Rabbet vs. Point-to-Point

RailChop Team · April 2026 · 5 min read

The Two Standards, Defined

Rabbet measurement (sometimes called "rabbet to rabbet" or "sight size") is the inside dimension of the frame. It's the opening where the glass, mat, and artwork sit — essentially the visible size of the artwork once the frame is assembled. If a customer brings in a 16×20 print, that's a 16×20 rabbet measurement.

Point-to-point is the outside dimension of the finished frame, measured from the outer corner of one rail to the outer corner of the opposite rail. It includes the moulding on both sides. For the same 16×20 artwork with a 1.5" moulding, the point-to-point measurement would be roughly 19×23.

The two numbers describe the same frame from different sides. Neither is "right" — they're just different reference points. The problem is they produce different numbers at the saw, and using the wrong one can ruin a piece of expensive moulding.

Why Shops Develop Different Habits

Rabbet measurement is the older standard and still the most common in North American framing shops. It lines up naturally with the artwork size the customer brings in. When a customer says "I have a 16×20," the rabbet is 16×20 — no conversion required. Matboards, glass, and backing boards are also sized off the rabbet dimension, so the whole package flows from one number.

Point-to-point is more common in production-oriented shops and in Europe. The logic: the customer ultimately sees the outer dimension of the finished frame. A frame quoted at "18×22" has a clearer relationship to what actually hangs on the wall than one quoted at "16×20 rabbet" (because the rabbet includes the artwork dimension, which the customer already knows).

Some shops use both, depending on who's writing the work order. That's where trouble starts.

The Math Difference

For the same frame, the two measurements are related by the moulding width. If the rabbet is W × H and the moulding width is M, then point-to-point = (W + 2M) × (H + 2M). A 16×20 rabbet with a 1.5" moulding becomes a 19×23 point-to-point. A 16×20 rabbet with a 0.75" moulding becomes a 17.5×21.5 point-to-point.

This is where mixups become expensive. If your cut ticket says "19" wide" and your saw operator assumes that's a rabbet measurement, they'll cut a frame three inches too big. On expensive gilded moulding, that's a $40 mistake. Do it twice in a week and you've paid for a year of RailChop Business.

The Formula for Each Measurement Mode

The cut length for each side of the frame depends on which measurement standard you're starting from:

Starting from rabbet: cut length = rabbet dimension + (2 × moulding width) + allowance. The moulding width gets added because each miter corner consumes the moulding depth on both sides.

Starting from point-to-point: cut length = point-to-point dimension + allowance. The moulding width is already built into the point-to-point number, so you don't add it again.

Getting these mixed up — adding 2×moulding width to a point-to-point dimension, or forgetting to add it to a rabbet dimension — is one of the most common cutting errors. The numbers look plausible. The frame doesn't.

Which Should Your Shop Use?

The honest answer: it doesn't matter which you use, as long as you use it consistently. Both are valid. Both are widely used in the industry. The disaster scenario is when a shop uses both interchangeably — sometimes quoting in rabbet, sometimes in point-to-point, without clear labeling on the work order.

A few practical considerations:

• If most of your work is custom and starts from customer-supplied artwork dimensions, rabbet is the natural choice. It removes one math step from every order.
• If most of your work is production (reproductions, gallery orders, furniture-style frames), point-to-point may match what your customer or project manager specifies.
• If you subcontract to other shops or send frames out for joining, check what they expect. Most chop-and-join services work in rabbet by default.
• If your team rotates or you hire seasonally, rabbet is easier to train because it maps to the artwork size customers bring.

How to Keep It Consistent

Pick one standard. Make it explicit on every work order and cut ticket. Label the number with "R" (rabbet) or "P2P" (point-to-point) if there's any chance of ambiguity. Train your whole team on which standard your shop uses. Don't assume everyone knows.

When you get a customer-supplied dimension that's labeled ambiguously ("16 by 20"), confirm which they mean before writing it on the work order. Most customers mean artwork size (= rabbet), but not all. A photographer might give you a matted dimension. An architect might give you a finished dimension. Ask.

RailChop supports both measurement modes at the shop setting level. You pick rabbet or point-to-point once, and the app applies it to every cut plan that follows. The optimizer math handles the conversion correctly for either mode — so whichever standard your shop uses, the dimensions hitting the saw are right. See how the optimizer handles different measurement modes.

One Last Tip: The Mat Changes the Game

If you're adding a mat to the artwork, the rabbet dimension isn't the artwork size anymore — it's the mat opening plus the mat border widths. A 16×20 artwork with a 3-inch mat has a mat outer (and therefore rabbet) of roughly 22×26. Run the mat border calculator to get the rabbet dimension for matted frames.

This is another place where mixups happen. A work order that says "16×20 with 3" mat" could mean the mat opening is 16×20 (and the rabbet is 22×26) or the rabbet is 16×20 (and the artwork is smaller). Label it. Every time. The five seconds of writing "art size" vs. "opening" vs. "rabbet" on the work order is cheaper than a redo.