Down-jacket labels: fill power, fill weight and total weight

A down jacket can carry an 800 fill-power label and still weigh much less than 800 grams. The number describes a property of the down, not the mass of the jacket. A second figure may describe the down inside it, while a third covers the complete garment.

Keeping those fields separate makes a product comparison more useful. This guide reads manufacturer specifications and a clearly fictional comparison; it does not report wearing, weighing or laboratory testing of any jacket.

Separate the three questions

Rab’s fill-power explanation describes how higher fill-power down lofts more and traps more air relative to its weight. Fill power is not the amount of down supplied. An 800FP label therefore does not mean 800 grams of filling, and it does not tell you the jacket’s total weight.

Mountain Equipment’s down guide distinguishes that quality measure from fill weight: the quantity of down in the product, expressed in grams. Total garment weight is a separate field covering the jacket rather than just its filling. Shell, lining, zips and other components contribute to what you carry.

Read one complete product example

The European listing for the Rab Men’s Neutrino Pro, product code QDB-85, states 800FP European goose down, an insulation amount of 212 g for UK size M, and a garment weight of 563 g for size M.

Keep the headings and size qualifications with those numbers. The 212 g belongs inside the 563 g total; adding them would count the filling twice. The 800FP figure is neither of those masses. This is an example of interpreting that particular listing, not a promise that every Neutrino model, size or production version has identical specifications.

The page also identifies outer and lining fabrics separately. Those material descriptions help explain why a jacket weighs more than its down. They do not let us assign exact individual weights to the zip, hood or shell.

Compare equivalent fields

Here are two invented size-M specifications. They are not Rab products, tested samples or recommended purchases.

Fictional size-M jackets: identical down figures, different total weights

Field	Jacket A	Jacket B
Fill power	800FP	800FP
Down weight	150 g	150 g
Total weight	450 g	600 g

B weighs 150 g more overall, yet both contain the same stated amount of down with the same fill-power label. The extra garment weight is not extra down. It belongs to the remaining components in this simplified example.

These fields alone cannot establish which finished jacket is warmer. Nor does A’s lower total make it a better choice for every purpose. The table helps compare quantities; it is not a thermal-performance test.

Keep missing details visible

If a listing says only “Weight: 400 g”, first establish whether that means the whole jacket or its insulation. Record the reference size and any included accessories when supplied. Leave an absent fill weight as unknown instead of estimating it from a photograph, the jacket’s puffiness or its fill-power number.

Use the same product reference and selected version when collecting details from different pages. A useful question for the seller is: “For this model and size, what is the down fill weight, and what does the total listed weight include?” Our shell-and-lining composition guide explains another reason to keep component headings attached to their figures.

Check the finished jacket separately

Mountain Equipment discusses stitch-through and box-wall construction as different ways of containing insulation. Its guide also explains why it does not give its jackets universal temperature ratings: people and activities differ. Fill power by itself supplies no safe minimum temperature.

Read the product’s construction, fit and intended-use details alongside the three numbers. Our rain-shell construction guide covers a different label: bonded fabric layers. Neither a layer count nor a down specification replaces information about the finished garment.

Practical takeaway

Write down fill power, down fill weight and total garment weight in separate boxes. Preserve the stated size, mark missing information and avoid adding the filling to a total that already includes it. Use the result to ask better questions about the exact jacket, not to invent a warmth ranking.