A true-cost worksheet: spread + commission + slippage per trade

[FXS London Scalper]

Ask a scalper what one trade costs and the answer is usually the spread. The real number has at least three parts, and the third one is the one nobody writes down.

A worksheet that fits on one screen, one row per trade:

Column A: spread at entry (pips)
Column B: commission round turn, converted to pips (commission per lot / pip value per lot)
Column C: entry slippage (fill minus intended price, signed)
Column D: exit slippage (same)
Column E: total = A + B + C + D
Column F: total as a fraction of the planned stop

Column F is where the worksheet earns its keep. A 0.9-pip total cost on a 3-pip stop means every trade starts 30% of the way to a full loss. On a 6-pip stop it's 15%. Same broker, same pair, very different strategy.

A few hundred rows later, sort by hour. On many accounts, costs during the first five minutes of London are double those of 08:30–10:00, mostly from slippage, not spread.

Worth doing at least once, even if you never maintain it afterwards. If anyone wants to compare Column F averages, post yours with pair and session; broker names optional.