Short answer: there is no single correct weight for everyone. Many full applications often fall somewhere around 100–200 g, but the right quantity can be lower or higher depending on the density of the natural hair, starting length, desired final length and, above all, the extension system being used.
The important point is this: more grams do not automatically mean a better result. Too little hair can leave an empty blend or thin-looking ends; too much can be unnecessary, unnatural and unsuitable for the natural base.
What really determines the amount you need?
The quantity should be assessed alongside four elements: natural hair density, the difference between starting and desired length, the perimeter of the haircut and the construction of the chosen method. A full bob that needs to become very long will normally require more material than already-long hair that only needs extra density.
Texture also changes how volume is perceived: 100 g of straight, wavy and curly hair will not necessarily create the same visual effect.
Why can’t you compare grams without considering the method?
A micro-ring weft, strand-by-strand keratin bonds, a tape system and a clip-in set all have different constructions. Two products with the same weight therefore do not necessarily cover the same area of the head or behave in the same way.
In the VELVET catalogue, for example, VELVET Bridge XL is available in 50, 100, 150 and 200 g, while VELVET Tape XL is configured in 60, 120, 180 and 240 g. VELVET Fusion, meanwhile, distributes the weight through small strands, with quantities from 25 to 200 g. These figures describe different product configurations, not a universal ranking.
A practical rule that is more useful than fixed numbers
The right question is not “how many grams are normally used?”, but how many grams are needed to blend this natural base without overloading it? If the aim is only to add density to one area, a relatively small amount may be enough. If a short, full haircut needs to become significantly longer, more material is required because the natural perimeter has to disappear into the new volume.
For fine hair, the limit is not purely aesthetic: the quantity must be compatible with what the natural hair can support and conceal. We explore this in Which Hair Extensions Are Best for Fine Hair?.
If the starting point is very short, blending becomes the main issue. See also Can You Wear Extensions on Short Hair?.
In summary
The number of grams is a consequence of the project, not the project itself. Density, length, haircut, texture and method come before the number on the packaging. A credible choice therefore avoids automatic formulas and considers weight within the context of the entire application.