Shop Reference · Mat Cutting

Mat Cut Calculator

for single-window mats with independent borders
01 · Outer mat dimensions
Usually matches the frame’s rabbet opening.
02 · Borders (per side)
Bottom-weighted (slightly larger bottom border) reads better on vertical art.
03 · Artwork & best fit
Use whole board as outer, center the artwork, and bottom-weight the top/bottom split for optical center.
Would set borders to 3″ T · 3 1/2″ B · 2 3/4″ L · 2 3/4″ R
Window Opening · short point to short point
Width
10 1/2"
Height
13 1/2"
Mat Layout
16"OUTER WIDTH20"OUTER HEIGHT3"3 1/2"2 3/4"2 3/4"WINDOW10 1/2" × 13 1/2"
Cutter Guide-Bar Settings
Cut 01 · Top window edge
Guide bar offset3"
Plunge at2 3/4"
Stop at13 1/4"
Face down · top edge against guide bar
Cut 02 · Bottom window edge
Guide bar offset3 1/2"
Plunge at2 3/4"
Stop at13 1/4"
Face down · bottom edge against guide bar
Cut 03 · Left window edge
Guide bar offset2 3/4"
Plunge at3"
Stop at16 1/2"
Face down · left edge against guide bar
Cut 04 · Right window edge
Guide bar offset2 3/4"
Plunge at3"
Stop at16 1/2"
Face down · right edge against guide bar
All Dimensions
Outer mat
16" × 20"
matches frame rabbet
Window (sight opening)
10 1/2" × 13 1/2"
cut from the face side, short point to short point
Borders
3" top · 3 1/2" bot · 2 3/4" L · 2 3/4" R
distance from outer edge to window edge
Artwork
11" × 14"
as specified
Actual reveal
1/4" L/R · 1/4" T/B
mat coverage onto the artwork edge
Notes
  • Cut the mat face down. Guide-bar offset is the border for the edge you set against the bar.
  • Plunge and stop positions are measured along the cut, from the perpendicular outer edge.
  • For a beveled cutter, overshoot each plunge/stop slightly to account for the bevel reach — verify on a scrap first.
  • Inputs accept decimals like 1.5, or fractions like 1 1/2 or 1/4.
  • Reveal (overlap onto artwork) is typically 1/8″ to 1/4″ per side so the mat hides the paper edge.