🔩 Rivet & Snap Spacing Calculator

Enter your total edge length and roughly how far apart you want fasteners to see how many fit and the exact spacing to keep them perfectly even.

Edge length (in)

Desired spacing (in)

Why the count is one more than the gaps

A fastener sits at each end of the run, so the line is a fence problem: the gaps are what your spacing divides into, and the posts are one more than that.

gaps  = floor(edge length / desired spacing)
count = gaps + 1
even spacing = edge length / gaps

The defaults show both halves: 12 in at 2 in gives 6 gaps, 7 rivets, and the spacing stays exactly 2.000 in. Ask for the same 2 in on a 13 in edge and you still get 6 gaps and 7 rivets, but each gap opens to 2.167 in. Rounding the gap count down means the spacing returned is never tighter than you asked, only wider.

Measuring the run

Feed it centre to centre, not edge to edge. The length you type is the distance between the first and last fastener. On a 12 in strap with a 5/8 in setback at each end, run the numbers on 10.75 in.
Keep the rivet off the edge. A centre closer than 1/4 in, or twice the post diameter if that is more, tears out through the grain when the strap is loaded.
Two fasteners at any joint that can rotate. A single rivet on a bag handle is a hinge; a pair holds the tab square.

If the edge is shorter than one gap the tool returns a single fastener and a spacing of 0, which is correct rather than an error. Leaving the spacing box empty makes it assume 1 in.

Frequently asked questions

How many rivets do I need for a 12 inch run at 2 inch spacing?

Seven. Six gaps of 2 in, plus the rivet that closes the far end. Ordering six is the usual mistake.

How far apart should rivets be on a leather strap?

1.5 to 2 in reads as evenly decorative. Where the rivets are structural, such as a handle tab or a belt keeper, use 3/4 to 1 in and always set at least two.

Does this work for snaps and chicago screws?

Yes, the spacing maths is the same for any fastener set on a line. Snaps need more clearance, so check the cap diameter fits the gap before you punch.