Guide · Fabric Weights
Ask three fleece suppliers for "a fleece jacket" and you can receive three garments that share nothing but a zipper. The variable that explains most of the difference — in warmth, in hand feel, in price — is fabric weight, expressed in GSM: grams per square metre of fabric. This guide explains how the GSM ladder works in our fleece program, what each step is actually for, and how to specify weight so the bulk matches the sample.
What GSM measures — and what it does not
GSM is the mass of one square metre of the finished fabric. In micro fleece, that mass is almost entirely polyester fibre raised into a brushed pile on one or both sides. More fibre per square metre can support a denser pile and more trapped air, but warmth also depends on pile structure, fabric construction, garment fit, layering and wind exposure. GSM does not measure quality by itself: a well-made 280 GSM micro fleece with a tight, even pile may perform differently from a poorly made 320 GSM fabric with thin patches. GSM remains useful because it is a measurable specification that can be written into a purchase order and checked on delivery with a scale and a cutting die, rather than relying on descriptions such as "thick" or "thin".
One caution on comparisons: weights are only comparable within the same fabric construction. A 300 GSM softshell (woven shell plus fleece lining plus bonding) is not "warmer" than a 280 GSM pure fleece in any simple sense — the numbers describe different stacks. This guide deals with fleece-to-fleece comparisons; softshell builds are covered in our 2-layer vs 3-layer softshell guide.
The ladder, step by step
| Weight | Program role | Where it is specified |
|---|---|---|
| 160 GSM | Light fleece tops | Layering pieces, mild seasons, indoor teams, under-shell warmth |
| 280 GSM | Core jacket & vest weight | The default for staff jackets and vests — our Basic Jacket and Basic Vest |
| 320–330 GSM | Finished jacket/vest quality | Heavier programs, cold-climate issue, premium resale ranges |
| 350 GSM | Patchwork styles | Two-tone constructed jackets where panels carry extra body |
160 GSM — the layering weight
At 160 GSM micro fleece is a top, not a jacket: soft, light, and designed to disappear under a shell or over a base layer. It suits fleets whose staff move between heated vehicles and short outdoor tasks, healthcare teams in climate-controlled buildings, and any program where the fleece is one layer in a system rather than the outer garment. Specifying 160 GSM for an outdoor crew is the most common under-specification error we see; the garment will be well made and the complaints will still arrive in January.
280 GSM — the core weight
Most wholesale fleece programs sit here, for good reason. A 280 GSM jacket carries enough pile to work as a standalone outer layer in cool conditions, still layers under a softshell or padded jacket without binding, and hits the price point where distributors can hold margin and employers can issue without a budget fight. Our basic jacket and basic vest are both blocked at 280 GSM. If you are speccing one weight for a mixed team and mixed duties, this is the step to start sampling from.
320–330 GSM — the heavy finished quality
Our finished fleece jacket and vest qualities run at 320–330 GSM, and the difference from 280 is immediately obvious in the hand: denser pile, more structure, a garment that reads as outerwear rather than mid-layer. Cold-region programs, outdoor resale ranges and buyers replacing a heavier incumbent product specify this band. The trade-offs are unit cost (more fibre, more freight weight) and drying time after washing.
350 GSM — patchwork and maximum fleece builds
At 350 GSM we build patchwork jackets — two-tone panel constructions where the heavier fabric gives panels the body to hold the design. This is the top of the pure-fleece ladder in our program. If a program needs a different balance of warmth, weather exposure, bulk or cost, a three-layer softshell or a padded jacket can be compared as an alternative construction; which one is better value depends on the job conditions and the quotation, not on GSM alone.
How weight drives cost
Fibre mass rises with GSM — a nominal 320 GSM fabric has about 14% more mass per square metre than a 280 GSM fabric — but total garment cost does not have to move in the same proportion. Construction, pattern yield, trims, workmanship, order terms and freight also matter. If a quotation looks unusually low for a heavy specification, check the fabric weight as part of the review: write the GSM into the PO, weigh the pre-production sample's fabric, and re-weigh a square cut from a bulk carton on arrival.
Matching weight to program: a quick decision path
- Indoor or vehicle-based team, heated environment: 160 GSM top, or 280 GSM vest over work shirts.
- Mixed indoor/outdoor staff, one garment to issue: 280 GSM jacket — the default answer.
- Outdoor crews, cold region, or premium resale: 320–330 GSM jacket, or step sideways to a softshell build if wind and drizzle are part of the job.
- Brand-led range that must look distinctive: 350 GSM patchwork construction.
- Layering system (fleece under padded outer): drop the fleece one step — 160 or 280 — and let the padded layer carry the deep-winter warmth.
Weight tolerance: the number behind the number
No knitted fabric leaves the mill at exactly its nominal weight across every roll, and honest programs talk about tolerance rather than pretending otherwise. What matters commercially is threefold: that the fabric is knitted to the specified step (a 280 GSM program must not quietly be a 250 GSM fabric with optimistic paperwork), that weight is consistent within a production lot so every wearer gets the same garment, and that your sample and your bulk come from the same specification. When you evaluate suppliers, ask how weight is controlled and checked — a manufacturer who publishes the ladder, as we do, is telling you the number is a production parameter with a QC step behind it, not a marketing adjective. If a supplier will not put a GSM figure in writing at all, the weight conversation is already over.
Washing is the other place weight tells the truth over time. A properly finished micro fleece holds its pile and loft through repeated laundering; an under-finished fabric sheds fibre, thins at rub points and measures lighter after a season of washes than it did at delivery. That is why GSM belongs in the re-order conversation too: when a replacement quote comes back cheaper on "the same jacket", weigh the fabric of the new sample against a square cut from your original bulk garment. Two minutes with a scale protects the whole program.
Writing the spec
A fleece jacket spec that survives production has five elements: fabric (100% micro fleece), weight in GSM with the step named, style block (jacket, vest or top; men, women or unisex), color set, and branding method. Send those five with your quantity and we can quote without a clarification round. The wholesale fleece jacket page shows the reference styles and program terms, and if weight is only one of several open decisions, work through the winter staff jacket procurement checklist in order — it is sequenced in the order the decisions come up.