Lumbertool Calculate board feet

Drawer box fit and cut list

Prepare sides and front/back pieces after selecting the actual slide clearances.

Try the calculation

Example inputs · U.S. customary units

A drawer for a 21 in opening. Confirm side clearance with the actual slide instructions and check the declared box construction.

Example: 21 in.

Example: 0.5 in. Use your selected slide instructions. The example is not a universal clearance.

Example: 18 in.

Example: 5 in.

Example: 0.5 in.

Results

Ready to calculate

Enter your values, then choose Calculate. Your results will appear here.

How to use drawer box fit and cut list

What this calculation does

This drawer model fits front and back pieces between two full-depth sides after the selected slide clearance is deducted from the opening.

Measure the opening, use the actual slide clearance for each side, then enter outside depth, height and side thickness.

Enter the measurements

  1. Opening width: Measure the clear cabinet opening.
  2. Slide clearance on each side: Enter clearance required on each side by the slide.
  3. Drawer outside depth: Choose the drawer outside depth.
  4. Drawer outside height: Choose the drawer outside height.
  5. Actual side thickness: Measure actual drawer-side thickness.

Formula and variables

Outside width = opening width − 2 × per-side clearance. Front/back length = outside width − 2 × actual side thickness. Sides run the full outside depth; all four pieces use the chosen outside height.

Outside width subtracts twice the per-side clearance. Front/back length then subtracts two side thicknesses; side length remains the entered outside depth.

Read the result

A 21 in opening with 0.5 in clearance on each side gives a 20 in drawer. Front and back are 19 in long; sides are 18 in.

Worked example

Inputs: 21 in opening, 0.5 in clearance per side, 18 in outside depth, 5 in height and 0.5 in sides

  1. Outside width = 21−2×0.5 = 20 in.
  2. Front/back = 20−2×0.5 = 19 in; each side is 18 in deep.

Expected result: 20 in outside width; front/back 19 × 5 in; sides 18 × 5 in

Frequently asked questions

Is 0.5 in a universal slide clearance?

No. Use the clearance for the actual slide and cabinet construction.

Does this include a drawer bottom?

No. Bottom grooves, setbacks, notches and hardware-specific details are not in this four-wall list.

Conditions, presets and technical notes

This model fits the front and back between two full-depth sides. It does not describe every rabbet, dovetail or undermount drawer. Bottom grooves, bottom recess, slide length, mounting setback and notches require a hardware-specific drawing and are not included in this four-piece list.