Gemsmakers · Furniture measurement bench

Antique Furniture Drawer Box Clearance Calculator

Compare the measured opening in a chest, desk or cabinet with a proposed drawer box. Record side, top and depth allowances separately, account for a chosen slide method, and build a repeatable schedule for a furniture conservator or cabinetmaker.

Imperial or metricMultiple drawer scheduleLocal export · no upload

Opening and proposed box

Measure the clear opening at its narrowest practical point. The calculator compares dimensions only; it does not specify joinery, runner repairs or a conservation treatment.

Object / drawer referenceUnitsClear opening widthProposed box outside widthOpening heightProposed box outside heightUsable opening depthProposed box depthSlide / runner arrangementAdditional total side allowanceClearance beyond box width, total both sides (planning value only).Top allowanceOpening height minus box height.Rear allowanceOpening depth minus box depth; account for stops and back geometry.Measurement method, runner condition and assumptions

Fit comparison

Enter positive opening and box dimensions

Results appear as soon as the required measurements are entered.

Side allowance remaining
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Top allowance remaining
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Rear allowance remaining
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Width difference
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Drawer measurement schedule

Schedule stays in this page session. Download a CSV before closing if you need a durable workshop record.

Reference	Opening (W × H × D)	Box (W × H × D)	Margins (side / top / rear)	Fit note
No measurements added yet.

Measure before sizing

Record the furniture ID and drawer location; avoid relying on labels alone.
Measure the opening at front, middle and rear, side to side and vertically. Enter the tightest usable clear envelope.
Check the box travel path and the position of stops, web frames, dust boards and rear structure.
Measure existing runners and guides without removing historic material.
Record whether dimensions describe the existing drawer, a proposed replacement or a conservation mock-up.

An opening can be tapered, racked or locally worn. One dimension may not represent its whole travel path.

Interpreting the result

Remaining side margin is opening width minus box width and the additional total allowance you entered. A negative result signals a dimensional conflict under those assumptions. Positive margin does not guarantee smooth travel or structural compatibility.

For side-mounted slides, confirm the specific hardware maker’s required side clearance and installation geometry. Traditional wood-on-wood drawers respond to wear, finish build-up, seasonal movement, runner shape and load. This planner cannot infer those conditions from measurements.

Use consistent units and distinguish a measured opening from a target box size. Have a qualified furniture conservator or cabinetmaker assess historic runners, repairs and any proposed alteration.

Drawer sizing questions

Does a positive margin mean the drawer will fit?

No. It only means the arithmetic is non-negative for the dimensions entered. Check squareness, runner geometry, travel, hardware requirements and any local obstruction.

Why enter total side allowance?

The input is a combined left-plus-right allowance. The calculator subtracts that amount from the width available to the box, so you can record the hardware or workshop assumption without assigning it to each side.

Can this recommend a clearance for antique furniture?

No. Existing material, movement, wear and construction differ. Use measurements as a documented comparison and obtain professional advice before making or altering a drawer.