Outdoor Storage Box Calculator
An undersized outdoor storage box leaves cushions, tools or toys spilling out into the weather, while an oversized one wastes valuable patio or garden space. Enter the total volume of what you need to store below to get a recommended box size.
Work out what size outdoor storage box you need
Estimate the total volume of what you want to store outdoors, such as cushions, tools or toys.
Allowing 15% extra headroom for awkward shapes, the smallest standard size that fits is:
270L outdoor storage box
That gives you room for around 230L of items with a little spare capacity.
Recommended products
A few well-reviewed outdoor storage boxes to consider.
- Resin
- Cushion Storage
£145.00
Pros
- Compact footprint suits small patios and balconies
- Weatherproof resin needs no annual treatment
- Generous 880L capacity for the footprint
Cons
- Larger than the old Lite model, so measure your space first
- Resin
- Garden Furniture Cushions
£53.90
Pros
- Textured resin wicker finish for a smarter look on decking
- Hinged lid stays open while loading and unloading
- 375L capacity for cushions and garden accessories
Cons
- Base can flex slightly on uneven paving
- Resin
- Bike Storage
£384.98
Pros
- 2000L capacity fits two adult bikes with room to spare
- Piston-assisted lid opens from top or front with sloped threshold for wheeled items
- Fully lockable for secure outdoor bike storage
Cons
- Large footprint needs a level, dedicated spot
- Requires two people for assembly and positioning
Frequently asked questions
How do I estimate the volume of items I want to store outdoors?
A rough way is to measure the length, width and height of your items (or the pile of cushions, toys or tools) in centimetres, multiply them together, then divide by 1,000 to convert to litres.
Why does the calculator add extra headroom to my volume estimate?
Items rarely pack together perfectly, especially bulky or irregularly shaped things like cushions or garden toys, so adding around 15% extra headroom helps avoid buying a box that turns out to be just too small.
Should I choose a bigger box than I need right now?
It is often worth sizing up slightly if you expect to add more items over time, such as extra garden furniture cushions or toys, since it is more convenient than replacing the box later.
Are outdoor storage boxes weatherproof?
Most dedicated outdoor storage boxes are designed to be weather-resistant, but it is still worth checking the product details for features like a rain-shedding lid and drainage to keep the contents dry.
How this calculator works
The Outdoor Storage Box Calculator uses a straightforward volume calculation to determine the required storage capacity. You’ll input the approximate dimensions – length, width, and height – of your items in centimetres. The calculator then multiplies these values together (Length x Width x Height) to give you the internal volume in cubic metres (m³). This represents the amount of space needed to comfortably store your belongings.
We assume a standard fill ratio of 65%. This accounts for gaps between items and allows for some wiggle room. A storage box that’s too full will be uncomfortable to access, while one that's significantly underfilled might not offer sufficient protection from the elements. The result is displayed in cubic metres (m³) which represents the volume of space your chosen storage box needs to accommodate.
Cushion & Tool Storage - UK Size Guide
- **Average Cushion Dimensions:** Most outdoor cushions measure approximately 180cm x 90cm x 25cm – this will require around 4.06 m³ of storage space.
- **Typical Garden Tool Set:** A standard set of garden tools (shovels, rakes, spades) usually occupies a volume of around 0.75 m³, assuming a reasonable amount of padding and protection.
- **Children’s Toys:** A collection of outdoor toys for children might need roughly 1.2 m³ of storage space depending on the size and quantity of items.
- **Larger Items – Patio Furniture:** Larger patio chairs or small tables can require up to 3.5 m³ or more, particularly if you have multiple pieces.
- **Consider Protection:** Always factor in extra space (around 20%) for protective layers like bubble wrap or blankets, especially during harsh winter months.
Worked example: Calculating Storage Needs
Let’s say you're planning to store a set of six outdoor cushions (180cm x 90cm x 25cm) and a collection of gardening tools in a new weatherproof storage box. Using the calculator, we input these dimensions and get a total volume requirement of approximately 4.06 m³.
Considering the 65% fill ratio, you'd ideally want a storage box with an internal capacity of around 2.64m³. Looking at Amazon UK, you might consider purchasing a plastic outdoor storage box measuring 130cm x 70cm x 40cm which has an internal volume of approximately 3.64 m³ – offering sufficient space and some extra room for padding.
More questions answered
What does the result in cubic metres actually mean?
The result is a measure of volume, representing the amount of space your storage box needs to comfortably hold your items. It's important to remember that we’ve factored in a 65% fill ratio – this means you won’t need to completely pack the box full.
Can I use this calculator for larger furniture?
Yes, but you’ll likely need significantly larger storage boxes. Items like small patio sets or even garden sheds require careful calculation. Consider using a larger unit of measurement – perhaps litres – when estimating volume if your items are irregular shapes.
What if my cushions aren't all the same size?
The calculator provides an average based on typical cushion sizes. To get a more accurate result, try to measure the dimensions of each individual cushion and calculate the total volume accordingly. Adding these volumes together will give you a better estimate.
Does the fill ratio always stay at 65%?
The 65% fill ratio is an approximation. If you’re storing items with very little space between them (e.g., tightly packed tools), you might need to adjust this figure slightly. Err on the side of caution and opt for a larger storage box.
How does weatherproofing affect my storage needs?
Weatherproof storage boxes are designed to protect your items from rain, snow, and sun damage. This means they’re more durable and less prone to absorbing moisture, so you might be able to pack them slightly tighter without compromising protection.
What if I want to store things that aren't neatly packed?
This calculator assumes a reasonably organised storage layout. If you plan on storing items haphazardly, it’s best to overestimate the volume required by adding an extra 20-30% buffer to your calculations.
Can I use this calculator for tools that are oddly shaped?
It's more difficult to get an accurate measurement with irregular shapes. Try to approximate their dimensions using multiple measurements and add a substantial safety margin (around 30%) to account for the space they occupy.
What if I’m only storing cushions in winter?
Even when not in use, cushions can still benefit from protection against dust and UV rays. The calculation is still valid; simply adjust your cushion dimensions to reflect their current state – perhaps slightly compressed.
Are there any alternatives to cubic metres for measuring storage space?
While cubic metres are most accurate, you could also use litres or gallons as a guide. However, remember that these units don’t account for shape and will likely overestimate the required volume.
Where can I buy the storage boxes suggested by this calculator?
You can find a wide range of weatherproof outdoor storage boxes on Amazon UK in various sizes and materials to suit your needs. We've linked directly to product listings for convenience – explore our selection today!