How much hair weave you need?

Hair Extensions

Weave are attached to your head by sewing them to a tiny braid made out of your own hair. The track (known to hairdressers as a corn-row) runs horizontally around the back of your head. The tracks are done in the middle of your scalp underneath your hairline so you can’t see them.
The crown area of your own hair covers the top track making the hair extensions seem invisible. The number and size of tracks matches the number and size of wefts. The wefts and tracks ideally should be made in different sizes in order to match exactly the way your hair would look if you had grown it that way yourself.

Body Wave Clip In Human Hair Extension
Body Wave Clip In Human Hair Extension

Normally, Weft hair are applied in rows across your head with adhesive or sewed to braids. Some hairdressers prefer shrinkies/shrink-links and micro ring or fusion for pre bonded hair, the hair comes already separated into individual strands ready for application with glue on the tips.
How much hair you need depends on how many tracks you have. For example: If I had hair to my chin and I wanted hair to my bra line (about 18″ long) I might need 5 or 6 tracks/wefts depending upon my current haircut. If I had hair to my shoulders that was thin and stringy and I wanted it thicker and more luscious but the same length I might need 2 or 3 (or more) tracks/wefts. For hair weft under 18 inches, one packet is enough for full head. Over 18 inches, you should need more the one. If a hairdresser is doing your hair it is advisable to check with them as to how much you require for the hairstyle.
For the pre blonded hair, you should need 150-200 strands.Once again this depends on the style. For other methods eg strand by strand you will need to consult with your hair dresser. Once the tracks are done, the wefts are sewn to them and then your own crown area hair is blended with and combed over the extensions.

Sure, the Extensions should not be applied any lower than the base of your scalp (about even with the middle of your ears) and so your hair under this point covers the extensions while you wear it in pigtails, ponytails, french twists, french braids etc。 With proper care, Hair Extensions should last four months.

Hope it helps. Further Reading: Weft Hair Extensions