Calculate finished rectangular door dimensions for one horizontal row of equally wide doors covering a single opening. All doors share the same height. Enter the opening width and height, the overlay at each outside edge, the number of doors, and the equal gap between adjacent doors. For two doors this is the centre gap; for more doors it repeats at each join. For one door it has no effect.
Enter every length in metres: divide millimetres by 1,000. For example, 600 mm = 0.600 m and 2 mm = 0.002 m. Results are in metres; multiply by 1,000 for millimetres. Defaults are illustrative dimensions, not recommended hardware clearances.
The Cabinet Door Store describes adding overlays to opening dimensions and subtracting a gap before dividing a double-door width by two. See Calculating Door & Drawer Front Dimensions. Its example gap is not a clearance recommendation for this tool.
The general formula here follows directly from the width balance: n equal door widths plus n − 1 gaps must equal the opening width plus the two outside overlays. Rearranging gives the displayed width formula. Adding the top and bottom overlays gives the height. Unequal outside overlays and counts above two are geometric extensions of that balance, not hardware arrangements verified by the source.
An overlay extends a door beyond the opening edge, so it adds to the opening dimension. The left and right overlays apply only at the outside edges of the entire row, not to every door. The centre reveal is the visible gap between adjacent door edges.
Inset doors fit within the opening. With inset edge gaps rL, rR, rT and rB, the corresponding geometry is w = [W − rL − rR − (n − 1)g] / n and h = H − rT − rB. These inset formulas are included for comparison; this calculator accepts nonnegative overlays and calculates overlay doors only. Zero overlay does not create an inset clearance.
An exposed strip of face frame outside an overlay door is another kind of reveal. Calculating that strip requires frame dimensions, which this tool does not collect.
Opening width and height must each be 0.1000–10.0000 m. Each overlay must be 0–0.1000 m, and the inter-door gap must be 0–0.0100 m. Length input increments are 0.0001 m (0.1 mm). Use a whole-number door count from 1 to 10; fractional counts are not meaningful. These computational bounds ensure positive dimensions for valid inputs and are not manufacturing limits.
The model assumes a rectangular opening and one horizontal row with equal widths, equal heights and equal inter-door gaps. It does not size separate openings around intermediate stiles, stacked doors, bifold mechanisms or unequal leaves. Results are finished outside dimensions, not frame-part cut lengths or machining allowances.
Choose overlays and gaps using the actual cabinet construction and hardware documentation. This tool does not prescribe hinge clearances, movement allowances, door thickness, swing clearance or allowable door size. Display precision does not establish fabrication accuracy. An unavailable result is not zero.
| Case | Opening W × H | Overlays L / R / T / B | Door count and gap | Each door W × H |
|---|---|---|---|---|
| Default pair | 600 × 700 mm | 12 / 12 / 12 / 12 mm | 2 doors; 2 mm gap | (600 + 12 + 12 − 2) / 2 = 311 mm wide; 700 + 12 + 12 = 724 mm high |
| Single door | 450 × 600 mm | 10 / 15 / 8 / 12 mm | 1 door; gap ignored | 450 + 10 + 15 = 475 mm wide; 600 + 8 + 12 = 620 mm high |
| Three equal doors | 900 × 700 mm | 15 / 20 / 10 / 10 mm | 3 doors; two 3 mm gaps | (900 + 15 + 20 − 6) / 3 = 309.666… mm wide; 720 mm high |
Formula reference
No registered thumbnail asset was supplied. Create and register a 400 × 400 pixel WebP thumbnail, then insert it as the first image block. Match neighboring tool thumbnails: a cheerful yellow five-point star mascot with hands, no separate legs or feet, on a white background with playful navy, blue and teal graphics showing cabinet doors, outside overlays and a centre gap. No asset ID or file path is proposed until the artwork is registered.