How to Measure Inside Box Dimensions | DIYpack Guide
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How to Measure
Inside Box
Dimensions

When ordering custom packaging, accurate measurements are essential. All DIYpack boxes are based on inside dimensions, which ensures your product fits perfectly without excess space or shipping waste.

In this guide, we'll show you exactly how to measure a box using the standard format Length (L) × Width (W) × Depth (D). Follow these simple steps to measure correctly and avoid common sizing mistakes.

DIYpack illustration showing how to measure inside box dimensions, labeled Length (L), Width (W), and Depth (D) with directional arrows.
Fundamentals

Understanding Box Dimension Order

Box dimensions are always listed in this order: Length (L) × Width (W) × Depth (D)

L

Length

The longest side of the box opening

W

Width

The shorter side of the box opening

D

Depth

The distance from top to bottom when the box is closed

Always measure the inside of the box — not the outside.
Instructions

Step-by-Step: How to Measure Inside Dimensions

L Measurement
1

Measure the Length

Open all top flaps and measure the longest side of the box opening from left to right.

W Measurement
2

Measure the Width

Now measure the shorter side of the box opening from front to back.

D Measurement
3

Measure the Depth

Measure from the inside bottom of the box to the top opening (where the flap creases).

Always measure in inches and round to the nearest 1/16" if needed.

Why It Matters

Why Inside Dimensions Matter

Inside dimensions determine:

  • Product fit
  • Shipping efficiency
  • Protection during transit
  • Material usage and sustainability

Measuring incorrectly can lead to:

  • → Product shifting
  • → Damaged goods
  • → Overspending on shipping

DIYpack uses inside dimensions to ensure your packaging fits your product — not just the outside footprint.

Pro Tip

Measuring Your Product First

Decide what type of box would be the best fit for your product. Before measuring a box, measure your product:

  • → Add clearance for inserts (if you are using)
  • → Allow room for protective padding like bubble wrap, tissue paper, or filler material (if needed)
  • → Add about 1/8" to each dimension

Right-sized packaging reduces waste and shipping costs.

Reference

Fractions to Decimals

FractionDecimal
1/16"0.0625"
1/8"0.125"
3/16"0.1875"
1/4"0.25"
5/16"0.3125"
3/8"0.375"
7/16"0.4375"
1/2"0.5"
9/16"0.5625"
5/8"0.625"
11/16"0.6875"
3/4"0.75"
13/16"0.8125"
7/8"0.875"
15/16"0.9375"
FAQ

Frequently Asked Questions

Box dimensions are measured in the order Length × Width × Depth (L × W × D). Always measure the inside of the box from wall to wall for accurate sizing.
Custom packaging companies like DIYpack use inside dimensions. Measuring the inside ensures your product fits properly within the box.
Length always comes first, followed by width, then depth. The correct format is Length × Width × Depth.
Measure the inside dimensions of the box and ensure your product has enough room for protective materials. Accurate measurements help reduce shipping costs and damage risk.
Inside dimensions determine how your product fits inside the box. Incorrect measurements can lead to wasted space, higher shipping costs, and product damage.
DIYpack offers instant pricing online and allows you to order a sample to test fit before placing a larger order. You can always contact us if you have any questions.
Contact us so we can help you factor in the full size of the inner box with fluting included to ensure it fits in the outer box.

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