Storage Box Calculator
Buying too few storage boxes means a second trip to the shop, while buying too many wastes money and space. Estimate the total volume of what you're packing away and choose your preferred box size below to see how many you need.
Work out how many storage boxes you need
Estimate the total volume of what you're packing away (a rough guide: a standard house move box holds about 50-60L) and choose your box size.
To store 300L of belongings in 55L boxes, you'll need approximately:
7 boxes
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A few well-reviewed storage boxes for home organisation.
£24.99
Pros
- Crystal-clear sides for spotting contents
- Stacks securely with the 20/33/50/84L Really Useful range
- Lockable blue clip handles stop lids popping off
Cons
- Lid clips can feel stiff when new
- Plastic
- 40L (Pack of 2)
Currently unavailable
Pros
- Low profile (19cm) slides under most bed frames
- Removable castor wheels make it easy to pull out
- Sold as a pack of 2 for good value
Cons
- Wheels are not lockable
- Fabric
- 40 x 25 x 30cm Per Box
Currently unavailable
Pros
- Collapses flat when not in use
- Front label holders make contents easy to find
- Stitched handles for easy carrying
Cons
- Not waterproof, so unsuitable for damp areas
- Each cube rated to 3kg, so not for heavy items
Frequently asked questions
How do I estimate the volume of what I need to store?
If you're not sure, a good starting point is to count how many standard house-move boxes (around 50-60L each) your belongings would currently fill, then multiply by that figure. Alternatively, measure a rough stack of items directly using length × width × height in litres.
Is it better to use fewer large boxes or more small ones?
Larger boxes hold more but get heavy and awkward quickly, especially with dense items like books. Smaller boxes are easier to carry and stack neatly on shelving, so many people use large boxes for lightweight bulky items (bedding, soft toys) and smaller boxes for anything heavy.
Should I leave extra room in each box?
Yes — this calculator adds a little headroom to the volume estimate since irregularly shaped items rarely pack together as efficiently as a perfect cube. Leaving a bit of slack also makes lids easier to close and boxes easier to stack.
Are clear plastic boxes better than cardboard for long-term storage?
Clear plastic boxes are more resistant to damp, pests and crushing than cardboard, and let you see the contents without opening the lid — worth the extra cost for a loft, garage or shed where conditions vary more than an airing cupboard.
How this calculator works
The calculator takes the total volume you need to store (in litres) and divides it by the capacity of your chosen box size, then adds a 15% headroom allowance. The headroom accounts for irregularly shaped items that don't pack perfectly flat, and makes it easier to close the lids and stack the boxes. The result is rounded up to the nearest whole box.
Standard box sizes are 35L (small, easy to carry), 55L (medium, general use), 80L (large, bulky items) and 110L (extra large, duvets and bedding). A 55L box is roughly the size of a standard house-move box — it's a good all-rounder for most household items. For heavy items like books, use smaller 35L boxes to keep them light enough to carry. For lightweight bulky items like bedding and soft toys, use larger 80L or 110L boxes.
Storage box sizes and what they suit
| Box size | Dimensions (approx) | Weight when full | Best for | Typical contents |
|---|---|---|---|---|
| 35L | 40 x 30 x 30cm | 10-15kg | Heavy items, books, tools | Books, tools, hardware, canned food |
| 55L | 50 x 35 x 35cm | 15-20kg | General household, house moves | Clothes, kitchenware, toys, media |
| 80L | 60 x 40 x 35cm | 20-25kg | Bulky lightweight items | Bedding, cushions, soft toys, clothes |
| 110L | 70 x 45 x 40cm | 25-30kg | Very bulky, lightweight items | Duvets, pillows, winter coats, blankets |
Worked example: Packing a 3-bedroom house
A typical 3-bedroom house might have 300-400L of belongings to store or move. Using 55L boxes, the calculator estimates 300 × 1.15 ÷ 55 = 6.27, rounded up to 7 boxes for 300L, or 400 × 1.15 ÷ 55 = 8.36, rounded up to 9 boxes for 400L. In practice, you'd probably need 10-15 boxes to allow for awkwardly shaped items and separate packing for fragile things.
If you're using a mix of box sizes, calculate each separately. For example, 100L of books in 35L boxes needs 100 × 1.15 ÷ 35 = 3.29, rounded up to 4 boxes. 200L of bedding in 80L boxes needs 200 × 1.15 ÷ 80 = 2.875, rounded up to 3 boxes. Total: 7 boxes. This mix gives you manageable weights for the heavy books and efficient packing for the bulky bedding.
Common mistakes when buying storage boxes
- Buying boxes that are too large for the space they'll be stored in. A 110L box might seem like a good idea for duvets, but if it needs to fit on a shelf in the loft or under a bed, check the dimensions first. A 110L box is typically 70cm long — make sure your storage space can accommodate it.
- Forgetting to account for box weight. A 55L box full of books can weigh 20-25kg, which is heavy for most people to carry up stairs or lift onto a high shelf. If you have back problems or need to move the boxes frequently, use smaller 35L boxes for heavy items and keep the large boxes for lightweight things like bedding.
- Not considering stack height. A stack of four 55L boxes is roughly 1.2-1.4m tall — make sure your storage shelf or loft space has enough vertical clearance. If you're stacking boxes in a garage or shed, remember that the ceiling height might be lower than you think, especially if there are roof trusses or lighting fixtures.
- Choosing cardboard boxes for long-term storage in a damp environment. Cardboard absorbs moisture and can weaken over time, especially in a garage, loft or shed. For long-term storage in a damp environment, use clear plastic boxes with secure lids — they're more expensive but they protect your belongings from damp, pests and crushing.
What to look for when buying storage boxes
Box material matters for durability and protection. Corrugated cardboard is the standard for house moves and short-term storage — it's cheap, recyclable and easy to label. For long-term storage or valuable items, choose rigid plastic boxes with secure, snap-shut lids. Clear plastic lets you see the contents without opening the box, which saves time when you're looking for something specific. Avoid thin, flimsy plastic boxes that crack when stacked.
Lid design affects how easy the boxes are to use. A lid that lifts off completely is easier for packing and unpacking than one that hinges or clips shut. Stackable boxes with interlocking lids (sometimes called 'totes') won't slide off each other when stacked, which is safer and more stable. If you're storing boxes in a loft or garage, look for boxes with a weight rating — some plastic boxes are rated to hold 30-50kg when stacked.
Finally, think about labelling. A box with a blank surface is easier to label than one with a textured or patterned exterior. Use a permanent marker or a label maker to write the room and contents on each box — 'Bedroom 1 - Books and ornaments' is more useful than 'Misc'. If you're using clear plastic boxes, you might not need to label them, but a quick note on the lid still helps when you're searching for something specific.
More questions answered
How do I estimate the volume of what I need to store?
If you're not sure, a good starting point is to count how many standard house-move boxes (around 50-60L each) your belongings would currently fill, then multiply by that figure. Alternatively, measure a rough stack of items directly using length × width × height in litres.
Is it better to use fewer large boxes or more small ones?
Larger boxes hold more but get heavy and awkward quickly, especially with dense items like books. Smaller boxes are easier to carry and stack neatly on shelving, so many people use large boxes for lightweight bulky items (bedding, soft toys) and smaller boxes for anything heavy.
Should I leave extra room in each box?
Yes — this calculator adds a little headroom to the volume estimate since irregularly shaped items rarely pack together as efficiently as a perfect cube. Leaving a bit of slack also makes lids easier to close and boxes easier to stack.
Are clear plastic boxes better than cardboard for long-term storage?
Clear plastic boxes are more resistant to damp, pests and crushing than cardboard, and let you see the contents without opening the lid — worth the extra cost for a loft, garage or shed where conditions vary more than an airing cupboard.
How do I pack fragile items safely?
Use smaller boxes for fragile items (china, glassware, ornaments) so they don't get crushed by heavier boxes stacked on top. Wrap each item individually in bubble wrap or packing paper, and fill the gaps in the box with packing peanuts, scrunched paper or old towels. Label the box 'FRAGILE' on all sides, and stack it on top of heavier, more robust boxes.
Should I vacuum-pack clothes before storing them?
Vacuum packing is great for reducing the volume of clothes, duvets and pillows — it can cut the volume by 50-70%. However, don't vacuum-pack delicate items like wool or silk for long periods, as the compression can damage the fibres. For seasonal storage (3-6 months), vacuum packing is fine. For long-term storage (a year or more), use regular boxes with mothballs or lavender sachets to protect against moths.
How long can I store items in a loft or garage?
Most household items can be stored for 1-2 years in a dry, well-ventilated loft or garage if they're packed properly in sealed boxes. In a damp environment, or if the boxes are in direct contact with the floor or walls, items can start to suffer from damp, mould or pests within 6-12 months. Use plastic boxes with tight-fitting lids for long-term storage, and avoid storing anything sensitive to temperature or humidity (electronics, photographs, musical instruments) in a loft or garage.
What's the best way to label storage boxes?
Use a permanent marker or a label maker to write the room and a brief list of contents on each box — 'Bedroom 1 - Books and ornaments' is more useful than 'Misc'. If you're using clear plastic boxes, you might not need to label them, but a quick note on the lid still helps. Number the boxes and keep a simple inventory list on your phone or a piece of paper — it makes unpacking much faster and helps you find specific items without opening every box.