Digital & everyday

Two-photo mat layout calculator

Fit two different-sized photos into an existing frame or calculate a new mat size. Get borders, window coordinates and a scaled preview.

Your measurements

Change any value to calculate

Switch units without changing your quantities. The formula and worked example below keep their stated units.

Enter the full physical print width, including the edges that will sit behind the mat. Use the print’s intended orientation; the tool does not rotate it.

in
in

Enter the full physical print width, including the edges that the mat will cover. Photo B keeps the orientation you enter.

in
in

Clear mat space from one cut-out window edge to the next, not center-to-center spacing. It runs horizontally side by side, or vertically when stacked. The hidden paper-edge gap is this value minus twice the overlap, so the opening gap must be at least twice the overlap.

in

Use borders to find a new mat’s outside size, or enter the measured insert size for a frame you already own. Existing-frame mode keeps both photos at their entered sizes and calculates the outer borders.

Distance from each outside mat edge to the overall group of visible windows. The narrower window is centered when photos are stacked, so its individual side borders may be wider.

in

Distance from the top of the mat to the top of the overall window group. A shorter photo is centered vertically in a side-by-side arrangement.

in

Distance below the overall window group to the mat’s bottom edge. A larger bottom than top gives a bottom-weighted layout.

in

Width of the mat board that actually fits inside your frame. Measure the required insert, not the frame’s outer width; no fit clearance is subtracted automatically.

in

Height of the mat board that actually fits inside your frame. Use a measured insert size rather than relying only on a nominal frame label.

in
Mounting adjustments OptionalOverlap on each photo edge: 0.125 in

These settings still apply when this section is closed.

Amount of the photo hidden under the mat at each edge. The visible window is smaller than the print by twice this amount in both width and height.

in

How much wider the bottom border should be than the top border. Enter zero for equal top and bottom borders; this amount is extra, not the complete bottom border.

in
Mat board cut width
13.5 in
AB
Front view · A and B are the visible openings. The line with end ticks marks the opening gap. Dashed outlines show the complete prints beneath the mat. Proportional preview; not a full-size cutting template.Visible opening gap: 1 in
Hidden paper-edge gap: 0.75 in
Why are these gaps different?

The mat covers 0.125 in of each facing print edge. Those two hidden strips use part of the visible opening gap.

1 in − 2 × 0.125 in = 0.75 in between the complete prints.

Distances run horizontally for this side-by-side layout. They are edge-to-edge, not center-to-center. No space for mounting tape or cutting tolerances is added automatically.

Mat board cut height
9.25 in
Mat board left and right borders
1.5 in
Mat board top border
1.5 in
Mat board bottom border
2 in
Opening A width
3.75 in
Opening A height
5.75 in
Opening A left coordinate
1.5 in
Opening A top coordinate
1.5 in
Opening B width
5.75 in
Opening B height
3.75 in
Opening B left coordinate
6.25 in
Opening B top coordinate
2.5 in
Hidden paper-edge gap
0.75 in

Displayed values are rounded. Whole packages and purchase lengths round up. See assumptions below.

Calculation details

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How to use this calculator

Enter both complete print sizes, the overlap on every edge and the gap between visible windows. Choose side by side or stacked. Calculate mat size from borders when ordering a new insert. For a frame you already own, choose Fit an existing frame insert and enter the measured board size that fits it, then the extra bottom border you want beyond the top. The tool derives equal side borders and the top and bottom borders while keeping both prints at their entered sizes. The smaller window is centered on the shared cross-axis. Use the preview, dimensions and coordinates to plan the cuts. In existing-frame mode, compare both arrangements and the extra width or height each needs. Switching arrangements never rotates or resizes a photo.

The formula

Each window = photo dimension − 2 × overlap. Side by side: content width = window A width + gap + window B width; content height = the taller window. Stacked: content width = the wider window; content height = window A height + gap + window B height. To calculate mat size: width = content width + 2 × side border; height = content height + top + bottom borders. For an existing insert: side = (insert width − content width) ÷ 2; top = (insert height − content height − extra bottom) ÷ 2; bottom = top + extra bottom. Every outer border must hold at least the overlap. Center the smaller window on the shared cross-axis. Coordinates are measured from the mat’s front-view top-left corner.

A worked example

A 4 × 6 inch photo and a 6 × 4 inch photo, each overlapped by 0.125 inch per edge, need 3.75 × 5.75 and 5.75 × 3.75 inch openings. Side by side with a 1 inch opening gap, 1.5 inch side and top borders, and a 2 inch bottom border, the mat is 13.5 × 9.25 inches. Opening A starts at (1.5, 1.5); B starts at (6.25, 2.5). Existing-frame example: 10 × 15 and 15 × 10 cm prints with 0.5 cm overlap, a 2 cm gap and a measured 35 × 24 cm insert have 5 cm side borders. With 2 cm extra bottom border, top is 4 cm and bottom is 6 cm; A starts at (5, 4), B at (16, 6.5). All coordinates are from the front-view top-left.

Assumptions & limitations

Exactly two rectangular prints, one mat layer and parallel edges; no rotation or photo resizing is applied automatically. The model uses physical print size, not pixels. It prevents hidden paper edges from overlapping or extending beyond the mat, but does not reserve mounting-tape space or enforce a cutter’s minimum border. Zero overlap permits a zero geometric border; this alone does not guarantee print support or practical cutting. Measure the required insert size; do not enter the frame’s outside dimensions or rely on its nominal label. No frame-fit clearance is subtracted automatically. Dimensions describe visible windows from the front, not reverse-side cut lines or bevel-cutter stops. Check your cutter’s bevel and overcut instructions and dry-fit before cutting valuable board. The preview is proportional, not a full-size cutting template.

Common questions

Can I fit two different-sized photos into a frame I already own?

Yes. Choose Fit an existing frame insert and enter the measured insert width and height. Both photo sizes stay fixed; the calculator solves the surrounding borders and rejects a layout that cannot contain the complete prints. It does not shrink or crop the photos to force a fit. The arrangement comparison shows whether stacking instead would work, and the minimum insert dimensions for both options.

Should I enter the frame’s outside dimensions?

No. Enter the actual mat board insert dimensions that fit inside the frame, measured in the chosen orientation. The outside frame size and nominal product label can differ from the insert. Measure and allow any required fit clearance before entering these dimensions.

Why does the gap differ from the distance between the paper edges?

Each hidden print edge extends by the overlap into the window gap. The physical paper-edge gap is opening gap minus twice the overlap.

What does extra bottom border mean?

It is the amount by which the bottom border exceeds the top. In existing-frame mode, zero gives equal top and bottom borders. Increasing it moves both openings upward without changing their sizes.

Is this a double mat calculator?

No. Two openings means two pictures in one mat layer. A double mat is two stacked layers and needs separate reveal and cut settings.

Supporting reference

The method above states this calculator’s assumptions. This reference provides related definitions and technical context.

Logan Graphic: planning and cutting multiple-opening mats ↗

Formula and worked example checked against automated test cases. About our methodology.

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