Box Size Calculator
Work out the right box size for your product. Enter its length, width and height, choose how much clearance to leave, and get the recommended internal box dimensions, an estimate of the external size and the internal volume, in millimeters, centimeters or inches.
- Internal and estimated external dimensions
- Clearance and insert allowances kept separate
- Free, no sign-up, nothing leaves your browser
Your box dimensions
Recommended internal dimensions L × W × H
160 × 110 × 90 mm
6.299 × 4.331 × 3.543 inEstimated external dimensions Estimate
163.2 × 113.2 × 93.2 mm
6.425 × 4.457 × 3.669 inSimplified estimate: board layers added L +2, W +2, H +2 layers × 1.6 mm- Product
- 150 × 100 × 80 mm
- Clearance
- 5 mm per side (adds 10 mm to each dimension)
- Internal volume
- 1.584 L (1,584,000 mm³ · 1,584 cm³ · 96.66 in³)
- External volume (estimate)
- 1.722 L (1,721,799 mm³ · 1,721.8 cm³ · 105.07 in³)
Assumptions
- Your product is treated as a rectangular block using its largest length, width and height.
- Board: Corrugated E-flute, 1.6 mm (illustrative thickness, confirm before production).
- External size adds L +2, W +2, H +2 layers × 1.6 mm. Score allowances, glue seams, lid fit gaps and wrap paper are not included.
Box preview
Drag or use the arrow keys to rotate. Not to scale with the page; proportions are exact.
Use your measurements
Request a quote opens BoxNovo's quote form and copies your specification so you can paste it into the Packaging Specifications field. Nothing is sent until you submit that form yourself.
View the full specification
BoxNovo Box Size Calculator Product dimensions: 150 × 100 × 80 mm (L × W × H) Insert or cushioning: none Clearance: 5 mm per side (adds 10 mm to each dimension) Recommended internal dimensions: 160 × 110 × 90 mm Internal volume: 1.584 L (1,584,000 mm³ · 1,584 cm³ · 96.66 in³) Construction: Simplified estimate Board: Corrugated E-flute, 1.6 mm (illustrative thickness) Estimated external dimensions: 163.2 × 113.2 × 93.2 mm, board layers added L +2, W +2, H +2 layers × 1.6 mm Important: External dimensions are estimates from a simplified board-layer model. Final production dimensions must be confirmed by BoxNovo. Calculated with https://boxnovo.com/tools/box-size-calculator/
Internal
How the box size calculator works
The calculator treats your product as a rectangular block and builds the box outward from it, one layer at a time:
- Packed size = product + 2 × insert or cushioning thickness
- Internal size = packed size + 2 × clearance per side
- Rounded internal size (optional) = internal size rounded up to the step you choose
- Estimated external size = internal size + board layers × board thickness
- Internal volume = internal length × width × height
Each formula is applied separately to length, width and height. Calculations run in millimeters at full precision and are only rounded for display, so switching units never changes the result.
Assumptions and limits
- The product is measured at its largest point on each side, as if it were a rectangular block.
- The external size is an estimate. It adds whole board thicknesses only, and leaves out score allowances, glue seams, lid fit gaps, wrap paper and production tolerances.
- Board thicknesses are illustrative nominal values. Real caliper varies by mill, flute and humidity.
- Inputs are limited to 0.1–5,000 mm per product side, up to 100 mm of clearance or cushioning per side, and 0.1–25 mm board thickness.
- Results are a planning guide, not a manufacturing specification. BoxNovo confirms final dimensions before production.
How much clearance to add
Clearance is the free space between your product and the inside of the box. It is added to both sides, so the box grows by twice the clearance in each direction. The presets are illustrative starting points, not engineering rules: fragile, heavy or high-value products may need tested cushioning rather than more empty space.
| Preset | Per side | Added to each dimension | Typical use |
|---|---|---|---|
| Exact fit | 0 mm (0 in) | 0 mm | Nominal fit with no free space. Only for products with tight, known tolerances. |
| Tight | 3 mm (0.118 in) | 6 mm | Snug fit for rigid products that must not move, such as cartons for bottles or jars. |
| General | 5 mm (0.197 in) | 10 mm | A common starting point that leaves room for measuring and production tolerances. |
| Extra | 10 mm (0.394 in) | 20 mm | Easier packing, wrapping material or slightly irregular products. |
| Generous | 15 mm (0.591 in) | 30 mm | Bulky wrapping, hand packing or products with soft or uneven shapes. |
Worked examples
A product with general clearance
A 150 × 100 × 80 mm product with the General preset of 5 mm per side.
- Product
- 150 × 100 × 80 mm
- Clearance
- 5 mm per side
- Internal size
- 160 × 110 × 90 mm
- Internal volume
- 1.584 L (1,584,000 mm³)
- Estimated external
- 163.2 × 113.2 × 93.2 mm with Corrugated E-flute at 1.6 mm
Simplified estimate: adds 2 / 2 / 2 board layers to L / W / H.
Measuring in inches
A 6 × 4 × 3 in product in a folding carton with 1/8 in clearance per side.
- Product
- 6 × 4 × 3 in
- Clearance
- 1/8 in per side
- Internal size
- 6.25 × 4.25 × 3.25 in (6 1/4 × 4 1/4 × 3 1/4 in)
- Internal volume
- 1.415 L (1,414,665 mm³)
- Estimated external
- 6.285 × 4.285 × 3.321 in with Folding carton board at 0.45 mm
Folding carton (tuck end): adds 2 / 2 / 4 board layers to L / W / H.
A fragile item with an insert
A 200 × 150 × 100 mm product wrapped in a 10 mm insert, with 3 mm clearance, in a B-flute shipping box.
- Product
- 200 × 150 × 100 mm
- Clearance
- 3 mm per side
- Insert or cushioning
- 10 mm per side → 220 × 170 × 120 mm
- Internal size
- 226 × 176 × 126 mm
- Internal volume
- 5.012 L (5,011,776 mm³)
- Estimated external
- 232 × 182 × 138 mm with Corrugated B-flute at 3 mm
Corrugated shipping box (RSC): adds 2 / 2 / 4 board layers to L / W / H.
Internal vs external box dimensions
Internal dimensions
The usable space inside the box. Custom boxes are normally specified by internal dimensions, because that is what decides whether your product fits. Use the internal size when you request a quote.
External dimensions
The size of the outside of the box: internal size plus the board walls, flaps and lid. Use it to plan shipping cartons, shelf space, pallet loads and courier size limits. Thicker board and double-wall constructions make the difference larger.
How to measure your product
- Measure the final packed product. Include caps, pumps, handles and any inner packaging such as a pouch or a bottle sleeve.
- Measure the largest point. For each side, measure across the widest part. For round or irregular products, measure the smallest rectangular block that encloses them.
- Use a rigid ruler or calipers. Measuring tapes can bend around curves and add error. Measure twice and take the larger value.
- Decide the packing orientation. Enter the dimensions in the position the product will sit in the box, with the opening at the top.
- Measure several samples if your products vary, and calculate from the largest.
Board and construction guidance
The external estimate depends on the board you choose and how the box is built. The thicknesses below are typical published nominal values used for planning only. Ask BoxNovo for the caliper of the exact board you order.
| Board | Illustrative thickness | Learn more |
|---|---|---|
| Folding carton board (SBS or kraft) | 0.45 mm (0.0177 in) | Cardboard packaging |
| Corrugated E-flute | 1.6 mm (0.063 in) | Corrugated packaging |
| Corrugated B-flute | 3 mm (0.1181 in) | Corrugated packaging |
| Corrugated C-flute | 4 mm (0.1575 in) | Corrugated packaging |
| Corrugated BC double wall | 6.5 mm (0.2559 in) | Corrugated packaging |
| Rigid chipboard (greyboard) | 2 mm (0.0787 in) | Rigid packaging |
| Construction | Layers added (L / W / H) | Basis |
|---|---|---|
| Simplified estimate | 2 / 2 / 2 | One board layer on each of the six sides. Default board: Corrugated E-flute. |
| Corrugated shipping box (RSC) | 2 / 2 / 4 | One wall layer at each end and side; top and bottom each have inner and outer flaps (two layers). Default board: Corrugated B-flute. |
| Folding carton (tuck end) | 2 / 2 / 4 | One wall layer on each side; top and bottom each have a closure panel over dust flaps (two layers). Default board: Folding carton board (SBS or kraft). |
| Mailer box (roll end tuck front) | 4 / 3 / 2 | Rolled double walls at both ends of the length; double front wall and single back wall; single base and lid. Default board: Corrugated E-flute. |
| Rigid two-piece box (lift-off lid) | 4 / 4 / 2 | Base wall plus lid wall on each side; base board below and lid board on top. Default board: Rigid chipboard (greyboard). |
Plan the rest of your packaging
- Custom boxesBrowse every BoxNovo box type.
- Box stylesCompare tuck, sleeve, gable, display and handle structures.
- Custom corrugated boxesBranded shipping and fulfillment boxes.
- Custom mailer boxesSelf-locking boxes for ecommerce delivery.
- Reverse tuck end boxesLightweight retail cartons.
- Rigid boxesPremium gift and presentation boxes.
- 3D packaging design & mockup generatorDesign your box in 3D with your logo.
- Contact BoxNovoRequest a custom quote.
Box size calculator FAQ
What is the difference between internal and external box dimensions?
Internal dimensions measure the space inside the box, where your product goes. External dimensions measure the outside, including the board walls and flaps. Custom boxes are usually ordered by internal size, while the external size matters for shipping and storage.
How much clearance should I leave around my product?
For many rigid products, 3–5 mm per side is a common starting point. Use more for hand packing, wrapping or uneven shapes, and use an insert or cushioning for fragile items. Clearance is added on both sides, so 5 mm per side makes each dimension 10 mm larger.
In what order are box dimensions written?
Length × width × height. With the box opening at the top, length is the longer side of the opening, width is the shorter side and height is the depth.
Why is the external size only an estimate?
The calculator adds whole board thicknesses using a simplified model of each construction. Real boxes also have score allowances, glue seams, lid fit gaps and production tolerances that depend on the exact dieline, so BoxNovo confirms the final external size.
Should cushioning be included in the clearance?
No. Enter the insert or cushioning thickness in its own field. It is added to the product first, then the clearance is added around it, so nothing is counted twice.
What board thickness does the calculator use?
Each board option uses an illustrative nominal thickness, for example 1.6 mm for E-flute and 3 mm for B-flute corrugated. You can type your own value if you know the caliper of your board.
Can I use inches or centimeters?
Yes. Choose millimeters, centimeters or inches. In inches you can type decimals or fractions such as 5 1/2, and the results show the nearest 1/16 inch as well.
How do I measure a round or irregular product?
Measure the smallest rectangular block that would enclose it: the widest point in each direction. Then add clearance or an insert to stop it moving inside the box.
Can the calculator round sizes for ordering?
Yes. Choose a rounding step such as the next 1 mm, 5 mm or 1/8 inch. Sizes are always rounded up, so the box never ends up smaller than the calculated internal space.
How do I order a box in the size I calculated?
Select Request a quote. Your specification is copied so you can paste it into BoxNovo's quote form. Your measurements stay in your browser: the calculator does not save or send them anywhere until you submit the form.