How it works
For n compartments, use d = n − 1 dividers. Clear width g = (internal width W − d × divider thickness t) ÷ n. For divider i: left edge = i × g + (i − 1) × t; centerline = left edge + t ÷ 2; right edge = left edge + t.
Calculator
Drawer Divider Spacing Calculator
Subtract divider thickness before spacing equal compartments. Get each divider’s left edge, centerline and right edge from one origin in millimeters.
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Results update as you type · Prefilled values are a worked example
120.5mm clear width per compartment
4 compartments; dividers required: 3 dividers
Measure from the internal left edge at 0 mm; colored blocks are dividers
| Divider | Left edge | Centerline | Right edge |
|---|---|---|---|
| 1 | 120.5 | 123.5 | 126.5 |
| 2 | 247 | 250 | 253 |
| 3 | 373.5 | 376.5 | 379.5 |
Positions use full precision from one origin. Do not accumulate rounded compartment widths. Joint and machining allowances are excluded.
Scope & limitations
Every position uses full precision from one common origin. Do not add rounded compartment widths repeatedly, which accumulates error. Measure actual internal width and board thickness. The range is 1–500 parallel compartments. Extra frames, grooves, glue joints and machining allowances are separate. This is a storage-layout calculator, not structural, load-bearing, railing-code or machinery advice.