A quick way to estimate how much wire you’ll need to make a chain of circular links with the coil & cut method. Make sure you use the same units for each measurement! Equations at the bottom of the page.

For a single ring:

In order to calculate the length of wire needed to make multiple jump rings:

Now, looking at how long a chain of a specific number of links is:

Combining all of that together, we get the length of wire needed to make a chain of given length: