Fill Power and Fill Weight: 550, 650 and 800 Explained
Understand the difference between fill power and fill weight, and how to match a warmth level to temperature, activity level and layering.
Written and reviewed by Leo Wong Man Chon · Founder & CEO, iGift Custom Down Jackets · 2026-08-14
What fill power actually measures
Fill power refers to the volume in cubic inches that one ounce of down occupies. A higher number means more air is trapped for the same weight, giving a better warmth-to-weight ratio and easier packing. Common corporate options include 550, 650, 700 and 800 or above.
Fill power is not the only variable. Warmth also depends on fill weight, fit, the layer underneath and the wind resistance of the shell. A higher-fill-weight 550 jacket can be warmer than a low-fill-weight 800 jacket, although it will weigh more.
How fill weight changes overall warmth
Fill weight is the actual number of grams of down used. Roughly speaking, overall warmth scales with fill power multiplied by fill weight, then is influenced by fit and layering. Choose the intended temperature first, then decide the combination of fill power and grams rather than judging a single figure.
For teams that walk, carry or lift regularly, a lower fill weight with a wind-resistant shell and a moisture-wicking base layer is often more comfortable than a heavy fill. Static posts and long outdoor shifts need a higher warmth level.
Matching warmth level to temperature and activity
The ranges below are general guidance only; individual cold tolerance, wind, sunlight and base layers all affect the right choice.
- Hong Kong winter around 10–18°C: light down vest or 60–100g down jacket
- Around 5–10°C: roughly 100–150g fill, or a 550–650 fill power mid-weight style
- 0–5°C or long static duties: 150g+ fill, or 700+ fill power with layering
- Below 0°C or in strong wind: high fill weight plus a wind-resistant shell, hood and accessories
- High activity levels: lower fill weight with better ventilation and a wicking base layer
Corporate down jacket buying checklist
| Use case and temperature | Define the lowest working temperature, daily wear time, activity level and team roles. |
|---|---|
| Fill and warmth level | Confirm down or synthetic fill, fill weight, fill power and care requirements. |
| Branding method | Prepare artwork and confirm embroidery, screen print or heat-transfer placement and size. |
| Sizing and timing | Collect XS–3XL sizing and allow the standard 3–15 working day lead time. |
Frequently asked questions
- What is the minimum order for custom down jackets?
- The minimum order is 10 pieces. Final pricing and production planning depend on the style, fill, logo method and quantity.
- What information helps iGift recommend a suitable down jacket?
- Share the use case, winter temperature, expected quantity, required date, size range and logo artwork so our team can compare down jackets, padded jackets and vests by fill, branding method and timing.
- What is the standard lead time?
- The standard lead time is 3–15 working days, depending on the confirmed style, quantity, fill availability and branding method.