Swap Rollover Calculator: Carry Cost and Yield Reality
Why this page matters
Rollover can either support or drain strategy returns depending on pair direction and holding time. Swing systems must model swap as part of expectancy, not as an afterthought in broker statements.
{ Pre-execution checklist }
Swap direction for long/short is verified for the instrument.
Triple-swap day impact is included in the model.
Holding horizon is defined before entry.
Swap-adjusted expectancy remains acceptable.
Central-bank event calendar is checked.
Calculation logic and practical workflow
Core estimate: Daily Swap Cost = Swap Rate per lot × Lots × Nights Held.
Include broker contract format: some brokers publish points, others currency per lot.
Account for triple-swap day where 3-day financing is booked.
If strategy holds across week boundaries, model full calendar effect, not average daily shortcut.
Build two scenarios: normal carry environment and central-bank-volatility environment.
Compare expected trade edge to projected swap drag; avoid setups where financing consumes edge.
For carry-style setups, validate positive swap sustainability under policy divergence changes.
Common mistakes to avoid
Ignoring triple-swap day and being surprised by large overnight debit.
Assuming swap terms are static; brokers can revise schedules.
Keeping losing positions longer because swap is positive, which distorts risk logic.