KD2MRG

# Jump Ring Chain Calculator

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:

$l=\pi (d+t_w)$

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

$l_w = \pi n (d+t_w) + t_b(n-1)$

$l_w = n \bigg( \pi(d+t_w) + t_b \bigg) - t_b$

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

$l_c = nd+2t_w$

$n = \frac{lc-2t_w}{d}$

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

$l_w=\frac{l_c-2t_w}{d} \bigg(\pi (d+t_w) + t_b \bigg) - t_b$