Box Size Calculator
Find a practical internal box size for your products, with padding, arrangement controls, and estimated external dimensions.
Free to use · Calculated in your browserYour packing numbers
2 items shown at 2 cm. Only items starting at this height are shown; taller items from lower levels are hidden. Verify real loading constraints.
How this result was calculated
- Grid = 1 × 2 × 3 positions, holding 6 products.
- Each internal axis = product size × count + clearance × (count − 1) + 2 × outer padding.
- Each external axis = internal axis + 2 × board thickness.
- Internal volume = 0.02898 m³; external volume × 1,000,000 ÷ 5,000 = 6.148 kg dimensional weight.
Detailed breakdown
| Axis | Oriented product (cm) | Grid count | Internal (cm) | External (cm) |
|---|---|---|---|---|
| Length | 20 | 1 | 24 | 24.6 |
| Width | 15 | 2 | 34.5 | 35.1 |
| Height | 10 | 3 | 35 | 35.6 |
The compact option searches uniform grids up to 200 positions on each horizontal axis and favors lower external surface area. Mixed orientations and bespoke structural designs may fit better.
External dimensions use a simple two-wall allowance. Flaps, scoring, compression, closures and manufacturing tolerances can change finished size. Confirm with the box manufacturer.
The preview shows 6 of 6 products inside the internal dimensions. Padding is the empty space at the outside edge.
This is a dimensional estimate, not a strength, crush-resistance or protective-performance assessment.
How to use this tool
For each axis, internal dimension = grid count × oriented product dimension + (grid count − 1) × product gap + 2 × outer padding. Estimated external dimension = internal dimension + 2 × board thickness. External volume and the selected dimensional divisor give estimated dimensional weight.
A worked example
For one 20 × 15 × 10 cm product with 2 cm padding on every side and no extra clearance, the required internal size is 24 × 19 × 14 cm. With a simple 3 mm wall model, estimated outside dimensions are 24.6 × 19.6 × 14.6 cm.
Put the result to work
Allowances are dimensional estimates. Protective performance depends on the product, cushioning, board grade, inserts, closure, and distribution environment. Test a physical sample; internal dimensions and the largest closed external dimensions serve different purposes.
Read the complete guideCommon questions
Should I enter product or shipping dimensions?
Enter the product dimensions here. The tool adds the selected allowances to estimate a box. Enter finished external carton dimensions in the CBM and dimensional weight tools.
Is padding added to both sides?
Padding on every side adds twice the chosen padding to each enclosing dimension. Check the separate clearance setting and the displayed arrangement.
Can this specify a production-ready carton?
It can help choose a size. Board performance, score allowances, manufacturing tolerances, and protective testing still need a packaging supplier's review.