Multi-opening mat calculator
Find the outer board for a regular grid of equal mat windows.
Choose your measurements and calculate to see the result.
A visual size estimate. Verify the actual artwork, frame, mat, glazing, hardware, wall and manufacturer specifications before buying or arranging a display. Dimensions alone do not guarantee fit.
Size the windows and the spaces between them.
This tool calculates a board for identical rectangular openings arranged in rows and columns. The inner gap is measured between window edges; the outer border runs from the outermost window to the board edge.
Board width = columns × window width + inner gaps + 2 × outer border
Worked example: four 4 × 6 photos
At ⅛ inch overlap per edge, each window is 3¾ × 5¾ inches. A 2 × 2 arrangement with 1 inch inner gaps and 2 inch outer borders needs a 12½ × 16½ inch board.
The window layout does not prove that the full prints fit independently behind the board. Their hidden borders may overlap. Confirm full sheet sizes, supplier web-width limits, backing dimensions and the actual frame opening. Use the single-window calculator to derive each opening.