Parts of a Belt Buckle – Frame, Prong, Bar and Chape

All 10 parts on the diagram

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Parts of a buckle 5

Frame The buckle's most visible part. It holds the other parts together.
Prong (tongue) It passes through a hole in the belt. It rests on the far side of the frame. Also called the pin or the tongue.
Keeper A loop of leather, fabric, plastic or metal. It holds the tip of the belt down after it has gone through the buckle.
Center bar It crosses the middle of the frame and holds the prong. Found on a center-bar buckle.
Chape A fixed plate or cover that attaches the buckle to the belt. Because it is often a plate it is also called a buckle plate.

Kinds of buckle 5

Heel-bar buckle The bar is at one end. Nothing holds the belt's tip down, so the belt needs a keeper. Also called a harness buckle.
Center-bar buckle The far side of the frame holds the belt's end down. So it usually needs no keeper.
D-rings The belt is fastened by threading it through the rings. They are used on braided, webbing and canvas belts.
Slide buckle The belt winds through the slots and holds by friction. It can be set to any length.
Side-release buckle One end snaps into the other. Squeezing its two sides lets it go. It is common on outdoor gear.

How this list was compiled: Every name checked on 2026-09-30, a name kept only where two sources use it: Wikipedia, text only: Buckle and Belt buckle, https://en.wikipedia.org/wiki/Buckle (frame, chape or buckle plate, prong also called pin or tongue, bar, center bar, keeper, frame-style buckles, D-ring buckles, belt slides with no prong, side release buckles); a belt-making handbook read through archive.org's full-text search, Making Stylish Belts, https://archive.org/details/makingstylishbel0000gold (center-bar buckle and its center bar, harness buckle with its bar at one side, prong, keeper or belt loop, D-rings, slide buckle, plastic side-release buckle); a leatherwork book read the same way, https://archive.org/details/newbookofleather0000jose (center bar buckle, tongue, keeper, the buckle with no tongue); a costume-making book read the same way, https://archive.org/details/cosplayforyouper0000klam (centre bar buckle with a full frame, heel bar buckle that needs a strap loop, prong); Basic Leathercrafting, https://archive.org/details/basicleathercraf0000unse (heel bar buckle); and, for frame, chape and tongue on old buckles, Carolyn L. White, American Artifacts of Personal Adornment 1680-1820, https://archive.org/details/americanartifact0000whit. Licence: own work

The drawing: Drawn for this site on 2026-09-30 from plain geometry; no maker's shape or mark, nothing traced. Licence: own work

How it works

These are the parts of a belt buckle, and the parts of a buckle on any strap: the frame, the prong and the bar it turns on. The second drawing shows five kinds of buckle.

Read the full guide

Frame, prong and bar

The frame is the part you see; it holds the rest together. The prong, or tongue, goes through a hole in the belt. On a heel-bar buckle the bar is one end of the frame, and a keeper on the strap holds the belt's tip down. On a center-bar buckle the bar crosses the middle, and the far side of the frame holds the tip. A chape is a plate that fixes a buckle to its strap.

Prong, pin and tongue are three names for the same part.
A heel-bar buckle is also called a harness buckle.

Questions and answers

What are the parts of a belt buckle called?

A buckle has four main parts: the frame, the bar, the prong and the chape. The frame holds the others, the bar carries the prong, the prong goes through the belt hole, and the chape is the plate that joins buckle to belt.

What is the pin on a belt buckle called?

The prong, also called the pin or, in America, the tongue. It passes through a hole in the belt and rests on the frame to hold the belt at that length.

What is the loop next to a belt buckle called?

A keeper, or belt loop: a loop of leather, fabric, plastic or metal that holds the tip of the belt down after it has gone through the buckle.

What are the different types of belt buckles?

Frame buckles with a prong are the oldest kind, with the bar at one end or across the center. D-rings, slide buckles and side-release buckles have no prong: the belt threads through rings or slots, or two halves snap together.