Gallery Wall Planner

How to use it: enter your wall width, the width and height of each frame (frames are assumed identical), how many frames you have, and the gap you want between them. The tool sizes the whole row and centers it on the wall.

Formula. The group width is every frame side by side plus a gap between each adjacent pair (count − 1 internal gaps, none at the outer ends of the row itself); the leftover wall width is then split evenly on both sides to center the group:

groupWidth = count × frameWidth + (count − 1) × gap
sideMargin = (wallWidth − groupWidth) ÷ 2

Worked example. With the defaults above (wall 3600 mm, frame width 500 mm, count 4, gap 100 mm): groupWidth = 4×500 + 3×100 = 2000 + 300 = 2300 mm; sideMargin = (3600 − 2300) ÷ 2 = 1300 ÷ 2 = 650 mm. So the row of frames is 2300 mm wide, centered with 650 mm of clear wall on each side.

The result above uses these exact values. This snapshot is included when the page is printed so the output can be checked against the original measurements.

Wall width

3600 mm

Frame width

500 mm

Frame height

700 mm

Frame count

4

Gap between frames

100 mm

Primary result: Side margin: 650.0 mm.

• Measure from the datum or reference edge described by this tool, and do not mix inside, outside and centerline dimensions.
• Keep inputs in the displayed units and preserve more precision than the final cutting or purchasing tolerance requires.
• When the result is close to a limit, verify it with a test piece, field measurement, manufacturer drawing or qualified project professional.

This lays out a single horizontal row of identical frames only - it does not plan salon-style multi-row or staggered arrangements, and it assumes every frame shares the same outer width.

Frame height is used only to draw the preview to scale; it has no effect on the width or margin numbers, and the tool does not suggest a hanging height, eye-level centerline, or vertical offset for hanging hardware - plan the vertical position separately.

It uses each frame's outer (overall) dimensions. If you measure a frame by its opening or mat size instead of its actual outer edge, your on-wall spacing will be off - measure to the outside of the frame.