Anchor Rode & Scope Calculator
Work out how much rode to deploy for a safe scope, from water depth, tidal rise, bow height and your chosen scope ratio.
At the bow. Scope is a ratio, so any unit works — feet in, feet out; metres in, metres out.
How anchor scope is calculated
Rode = (depth + tidal rise + bow height) × scope ratio. The height from the seabed to your bow roller is what the scope ratio multiplies — not just the charted depth — so tide and freeboard must be included.
Choosing a scope ratio
- 5:1 — settled weather, all-chain rode.
- 7:1 — general anchoring, the common default.
- 10:1 — heavy weather or mostly-rope rode.