What Size Bin Liner Do I Need?
If you've ever bought a bag of bin liners only to find them either swimming in the bin or too small to tie properly, you already know why size matters more than it seems like it should. The good news is that once you know a few real measurements, rather than just a litre number, choosing the right liner is genuinely simple.
This guide covers the most common UK bin sizes, from small kitchen caddies through to larger household bins, so you can match a liner to your bin in a couple of minutes. If you're looking specifically at compostable liners, we've also included the material detail that doesn't usually get covered elsewhere.
Quick-start: match your bin to a size
Liner size | Suitable for | Bin height (max) | Rectangular opening, L+W (max) | Circular opening (max) |
3 to 6L bins | 30cm | 40cm | 25cm | |
6 to 10L bins | 40cm | 40cm | 25cm | |
13 to 20L bins | 45cm | 55cm | 35cm | |
23 to 30L bins | 55cm | 60cm | 38cm | |
35 to 50L bins | 70cm | 64cm | 41cm |
These litre ranges are rough bands rather than a precise scale, they're built around each liner's real height and opening limits, not evenly spaced litre markers, so a bin that doesn't land neatly inside one of the ranges above isn't a sign that nothing in the range fits.
For the best fit, measure your bin's height and opening and check them against the table rather than relying on the litre number alone, and if you're ever between two sizes, pick the one up rather than down. A liner with a little extra room folds over the rim neatly and gives you more to work with when tying it off; one that's slightly too small is more likely to slip or tear at the seams.
A note on kerbside caddies: most UK councils issue a 23 litre food waste caddy for kerbside collection. Based on our size ranges, we've found a 30L liner fits best, leaving some additional room to tie with ease. It's worth checking your own caddy's capacity and opening size, since council caddies can vary from area to area.
Why litre capacity only gets you part of the way there
Litre capacity is a useful starting point, but it doesn't tell the whole story. Two bins can both be rated at, say, 20 litres while being quite different shapes, one tall and narrow, another short and wide, and a liner sized for one won't necessarily suit the other properly.
What actually determines fit is the bin's opening, either the width of a rectangular opening or the diameter of a circular one, and its height. That's why each of our liners is specified against those exact figures, alongside the suitable bin size range, in the size guide shown on its product page.
If you're working from a bin's external measurements rather than a stated litre capacity, bear in mind that the external size, especially where there's a lid, a pedal mechanism, or a tapered base, doesn't always match the internal opening you're actually fitting a liner around. Measuring the opening itself, as below, is more reliable than judging it by eye.
How to measure your bin if you don't know its size
If you don't have a capacity rating to go on, you can work out the two figures that actually matter, the opening and the height, directly from the bin.
For a rectangular or square opening:
Measure side A and side B of the opening.
Add them together and check this figure against the "rectangular opening" maximum in the table above.
For a circular opening:
Measure the diameter straight across the middle of the opening.
Check this against the "circular opening" maximum in the table above.
Bin height:
Measure from the base to the rim.
Check this against the "bin height" figure in the table above.
Once you have all three, choose the smallest liner size that covers your bin on every measurement, not capacity alone. If your bin sits right on the boundary between two sizes, size up rather than down for a more secure fit.
Does a thinner liner mean a weaker one?
Not necessarily, and this is one area where compostable liners work a little differently to conventional plastic ones.
Across our range, the 6L and 10L caddy liners are made from a 15 micron PLA and PBAT blend, while the 20L, 30L and 50L liners step up to 18 micron. The thicker material on the larger sizes isn't about compensating for weaker material, it's simply that a bigger bag holding a larger volume of food waste needs a bit more body to stay secure when it's lifted out and tied. Smaller caddy liners, holding a lighter and more contained amount of waste, don't need the same thickness to perform properly.
Either way, all our liners are certified to EN13432 and carry TÜV Austria's home compost certification, so the compostability itself doesn't change with size, only the thickness suited to the job.
For businesses managing food waste
If you're setting up food waste separation in an office, café or small business, rather than at home, bin liner sizing works the same way, but there's an added layer to be aware of: Simpler Recycling requirements for separating food waste from other streams. Compostable caddy liners can be collected with food waste under this guidance, though compostable packaging such as takeaway boxes cannot automatically go in the same stream.
Frequently asked questions
What size is a standard UK kitchen caddy?
Most countertop kitchen caddies used for food waste are 7 litres, which our 10L liner is sized for.
What size is my council's kerbside food waste caddy?
This varies by area, but most councils issue 23 litre caddies, so our 30L liners are the right fit. Check the caddy's height and opening against the table above, or its printed capacity if you're not sure.
Can I use a bigger bag than I need?
Yes. A liner that's slightly larger than your bin will simply fold over the rim with a bit more overhang. This is a better outcome than a liner that's too small to seat properly.
Do compostable liners fit the same way as plastic ones?
Yes, capacity and fit work exactly the same way. The only difference is the material itself, not how you size it.
Getting the right fit
Once you know your bin's height and opening size, rather than just its litre rating, choosing a liner is straightforward. Check those figures against the table above, size up if you're between two options, and for food waste specifically, our range runs from a 6L caddy liner up to a 50L liner for commercial bins or larger household bins. Each product page also has its own size guide image if you want to check your bin against that specific liner directly. You can browse the full range here.
