to 11% of R. So tight stops look attractive but carry a heavy cost in R terms.
I now skip setups where cost exceeds 20% of R. Do others track cost in R?