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What's This About
An undercut is a haircut with the sides and back clipped to one short length, a number 1 or 2 in the Book of Barbering’s standard order, and the top left long, with a visible line where the two meet instead of a blend; that line is what separates it from a fade, which grades the sides into the top with no edge, and the top can be anything from under two inches to shoulder length, which is why the same word covers so many photographs.
This guide answers the questions men ask before they ask for one, such as
• What is an undercut, and how is it different from a fade?
• Disconnected or blended, and how far up should it go?
• Which versions exist, by the length on top?
• What do I tell the barber, in guards and inches?
• How do I style it, and how often does it need cutting?
and many more!
Each version has its own card with the order, and the line’s height is treated as the decision it is.
Key Points
01The line is the definition. An undercut has a visible edge between short sides and long top; a fade has no edge; a faded undercut keeps the long top and the contrast but blends the sides up into it.
02The height of the line sets the look, so it sits at the parietal ridge (the widest point of the head, above the temples) for the classic cut, lower for a softer one; above the ridge, the long section narrows towards a strip along the top.
03The top decides the version, whether short and textured, medium and swept, long and slicked back, or long enough to tie.
04The order is three parts, the guard on the sides (a 1 or 2), the length on top in inches, and “disconnected” or “blended”.
The short answer
An undercut is short sides, a long top and a line between them.
Wikipedia describes the top as “long”, “often parted on either the side or center, while the back and sides are buzzed very short or shaved”, and the Book of Barbering gives the defining feature as “a sharp, visible line where the short sides meet the longer top”, with no gradual blending.
The cut has a working-class history. From the turn of the twentieth century to the 1920s it was, in Wikipedia’s account, “popular among young working-class men, especially members of street gangs”, including the Peaky Blinders, because longer hair put the wearer “at a disadvantage in a street fight”; styles of this type were mainstream in the Jazz Age, and the cut came back in the early 2010s in an imitation of the 1930s and 1940s version, “longer with pomade in or swept to one side on top and shaved or clipped at the sides”.
The reason it is confusing now is that barbers fade it; the Book of Barbering’s explanation is that “most modern undercuts actually incorporate a fade on the sides”, which is why the two names get mixed up.
The key rule is a number 1 or 2 on the sides, a line at or below the parietal ridge, and a top long enough to do something with; say “disconnected” if you want the line and “blended” if you do not.
Undercut versus fade, and disconnected versus blended
Scroll horizontally to see all columns →
| Term | The sides | The transition | The top | Grows out |
|---|---|---|---|---|
| Disconnected undercut | One guard, a number 1 or 2, up to the line | None, a visible edge | Long | Sharply; it needs a trim every two to three weeks |
| Blended (faded) undercut | A number 1 or 2 at the bottom, blended up to the line | Short blend, no hard edge | Long | More gently |
| Fade | Skin or a number 1 at the bottom, graded up the head | Seamless | Any length | Fastest to blur at the skin |
| Taper | A number 1 or 2 at the neck and ears only | Gradual, low | Any length | Slowest |
The Book of Barbering’s distinction is that a fade “gradually transitions from shorter to longer hair with smooth, seamless blending and no hard line of demarcation”, while the disconnected undercut has “an abrupt transition between the short sides and longer top, with no blending or fading between lengths”; its faded version allows “smoother grow-out periods between cuts”.
Wahl’s guide gives the two options in guard numbers. For a connected undercut, the clipped back and sides are blended into the rim of the head with “a guide comb that is two numbers higher” (a number 3 after a number 1); for a disconnected one, the instruction is “Leave the hair as is without blending”.
The height of the line is the other decision, and the reference is the parietal ridge, the widest point of the head (barbers also call it the crest), which runs around the upper side of the head above the temples, at roughly forehead height, as a BCcampus barbering textbook and Avenue Five Institute’s fade guide for barber students describe it. A line at the ridge gives the classic undercut; a lower line gives a softer cut, and one well below the ridge is close to a taper with a long top. Above the ridge the long section narrows towards a strip along the top, so ask for that only if it is the look you want.
Our guide to taper and fade haircuts explains the fade heights and finishes for the blended version.
The undercut versions, and what to ask for
Slicked-back undercut, the classic
Four inches or more on top combed straight back with pomade, over a number 1 or 2 with a disconnected line; the 1930s and 1940s look that the 2010s revival copied.
The minimum differs by source; Wahl’s guide asks for a top section “at least 5 inches in length to slick back or sweep to one side”, while the Book of Barbering keeps at least three to four inches on top for its traditional slicked-back undercut.
Ask for “a disconnected undercut, number one on the sides, five inches on top, slicked back”.
Side-swept undercut, the everyday version
Three to four inches on top, the Book of Barbering’s medium length, swept to one side from a parting, with the sides at a number 2 and the line blended or left; the version that reads as a haircut rather than a statement.
Ask the barber for “an undercut, number two on the sides, blended, four inches on top, parted on the left”.
Short textured undercut, with less to style
Up to about two inches on top, the Book of Barbering’s short undercut, point-cut and pushed up or forward with matte clay, over a number 1 or 2; the undercut for men who will not blow-dry.
Ask for “a short undercut, number one on the sides, an inch and a half on top, textured”.
For long hair, the long undercut (the man bun undercut)
Six inches or more on top, up to shoulder length in the Book of Barbering’s long version, worn back, tied or loose, over clipped sides; the sides are what make the length wearable, because the weight is gone.
At the barber, ask for “an undercut, number one on the sides, leave the top, disconnected”.
Faded undercut, the softer option
Any of the tops above with the sides faded from a number 1 or skin at the bottom up to the line, so there is no hard edge; the Book of Barbering’s author says that when a client asks for an undercut he almost always recommends adding at least a subtle fade “to make the grow-out period more forgiving”.
Ask for “an undercut with a low skin fade, blended into the top, four inches on top”.
Face shape, hair type and hairline
The Book of Barbering’s position is that “the undercut works with every hair type and face shape”, and that “picking the right variation for your features is what makes it look good”; the variation is the whole decision.
A round face suits the versions with height (short textured, slicked back with lift) and a line kept at the ridge, so the sides narrow the face and the top lengthens it.
A long face suits the side-swept version with the line kept lower and the top flatter; a tall slicked-back undercut on a long face adds height it does not need.
Oval faces can wear “virtually any undercut style”, in the Book of Barbering’s words, and it suggests textured tops to soften a square face.
Thick and straight hair take the slicked-back and side-swept versions; wavy hair suits the textured and side-swept ones; curly hair suits a short textured undercut with the curl left on top; fine hair holds a short textured undercut more easily than a five-inch slick.
With a receding hairline, the slicked-back version pulls the hair off the corners and shows them; the short textured or side-swept versions, with the front left forward, show them less, and our guide to haircuts for a receding hairline covers which cuts work.
A beard can go with any version; with clipped sides, a beard faded at the cheek joins the two, and the beard styles guide and the face shapes guide cover the proportions.
What to tell the barber
The order has three parts, and the Book of Barbering names them as “the guard number for the sides”, “the length on top in inches”, and “whether you want a disconnected or faded transition”.
Add the line, either “at the ridge” or “a little lower”, and, for a parting, which side.
A complete order reads “a disconnected undercut, number two on the sides up to the ridge, four inches on top, parted on the left.”
Bring a photograph, from the front and the side if you can; the Book of Barbering’s claim is that a reference photo “eliminates 90% of miscommunication”.
For reference, the guard sizes on Wahl’s combs are a number 1 at an eighth of an inch (3 mm) and a number 2 at a quarter inch (6 mm), the two lengths Wahl’s undercut guide uses for the sides; numbering and printed lengths vary between makers and ranges, so read the markings on your own combs.
For the cuts next to the undercut, see the Ivy League and the men’s haircuts hub.
How to style an undercut
The sides need nothing; the top is styled by version.
For the slicked-back version, towel-dry, comb a pomade through from front to back, then comb again with a fine comb and let it set; a blow-dryer aimed back first gives a cleaner line, and Wahl’s guide finishes with a dab of pomade, styled to the side if parted or straight back. A water-based pomade usually rinses out in a normal wash, while an oil-based one generally takes repeated washes or a clarifying shampoo; our guide to hair products for men covers hold and shine, which vary with the formula.
To style it side-swept, blow-dry the top over to the parting side with a brush, then a light pomade or cream combed through, with the fingers to soften the front.
A short textured top takes matte clay on dry hair, worked in with the fingers and pushed up or forward; no comb.
The long version takes a leave-in conditioner or a light cream and a tie, or is worn down with the sides clean.
How often to cut it
The sides every two to three weeks, the interval the Book of Barbering gives “to keep the sides looking fresh and the contrast sharp”; the top every four to six weeks, its typical range, or longer if you are growing it.
A disconnected undercut grows out less gracefully, because the line softens into a shelf; the Book of Barbering calls faded undercuts “the most forgiving for grow-out”, which is the practical argument for the blend.
Between barber visits, a trimmer on the neckline keeps the outline tidy; re-cutting the sides up to the line is barber work, and our guide to cutting your own hair sets out what is realistic at home, a one-length buzz and a two-guard cut with a softened join.
Common questions
What is an undercut haircut for guys?
Short sides and back at one clipper length with a long top and a visible line between them; the fade blends the two, the undercut does not, and a faded undercut keeps the long top but blends the sides up into it.
Should I get a fade or an undercut?
An undercut if you want the contrast, the line and a long top to style; a fade if you want the sides to blend and to grow out gently; a faded undercut if you want most of the contrast without the shelf.
How far up should an undercut go?
For the classic look, to the parietal ridge, the widest point of the head (barbers also call it the crest), which runs around the upper side of the head above the temples, at roughly forehead height; lower for a softer cut, and above the ridge only if you want the long section narrowed towards a strip along the top.
Is the undercut still in style?
That is a matter of taste. Wikipedia records its revival in the early 2010s, and the Book of Barbering, updated in October 2026, still lists 23 versions; if the hard-line slicked-back version feels dated to you, a faded or short textured undercut is the quieter choice.
Undercut or crew cut?
A crew cut if you want a short top and tapered sides with no line; an undercut if you want a long top and short sides with one.
Sources checked for this article (12 September 2026, re-checked 12 October 2026)
Wikipedia, Undercut (hairstyle), https://en.wikipedia.org/wiki/Undercut_(hairstyle)
Book of Barbering, 23 undercut hairstyles for men that never go out of style, Khamis Maiouf, updated 4 October 2026, https://bookofbarbering.com/undercut-hairstyles-men/
Wahl USA, How to do an undercut, https://wahlusa.com/how-to/haircutting/mens-haircuts/undercut
Wahl USA, attachment comb length chart (instruction sheet), https://wahlusa.com/amfile/file/download/file/1074/product/909/
Arden Magtiza and Gary Franceschini, Barbering Techniques for Hairstylists (BCcampus open textbook, 2021), glossary entry “parietal”, https://opentextbc.ca/barberingtechniquesforhairstylists/back-matter/glossary/
Avenue Five Institute, Fading hair 101: a beginner’s guide for barber students, updated 26 February 2025, https://www.avenuefive.edu/barber-students-guide-to-fades/