Updated September 2026. Written from the measurements of our own range and 499 Naturyl customer reviews — including the ones from people who trimmed their piece after it arrived, which is the most useful thing on this page.
The short answer
Extension length is measured from where the piece sits on your head, not from your scalp and not from your ends. A 16 inch piece does not give you 16 inches of new hair — it hangs 16 inches down from a wire that sits near your crown, which on most people lands somewhere around the mid-back.
The trade-off nobody mentions: longer pieces are heavier. Ours run 90g at 12 inch up to 120g at 18 inch — about 10g more for every two inches. Fine hair notices that weight faster than it notices the extra length, which is why the shortest length that solves your problem is usually the right one.
The thing almost everyone gets wrong
Extension lengths are quoted as the length of the hair itself, measured from the top of the weft to the tips. They are not a promise about where the hair will finish on you, because that depends entirely on where the piece sits and how tall you are.
A one-piece wire extension sits like a headband, roughly at the crown. Clip-in wefts sit lower, wherever you place them. So the same 14 inch piece finishes in a different place on two different people, and in a different place again depending on whether you wear it high or low.
Before you choose, do this. It takes ten seconds and it is more reliable than any size guide.
- 1Find where the piece will sit. For a wire piece, put a hairband on the way you would wear it — around the crown, above the ears. For clip-ins, decide which section you will clip into.
- 2Measure from there to your own ends. A tape measure down the back, from the band to where your hair actually finishes. That number is the length that matches what you have.
- 3Decide which job you are buying for. To add thickness, pick the length closest to that measurement so the piece finishes where your own hair does. To add length, go above it — and accept that the further you go, the more work the blend needs.
- 4If you are between two, take the longer one. Hair can be cut shorter. It cannot be made longer. Trimming a piece to your exact line is a ten-minute job for a hairdresser and plenty of our customers do exactly that.
What each length actually does
These are the measurements and weights of our one-piece wire extensions. The weight column is the one to read twice.
"Roughly" is doing real work in that third column. A 5'2" frame and a 5'10" frame wear the same piece very differently, which is why the measurement in step two beats any chart, including this one.
Why longer is not simply better
Every extra inch is extra hair, and extra hair is extra weight hanging from the same clips or the same wire. The difference between our shortest and longest standard piece is 30g, which does not sound like much until it is attached to fine hair for a full day.
+10g
Roughly what each extra two inches adds to the weight
45g
The Lightweight 12 inch — half a standard piece, for fine hair
12 in
The easiest length to hide, and where most people should start
There is a second reason to be cautious about going long. The further past your own ends a piece hangs, the more of it has nothing of yours to blend into — and a solid curtain of extension hair below a thinning natural end is exactly the look everyone is trying to avoid. Length is the part of this purchase where restraint reads as expensive.
Four lengths, plus a lightweight
Invisible Wire Extensions
One piece on a clear wire, 12 to 18 inch at 90g to 120g, plus a 45g Lightweight 12 inch for hair that cannot carry a full piece.
100% Remy human hair · from £89 · Rated 4.7 "Excellent" on Trustpilot · Free UK delivery · Free colour exchanges
Shop invisible wire extensions → Free colour match from a photoYou can cut it shorter. You cannot make it longer.
This is the asymmetry that should settle most close calls. Extension hair takes a scissors exactly like your own, so a piece that arrives slightly too long is a small job. A piece that arrives too short is a piece you have to live with or exchange.
"Lovely extensions very soft look very natural when clipped in the colour is perfect just need to get my hairdresser to cut the length to match my hair very happy with the quality and service"Michelle H., verified buyer
Trimming does more than shorten. Cutting a few soft layers into the ends is what stops a piece reading as one blunt curtain, and it is the difference between extensions that look styled and extensions that look bought. If you are having your own hair cut anyway, take the piece with you.
"Got my hairdresser to trim them and get my lowlights to blend in, love how natural & rich they look. I forgot I’m even wearing them, so simple to use 🫶"Michele D., verified buyer
Thickness can be adjusted the same way. One customer found her 14 inch piece too dense for her hair and simply removed a couple of sections from the weft — a reminder that these are not fixed objects.
Lengths in the other formats
Not everything comes in four lengths, and for the smaller pieces that is deliberate — they exist to do one job.
Face-Framing Layers — 14 inch. One length, because they sit at the front and frame the face. Shorter would not reach; longer would stop being face-framing and start being a full piece.
Side fill-ins — one length. These fill sparse sides and temples rather than adding length at all, so the measurement that matters is the width of the base, not the drop.
Clip-in ponytails — 16 or 18 inch. 80g and 90g respectively. A ponytail is worn high, so it hangs from much further up your head than a wire piece does — which is why 16 inch on a ponytail reads considerably longer than 16 inch on a wire.
That last point catches people out more than any other. The same number means a different finished length in a different format, because the starting height is different. Always ask where the piece sits before comparing two numbers.
If length is not the problem
Face-Framing Layers
Two small 14 inch pieces on inch-wide clips, in 29 shades. For hair that is thin at the front rather than short — the least you can spend to see how a piece sits against your own hair.
Front clip-in extensions · 100% Remy · £36 · Free UK delivery · Free colour exchanges
Shop Face-Framing Layers →Common questions
How long is a 12 inch hair extension?
The hair itself measures 12 inches from the top of the weft to the tips. Worn on a wire that sits near the crown, that usually finishes somewhere around the shoulder, though your height and where you position the piece both change it. Measure from where the piece will sit down to your own ends before you choose.
What is the most popular hair extension length in the UK?
12 and 14 inch cover most people, because most people are adding thickness to hair that already reaches the shoulder rather than adding dramatic length. Shorter lengths are also lighter and easier to hide, which matters more than it sounds if your hair is fine.
How do I know what length hair extensions to buy?
Put a hairband where the piece will sit, measure from there to your own ends, and compare. Match that number to add thickness; go longer to add length. If you fall between two sizes, buy the longer one — you can always trim it, and you cannot add hair back on.
Can you cut hair extensions shorter?
Yes. It is real Remy human hair, so it cuts exactly like your own, and plenty of customers have a hairdresser trim theirs to match. Cutting a few soft layers into the ends also helps the piece blend rather than hanging as one blunt curtain.
Are longer hair extensions heavier?
Yes, and it is worth taking seriously on fine hair. Our wire pieces run 90g at 12 inch to 120g at 18 inch — roughly 10g for every two inches. There is also a 45g Lightweight 12 inch, which is about half the weight of a standard piece.
Is 16 inch too long for shoulder-length hair?
It will add real length rather than thickness, so it depends which you want. The catch is that everything hanging below your own ends has nothing of yours to blend into, so the join shows more the further you go. If you mainly want fullness, 12 or 14 inch will look more natural.
