The Fill Power Calculator helps textile manufacturers, bedding designers, outdoor gear brands, and consumers check the loft quality of down insulation used in jackets, sleeping bags, and comforters. Fill power shows how much space one ounce of down can fill when fully expanded. Higher fill power means better insulation and fluffiness with less weight. This tool removes confusion by giving an accurate number based on real measurements. It belongs to the Textile Quality and Insulation Performance Calculator category and supports quality checks and product comparisons.
formula of Fill Power Calculator
Fill Power = Volume Filled by 1 Ounce of Down
Expressed as:
Fill Power (in³/oz) = Volume (in³) / Weight (oz)
Where:
Volume is the measured expand volume the down occupies under standard lab conditions, in cubic inches
Weight is the weight of the down sample in ounces
For standard tests, the down is place in a cylinder and lightly compressed with a weight to check how much air it traps and how high it lofts.
Common Fill Power Ratings Reference Table
This table shows typical fill power ratings for down products so you can compare your calculated results and choose the right insulation.
| Fill Power (in³/oz) | Down Quality Level | Typical Use Case |
|---|---|---|
| 400–450 | Entry Level | General bedding, budget jackets |
| 500–550 | Mid Range | Everyday outdoor gear |
| 600–700 | High Quality | Lightweight jackets, sleeping bags |
| 700–800 | Premium | High-end sleeping bags, ultralight jackets |
| 800+ | Ultra Premium | Expedition-grade gear, luxury bedding |
Higher fill power means less down is needed for the same warmth, which reduces weight and bulk.
Example of Fill Power Calculator
Let’s see a simple example step by step.
You test a down sample that weighs 1 ounce and expands to fill 650 cubic inches.
- Use the formula:
Fill Power = Volume / Weight
Fill Power = 650 / 1 = 650 in³/oz
So, the fill power of this down sample is 650, which is high quality and good for warm but lightweight jackets or sleeping bags.
Most Common FAQs
Fill power shows how fluffy and insulating the down is. Higher fill power traps more air, providing better warmth with less weight, which is ideal for outdoor gear and premium bedding.
Generally yes, but it depends on the use. Higher fill power is lighter and more packable but often costs more. For heavy-duty bedding or casual wear, mid-range fill power might be enough and more affordable.
Fill power is measured in labs using a standardized cylinder and a small weight that compresses the down. This shows how much space the down fills at a set pressure, giving a consistent value for comparison.