A clear plan
for your artwork.
Work out the opening, check visible details, and take clear measurements to your framer.
Know the paper.
Plan the opening.
“Mat size” can mean different things on different order forms. Name the physical paper, the visible opening and the outside board separately.
Paper
The actual sheet, edge to edge. Measure the printed image and important marks separately.
Window
The opening that shows the art. Its size depends on how much paper is covered at each edge.
Mat outside
The full board that fits inside the frame. This is different from the decorative frame’s outside size.
The frame’s outside size is a different measurement. Confirm the actual component space, clearance and full stack depth before purchase.
An 8 × 10 example,
from paper to window.
Suppose an 8 × 10-inch sheet is covered by 1/8 inch on every edge. Subtract both opposite edges: 8 − 1/8 − 1/8 = 7 3/4 inches across. Do the same for height.
- Paper
- 8 × 10 in
- Coverage per edge
- 1/8 in
- Exact window
- 7 3/4 × 9 3/4 in
- Mat outside
- 11 × 14 in
- Left / right border
- 1 5/8 in each
- Top / bottom border
- 2 1/8 in each
Worked example, not a universal overlap recommendation. A border runs from window to board edge; coverage is the paper hidden at the opening.
Before you order.
Measure the actual paper.
Record the physical sheet, intended orientation and unit. If there is a white border, measure the image separately. A nominal print size is not a measurement of your own piece.
Check the details near the edge.
Include signatures, titles and edition numbers in the area you want to keep visible. A mathematically fitting window can still hide a detail.
Confirm the supplier’s size language.
Ask whether the form takes art size with an automatic deduction or the exact window. Confirm the final cut, outside size, frame depth and mounting before purchase.
One rectangular opening for flat paper. These tools do not certify cutting tolerances, frame fit, mounting or preservation safety. Zero coverage in a drawing is not a method of holding the paper.
Sources & scope
Checked November 6, 2026. Supplier policies are examples of that supplier’s wording, not universal specifications. Geometry and worked examples are our own derivations; see method and limits.