3 min read
The bin liner size finder starts from a bin. This starts from a job: this sack has to carry fifteen kilos of wet kitchen waste and be carried across a yard.
Two things decide the answer, and they fight each other. The weight sets how much film the sack needs to hold together. The waste sets a floor below which nothing holds together at all.
The job
The sack
The P figure. Use the bin liner size finder if you do not have one yet.
This calculator works out the answer in your browser, so it needs JavaScript switched on. If you would rather not, send us the figures and we will run it for you — the answer comes back the same day.
The load figures are a working rule calibrated against the specifications we ship, not a test standard. EN 13592 classifies sacks by drop test, and on a marginal call a sample tested with your own waste is the only thing that settles it. We send samples free.
Want this as a PDF? The answer above is yours either way. The PDF is the working written out — the figures you entered, the result, and the assumptions behind it — for a colleague or a purchase requisition.
What a sack carries
Capacity rises with thickness and with width — a wider sack spreads the same load over more material. The working relation is
capacity (kg) ≈ 0.25 × thickness (µm) × width (mm) ÷ 500 × polymer factor
which puts a 500 mm LDPE sack at 30 µm on about 7.5 kg, and a 450 mm HDPE sack at 12 µm on about 5.7 kg — the figure the trade quotes for light office waste.
This is a working rule calibrated against the specifications we ship, not a test standard. EN 13592 classifies sacks by drop test, and on a marginal call a sample filled with your own waste is the only thing that settles it. We send samples free, and the reason is entirely self-interested: a sack that fails in week three is a customer lost and a collection to re-run.
What the waste demands regardless
Fifteen kilograms of paper and fifteen kilograms of broken tile are the same load and not remotely the same sack. One fails in tension, the other by puncture, and no amount of tensile capacity fixes a corner going through the wall.
| What goes in | Floor | Polymer |
|---|---|---|
| Office — paper, dry packaging | 12 µm | HDPE |
| Retail and general commercial | 25 µm | LDPE |
| Hotels, restaurants, catering | 35 µm | LDPE |
| Industrial — offcuts, sharp edges | 50 µm | LDPE |
| Healthcare — clinical or offensive | 50 µm | LDPE |
| Construction and demolition | 75 µm | LDPE |
When the floor is what decided the answer rather than the weight, the calculator says so — because it changes what you do about it. If the load is what binds, a wider sack or a lighter fill helps. If the waste is what binds, neither does.
How it is handled changes the specification
A sack that is tipped from a bin never carries its own contents; the bin does. A sack that is gathered, lifted and carried takes the whole load on its own film and its base seam. A sack that is dragged across a yard or thrown into a skip takes that and abrasion as well.
The calculator applies half the load for tipping, the full load for carrying and a 60% surcharge for dragging. That surcharge is usually worth more than any specification change: if the sacks can be lifted instead of dragged, two duty classes come off the order.
HDPE only earns its place in one row
HDPE carries roughly twice the tensile load of LDPE per micron and much less against a corner. That makes it genuinely right for paper and dry packaging — half the polyethylene for the same job — and wrong for everything else on that table, regardless of what it costs.
If a quotation offers HDPE for food waste, it is not a like-for-like alternative. See the micron and gauge converter for the equivalence in both directions.
Sacks per tonne
Sacks are priced per tonne and bought per case, and the bridge between the two is the weight of one empty sack — two walls of film, which is the number people forget:
grams = 2 × width (cm) × thickness (cm) × length (cm) × density
A 600 × 900 sack at 40 µm weighs 39.7 g, so a tonne is about 25,000 sacks. When a competitor quotes per thousand and we quote per tonne, that is the figure that makes them comparable — and the roll yield calculator does it in both directions.
What we quote
Sack quotations from us state the EN 13592 size, the thickness in microns, the polymer and its recycled content, the colour, the number per roll or case, and the cases per pallet.
Send us what you buy today and what it has to carry. If the specification is heavier than the job needs — which is the common finding — we will say so and quote the lighter one alongside it.