If you have narrowed your choice down to a #5 or a #8 zipper (or “zip”, as it is called in the UK and Australia), you are deciding between the two most common mid-to-heavy gauges in production. They overlap in some products but behave very differently under load. This guide gives you the quick answer first, then the detail to spec with confidence.
Quick answer
Choose #5 for most jackets, hoodies, mid-weight bags and cushions — it is the everyday default: strong enough for daily use, slim enough to look refined.
Choose #8 for heavy outerwear, parkas, luggage and bags that carry real weight, or when you want a bold, substantial closure as a design feature.
If in doubt and the load is moderate, #5 is the safer, lighter, cheaper choice.
What the numbers mean
A zipper’s size is the approximate width of the closed chain in millimetres: a #5 is about 5 mm wide, a #8 about 8 mm. Bigger number = wider teeth, larger slider, more strength and more visual weight. (For the full system across #3 to #10, see our complete guide to zipper sizes.)
#5 vs #8 side by side
| #5 | #8 | |
|---|---|---|
| Closed width | ~5 mm | ~8 mm |
| Strength | Medium | Heavy |
| Weight & bulk | Lighter, slimmer | Heavier, chunkier |
| Feel | Refined | Substantial, rugged |
| Typical use | Jackets, hoodies, mid bags | Parkas, luggage, heavy bags |
| Relative cost | Lower | Higher |
When to choose #5
The #5 is the workhorse gauge. Pick it when:
- The garment or bag carries moderate, everyday load — jackets, hoodies, mid-weight totes.
- You want the closure to look clean and proportional rather than bold.
- Weight and cost matter (lighter chain, lower price per metre).
- You need versatility — #5 is available across nylon coil, metal and resin.
When to choose #8
Step up to #8 when:
- The product carries real, repeated load — parkas, technical shells, luggage, heavy-duty bags.
- You want a substantial, premium feel in the hand, or an oversized closure as a deliberate design statement.
- The closure is under tension and must resist separation — wider teeth and a larger slider hold better.
- You are using metal on denim or premium bags, where #8 reads as rugged and high-end.
Type matters as much as size
A #5 and a #8 of the same type differ in strength — but so do two zippers of the same size in different types. A #8 nylon coil is lighter and more flexible than a #8 metal, which feels rugged and premium. Always specify both size and type:
- Metal: strongest feel; common in #5–#8 for denim, leather and bags.
- Resin: light but tough, cold-flexible; strong in #5–#8 for outdoor.
- Nylon coil: lightest and most flexible; great in #5.
Not sure which combination fits your product? See how to measure a zipper to capture the exact spec, then send it to us for a recommendation and sample.
The bottom line
#5 is the everyday default — lighter, slimmer, cheaper, and strong enough for most jackets and bags. #8 is the heavy-duty step up for parkas, luggage and loaded bags, with a bolder, more premium feel. Match the gauge to the load, then pair it with the right type, and the closure becomes a feature rather than a weak point.
Building a product and weighing #5 against #8? Request a quote and samples and we will help you confirm the right size, type and slider.
Frequently asked questions
Is a #8 zip stronger than a #5? Yes. A #8 has wider teeth and a larger slider, so it resists lateral pull and separation better than a #5 — at the cost of more weight, bulk and price.
Can I use a #5 zip on a backpack? For light daypacks, yes. For backpacks that carry real weight or take daily abuse, #8 is the safer choice. See our guide on zipper sizes for bags and backpacks.
Is #5 or #8 better for a jacket? #5 suits most jackets and hoodies. Choose #8 only for heavy parkas and technical outerwear where the closure carries load.
Do #5 and #8 come in waterproof? Yes. Our waterproof zippers are available across #3–#8 with TPU-laminated tape for IPX5 sealing.
