How this calculator works
Total monthly cost = spread + commission + swap. Spread is per round-trip × pip value × lots × trades. Commission is per lot × trades. Swap is per lot × nights × trades.
Even small differences in spread compound dramatically across hundreds of monthly trades.
Trading example
40 trades/month at 1 lot EUR/USD: a 0.4-pip spread broker saves ~$160/month vs a 0.8-pip broker. Annualized: $1,920.