Finding the right cardboard box isn’t always as easy as it sounds. You may measure your product, order a box that appears big enough, then find that there’s barely any room left for protecting your goods. Or maybe the box is much too big for you and all your items move around inside.
It’s a problem that plagues many online sellers and businesses who regularly ship products. Good news, it requires only a few minutes of your time to make the necessary measurements.
You may be packing items for customers, moving house, or storing away, but knowing the dimensions of cardboard boxes can help you choose the right kind of packaging.
How Do You Measure a Cardboard Box?
Most cardboard boxes are measured in this order: length width height (L W H). It’s easy to calculate, but always check the specifications of your supplier before making your purchase.
Here’s a quick overview:
- Length: Usually the longest side of the box opening.
- Width: The narrower side of the opening.
- Height: Distance between the bottom and top of the structure.
One thing people may overlook is the difference between internal and external dimensions of a box. The inside dimensions are how much space there is inside the box, and the outside measurements are the thickness of the cardboard.
If you’re packing a product, the internal dimensions are most important. After all, you need room for the product and any protective material that might be around it. But, if you’re packing it in a cupboard, storage unit or vehicle, remember to check the external dimensions too.
What Are the Standard Cardboard Box Sizes?
There isn’t one fixed size for every cardboard box. Different products need different amounts of space, so packaging suppliers offer a range of dimensions to suit everyday requirements.
The table below gives you an idea of the sizes you might come across.
| Box type | Example dimensions (L × W × H) | Suitable for |
| Small | 20 × 15 × 10 cm | Accessories, cosmetics and small parts |
| Medium | 30 × 20 × 15 cm | Books, clothing and retail orders |
| Large | 45 × 30 × 30 cm | Household items and product bundles |
| Extra large | 60 × 45 × 45 cm | Bulky, lightweight products |
These dimensions are examples and not official sizes. Depending on your supplier and box type you are looking for, you may be able to find the size you require.
Before you place an order, make sure that your item is of the correct shape and weight. What box works great for clothing might not fit for fragile glassware or heavy equipment.
Cardboard Box Dimensions in Inches and CM
Cardboard box sizes may be listed in inches or centimetres. In the UK, we measure products in centimetres, although it’s not uncommon to come across box sizes in inches when shopping for different wrapping options.
Convert between the two is as easy as one inch equals 2.54 cm.
Example: a box 12 9 6 inches is 30.48 22.86 15.24 cm.
Try to measure in the same unit throughout. Changing units mid-measurement can cause miscalculations, especially if you’re measuring boxes in several sizes.
Also, make sure your box is measuring correctly before you check your order. If you make a mistake now, there’s no need to worry about getting another box later on.
Choosing the Right Box Size for Your Products
The best box depends on what you want to pack and how it needs to travel. Here are the most common options.
Small Cardboard Boxes
Small cardboard boxes are handy for delivering jewellery, electronic goods, cosmetics and spare parts. They’re convenient to pack and can be used to save on packing space when sending small items.
For delicate products, leave extra room for cushioning. Bubble wrap, a small sheet of paper or a little insert can make all the difference when your package is handled during delivery.
Medium Cardboard Boxes
The ‘medium boxes’ are useful for books, clothes, household goods and many online orders. They’re also handy for consigning a number of smaller items in one parcel.
Make sure you pack everything in a way that will not knock into each other. If you pack multiple items, dividers or individual packing may help you pack them together.
Large Cardboard Boxes
Large boxes are ideal for bulky products, bedding, light household goods and bigger orders.
But, bigger is not always better. Too much empty space might allow the boxes to shift, while too much load may put extra pressure on the box’s bottom. A corrugated box and a strong box will do just as well.
How to Calculate the Correct Box Dimensions
Start by measuring the longest, widest and tallest points of your product. If your product has an unusual shape, you may want to use the maximum measurements on your product rather than an estimate.
Next, consider any protective packaging you need.
For example, if your product is 25 15 10 cm. If you want 2 cm of cushioning on both sides, you’ll need approximately 29 19 14 cm of box space.
This is a good guide to use, but the final size will depend on the thickness of the cushioning and how the product sits in the box.
If you’re ordering boxes for a company, it may be wise to order a sample before placing a large order. You can test the fit, the packing process and overall protection before ordering a full batch.
How Box Dimensions Can Affect Shipping Costs
Size of your package can have a bearing on the delivery costs for light items.
Some UK courier companies use volumetric weight to measure the space that a parcel occupies during transport, so a heavy parcel may be heavier than it actually is.
Oversized parcels may also be subject to extra charges or be refused a delivery service entirely. These fees vary between couriers, so make sure you check for your options before you book.
Choosing a box that fits your product properly can help save on space and shipping cost without sacrificing protection.
When Should You Consider Custom Cardboard Boxes?
Although standard sizes are good for most regular packaging needs, some products do not fit in a typical off-the-shelf box.
Custom cardboard boxes let you pick the size that matches your products. You can also customize your boxes with inserts, dividers or other features that provide more security.
For businesses, it can make packing more straightforward and products look neater when they get to the customer. A good-fitted box may also mean that there is less space required to fill voids.
Staysure Packaging is one brand to consider when thinking of packaging for your business. Check out the quality of cardboard, size options, printing options, quantity discounts and delivery costs before choosing a supplier.
Common Box Sizing Mistakes to Watch Out For
The most common omissions cause bigger problems when made later. One of the most common is to not properly measure the inside and out of the box. Another is to not account for the size of bubble wrap, foam inserts or packing paper.
It is easy to make a box choice just by its size label without checking the actual dimensions. Bear in mind that two boxes labelled medium may be very different in dimensions.
Don’t forget to check the weight of your products or the size restrictions for your courier before you place your order so you don’t incur unnecessary costs and problems with packaging.
Conclusion
Choose the correct cardboard box dimensions by measuring and planning how your products will be packed, stored and delivered.
Check the length, width and height, check whether the dimensions are internal or external, and allow plenty of room for wrapping. Check whether the cardboard is strong enough and your courier will need it.
With a little planning, you will find some packaging that will fit perfectly, protect your products and make packing much easier.