# Corrugated Box Volume Calculator

> Find the inside volume of a box in litres, cubic metres, cubic feet and cubic inches, with an approximate outside volume from board thickness.

Category: Manufacturing & packaging · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/corrugated-box-volume-calculator

A box’s capacity is inside length × width × height. Adding the board thickness to each side gives an approximate outside volume for shipping and storage.

Also called: Carton volume calculator, Box cubic feet calculator.

## Inputs
- Dimensions in (options: mm, cm, inches; default mm)
- Inside length (default 400)
- Inside width (default 300)
- Inside height (default 250)
- Board thickness (default 4; optional)

## Results
- Inside volume
- Inside volume
- Inside volume
- Inside volume
- Approximate outside volume

## Formula

```
Inside volume = L × W × H;  Outside ≈ (L + 2t) × (W + 2t) × (H + 2t)
```

Where:
- L, W, H: inside dimensions
- t: board thickness
- 1 ft³: 28.316846592 L (exact)

## Worked example
1. Inside = 400 × 300 × 250 = 30,000,000 mm³ = 30 L = 0.03 m³.
2. 0.03 m³ ÷ 0.0283168 m³/ft³ = 1.0594 ft³.
3. Outside ≈ 408 × 308 × 258 mm = 32.42 L.

**Result:** A 400 × 300 × 250 mm box holds 30 litres (1.06 ft³) and takes up about 32.4 litres from the outside.

## What the result means

Use inside volume to check product fit and fill; use the outside volume for pallet and container planning.

## Assumptions and limits
- The box is a rectangular prism.
- The outside volume is approximate: RSC flaps overlap, so the real outside height can be a little more than inside height plus two thicknesses.

## Questions

### Is the outside volume used for courier charges?

Couriers measure the outside, so measure the real box or use the approximate outside size with the dimensional weight calculator.

### How do I convert litres to cubic feet?

Divide litres by 28.3168.

## Related calculators
- [Corrugated Box Board Area Calculator](https://calculators.geekmidst.com/calculators/corrugated-box-board-area-calculator)
- [Packaging Dimensional Weight Calculator](https://calculators.geekmidst.com/calculators/packaging-dimensional-weight-calculator)
- [Case Pack Optimization Calculator](https://calculators.geekmidst.com/calculators/case-pack-calculator)
- [Length Converter](https://calculators.geekmidst.com/calculators/length-converter)

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/corrugated-box-volume-calculator