Corridor runway calculator
Corridor runway is how many days a prefunded corridor lasts at its current net outflow. Enter a balance, daily payouts and your top-up lead time to see when the corridor runs dry and whether you need to top up now.
How the calculation works
Runway equals the current balance divided by net daily outflow, where net outflow is average daily payouts minus top-ups already arriving each day. Required cover equals net daily outflow multiplied by your lead time in business days plus any destination bank holidays in that window.
Illustrative example: a corridor holds 500,000 and pays out 120,000 a day with no top-ups arriving. Runway is 500,000 / 120,000 = 4.2 days. With a 2 day lead time and 1 holiday, required cover is 120,000 x 3 = 360,000, so there is 140,000 of headroom.
This is a planning estimate from averages. Real outflows spike around paydays and holidays, so check the result against your own history. See the holiday calendars for closure dates and the glossary entry on corridor runway.
Frequently asked questions
What is corridor runway?
Corridor runway is the number of days a corridor's prefunded balance lasts at the current net outflow rate, counting top-ups already in flight. It tells treasury when the next top-up must land.
How much buffer should I keep?
Keep at least enough to cover outflows during your top-up lead time plus any bank holidays in that window. Many teams add a safety margin on top for demand spikes; size it from your own history.
Why do holidays matter?
If the destination banks or rails close, a top-up cannot land until they reopen, while payouts may continue from the prefunded balance. Each closed day extends the lead time you must cover.
Know where all your money is.
Polynopsis gives cross-border payment teams one live position across every bank, payout partner, exchange and wallet, including money in flight, and warns before a corridor runs dry.