Anchor Rode Length Calculator
Fill in the values and the answer updates as you type.
How the Anchor Rode Length Calculator works
Rode length = (water depth + expected tide rise + bow roller height) × scope ratio. Scope is the ratio of rode length to the height from the seabed to the bow roller. A common guide is 5 : 1 with chain in calm weather and 7 : 1 with rope, and 10 : 1 when a storm is coming. The horizontal reach comes from Pythagoras and shows how far from the anchor the boat can swing, before adding the boat length. Always add the high-tide depth, not the depth you see at anchoring time. Example: with Water depth 15 ft, Expected tide rise 4 ft, Bow roller height above water 4 ft, and Scope ratio 7 : 1, the result is Anchor rode to let out (ft) = 161; Anchor rode to let out (m) = 49; Total height used (ft) = 23.
Inputs and results
The Anchor Rode Length Calculator takes 4 inputs and gives 5 results.
What you enter
- Water depth (ft) — starts at 15.
- Expected tide rise (ft) — starts at 4.
- Bow roller height above water (ft) — starts at 4.
- Scope ratio (: 1) — starts at 7.
What you get
- Anchor rode to let out (ft)
- Anchor rode to let out (m)
- Total height used (ft)
- Horizontal reach of the rode (ft)
- Rode for a 10 : 1 storm scope (ft)
Example: Anchor Rode Length Calculator with the starting values
With water depth 15 ft, expected tide rise 4 ft, bow roller height above water 4 ft and scope ratio 7 : 1, the calculator returns:
| Anchor rode to let out (ft) | 161 |
|---|---|
| Anchor rode to let out (m) | 49 |
| Total height used (ft) | 23 |
| Horizontal reach of the rode (ft) | 159 |
| Rode for a 10 : 1 storm scope (ft) | 230 |
Change any value above and the results update straight away.
Anchor Rode Length Calculator FAQ
How do I use the Anchor Rode Length Calculator?
Enter water depth, expected tide rise, bow roller height above water and scope ratio in the fields, then read anchor rode to let out (ft), anchor rode to let out (m), total height used (ft) and horizontal reach of the rode (ft) in the result panel. The answer updates as you type, and you can press Calculate or Enter to refresh it. Use “Copy link” to share your exact numbers with someone else.
What does the Anchor Rode Length Calculator calculate?
How much anchor line and chain to let out for a safe scope. It returns anchor rode to let out (ft), anchor rode to let out (m), total height used (ft) and horizontal reach of the rode (ft) from the 4 values you provide.
What values does the Anchor Rode Length Calculator start with?
It opens with water depth 15 ft, expected tide rise 4 ft, bow roller height above water 4 ft and scope ratio 7 : 1 so you can see a working result straight away. Replace them with your own numbers, or press Reset to return to these starting values.
Is the Anchor Rode Length Calculator free and private?
Yes. It is free, needs no account, and runs in your browser, so nothing you type is sent to or stored on our servers. See the Privacy Policy for details.
Can I rely on the Anchor Rode Length Calculator for important decisions?
Treat the result as a well-rounded estimate. Real situations often have details a general calculator cannot know, so confirm important decisions with a qualified professional. See the Disclaimer for more.