A bob looks like the simplest cut on the floor and behaves like one of the least forgiving. The line is short, the perimeter is exposed at every angle, and there is nowhere for error to hide the way it can in longer layered work. This isn't a refresher on how to hold a blunt line steady — if you need that foundation, our troubleshooting guide to uneven blunt cuts and our piece on the order in which to learn haircutting techniques cover that ground. This is about what changes once you're building a bob specifically: sectioning strategy, how the client's own head shape and hang dictate the guideline, and the graduation decisions that separate a blunt bob from an A-line.
Sectioning: horizontal is a starting point, not a rule
Most stylists default to horizontal sections around the head, and for a true one-length blunt bob on a client with average head shape, that's correct. But a bob is rarely cut on "average" — occipital prominence, crown height, and neck taper all vary enough that horizontal sectioning can bake in error before you've touched the perimeter.
Two adjustments worth building into your sectioning habit:
- Slight diagonal-forward partings through the sides. When a client has a pronounced occipital bone, hair in that zone will want to sit higher than the sides once dry. Sectioning with a slight forward diagonal in the side panels — rather than a strict horizontal — lets you compensate for that lift before you ever cut, instead of discovering it after the blow-dry.
- Working section depth down as you approach the perimeter. Take thicker sections through the crown where you're establishing the interior guide, then thin your sections to no more than a quarter inch in the final passes along the hairline and nape. Bob perimeters read every deviation because there's no length below the line to disguise a step.
Let the head shape set the guideline, not the chair
A guideline cut with the head pulled forward and down — the default for establishing a nape-length blunt line — assumes the skull curves predictably from crown to nape. It often doesn't. A flatter occipital will cause the guideline to sit differently once the head returns to natural position than it appeared when stretched down and forward.
Before you commit to a final guideline on a bob, run your fingers along the client's actual head shape with the chin level, not tucked. Feel for where the skull curves away from the cutting line rather than trusting your eye alone. On clients with a flatter back skull, you'll often need to cut the guideline very slightly longer at center back than pure horizontal geometry suggests, so the finished line doesn't ride up once natural fall takes over.
Graduation: the real difference between a blunt bob and an A-line
The two bob families diverge almost entirely on elevation and graduation, and this is where a lot of "why does my bob look chunky at the back" complaints originate.
- Blunt bob: zero to near-zero elevation, cut on natural fall or with minimal lift, no internal graduation built into the interior. Every section should be cut with the same low elevation you used to establish the guideline — the moment you start lifting sections higher through the crown to "blend," you introduce graduation the client didn't ask for.
- A-line bob: intentional length increase from back to front, built either through diagonal-forward sectioning combined with a fixed guideline, or through slight elevation increase toward the front hairline. The graduation here should be controlled and gradual — a jump in elevation between adjacent sections is what produces a visible step rather than a smooth diagonal.
Shear selection matters more here than stylists often credit it for: a blunt bob wants a shear that gives you a clean, controlled line with minimal slippage at low elevation, while A-line work benefits from a blade geometry that stays stable through the gradual elevation changes without dragging. We go deeper on how blade design affects different cutting techniques in this piece on shears and technique, and you can browse the shears we build for this kind of precision work in our cutting shears collection.
Two pitfalls specific to bobs
Over-elevating at the back. It's tempting to lift sections slightly through the crown and back to "soften" what feels like a heavy line while you're mid-cut. On a blunt bob, this is almost always a mistake — it introduces graduation into a shape that's supposed to read as one continuous weight line, and the client will see a visible break once the cut dries and falls. If the back feels heavy, the fix is in your guideline placement and the head-shape check above, not in elevation you add on the fly.
Ignoring the ear-to-ear balance point. The point directly in front of the ear is where a bob's front length gets set, and it needs to match — or intentionally differ from, in an A-line — its mirror point on the other side before you finalize the back. Stylists who work the perimeter in one continuous sweep sometimes reach the front only to find the two sides don't land at the same point relative to the jaw. Check this balance point on both sides before you connect the back sections, not after.
Checking the line dry, in natural position
A bob that looks perfect wet and stretched can look completely different once it's dry and falling naturally — this is truer of bobs than almost any other cut because the shortness of the line leaves no room for shrinkage or wave pattern to average itself out along extra length. Always do a final dry check with the client's head in a neutral, natural position, not held or tilted by you. Comb the hair down with no tension and look at the line exactly as the client will see it in the mirror at home. Any residual step, especially around the balance points, shows up here even when it was invisible wet.