Clipper Guard & Blade Number Size Chart for Professional Barbers

Quick answer: A clipper blade number is standardized industry-wide (a #10 blade cuts the same length on an Andis, a Wahl, or an Oster, under what the trade calls the A5 Universal Standard), but a guard comb number is not. A Wahl #0.5 guard leaves hair about 1.5mm long, while an Andis #0.5 guard leaves it closer to 2.4mm, roughly a 0.9mm gap for the exact same nominal number. If you're stacking guards across brands or buying a universal comb set, that gap is the number that actually matters. Below is the brand-by-brand breakdown, plus the three guide comb sets we carry and where each one fits.

Why this trips up even experienced barbers

Most barbers learn guard numbers the way they learn anything on the job: by feel, on one brand's clippers, for years. That works fine until a new hire brings their own Andis guards to a Wahl-based station, or a shop switches suppliers and assumes "#1 is #1." It usually isn't. Blade numbering got standardized decades ago because the blade sits inside a fixed housing with a fixed geometry, so the industry converged on one scale. Guard combs are a separate, external, snap-on accessory that each manufacturer designed and numbered independently, with no governing body ever forcing agreement on what a given number means in millimeters. The result is a system where the numbers look consistent across brands and are not.

Guard number by brand: the confirmed comparison

This is the part most size charts get wrong by publishing a single "universal" mm column. There isn't one. Here is what we can confirm from manufacturer specs, brand by brand, without inventing numbers for gaps we can't verify:

Accuracy note before you read the table: the mm equivalents below are commonly cited industry figures, not a single official cross-brand standard, and they can vary slightly by manufacturer, product line, and even production batch. There is no governing body that standardizes guard-comb millimeter equivalents the way blade numbers are standardized under the A5 Universal Standard. Always check the number stamped on your specific guard, or the spec sheet that shipped with it, before relying on a chart like this for a paying client's first cut.

The one row we can point to across two brands, #0.5, already makes the point: a roughly 0.9mm gap between Wahl and Andis for the identical nominal number is enough to change how a fresh fade actually looks, and that gap itself should be read as a commonly cited approximation rather than a lab-verified constant. We're not filling in the other cells with guesses. If your brand and guard number aren't in this table, treat the number as brand-specific and unconfirmed until you've checked the manufacturer's own listing.

Blade numbers are a different story: the A5 Universal Standard

Where guards are inconsistent, blades are the opposite. The industry's A5 Universal Standard means a given blade number cuts to the same finished length regardless of manufacturer, because the blade mounts directly to the clipper body rather than snapping on as an accessory. Wahl's own Competition Blade Series is a useful worked example of how granular that blade-side scale gets in practice: 00000 is 0.4mm, 0000 is 0.6mm, 000 is 0.8mm, 0A is 1.8mm, #1 is 2mm, #1A is 2.8mm, #1.5 is 3.8mm, #2 is 6mm, #3.5 is 8mm, and #3.75 is 10mm. That's a blade ladder, not a guard ladder, and it's worth keeping the two separate in your head. A #1 blade and a #1 guard are not related numbers measuring the same thing.

The Oster stacking example, worked through

Stacking a guide comb over a blade is common practice for reaching finished lengths a single blade or guard can't hit alone, and it's another place brand-specific math matters. Oster's own reference point: a #000 blade sits at 0.5mm, and stacking it with a #0 guide comb (1.5mm on its own) gets you to a 2mm total finished cut length. That's not addition by coincidence, it's how Oster's own spec sheet documents the pairing. The lesson generalizes: if you're stacking a guide comb over a blade to hit a specific finished length, confirm both numbers from the same manufacturer's own documentation rather than assuming a comb rated at one brand's "1.5mm" adds cleanly to a blade rated by a different brand's scale.

The Speed-O-Guide color system, for reference

Outside the Wahl/Andis/Oster brand numbers, a lot of the industry also references the Speed-O-Guide color-coded comb system, which uses fractions of an inch rather than brand-specific numbers: 000 is 1/32" (about 0.8mm), 00 is 1/16" (about 1.6mm), 0 is 3/16" (about 4.8mm), 0A is 5/16" (about 7.9mm), 1 is 7/16" (about 11.1mm), 1A is 9/16" (about 14.3mm), and 2 is 11/16" (about 17.5mm). This system exists specifically because it's brand-agnostic. If you regularly work across multiple clipper brands in the same shop, color-coded fractional combs sidestep the whole brand-numbering mismatch rather than trying to memorize three separate scales.

How to check your clipper's actual spec sheet

Don't trust the number stamped on the guard by itself. A few minutes of verification saves a bad first cut on a new client:

• Look for the manufacturer's printed spec sheet or product insert, most list the mm equivalent directly next to the guard number.
• If you're buying a universal or third-party guard set to use across brands, measure with calipers against a guard you already trust before using it on a paying client.
• When a listing says "fits most clipper brands," read that as a mechanical fit claim (it snaps onto the housing), not a guarantee that the cut length matches your other brand's same-numbered guard.
• Keep blade math and guard math separate. A stacked finished length is only reliable when both the blade and the guide comb come from the same manufacturer's documented pairing, as in the Oster example above.

Our pick: what we carry and where each fits

We carry three guide comb sets built for exactly this problem, sized for different shop needs:

• 8-Piece Universal Hair Clipper Guide Comb Set, fits most clipper brands, $14.99. Our budget pick for a shop that needs broad mechanical fit across brands. Treat "universal" here as fit, not identical mm output, and verify against the chart above before your first cut on an unfamiliar clipper.
• Hair Clipper Guide Combs, 1.5mm & 4.5mm Set of 2, $13.99. Our pick for a barber who wants two specific, known lengths rather than a full spread, useful as a tight, predictable pairing once you've confirmed those two numbers match your clipper's own spec.
• 8pcs/10pcs Universal Hair Clipper Limit Comb Guide Attachment Set, starting at $26.99. Our pick for a full-service station that needs the widest length spread in one set, at a price still well under buying brand-specific guards individually.

If you're setting up a new station from scratch rather than just restocking guards, our Professional Barber Clipper Startup Kit, $99.99, bundles a clipper with the accessories a new station needs. It's a starter bundle, not a standalone guard set, so pair it with one of the three guide comb sets above rather than treating it as your guard solution on its own.

The verdict

Blade numbers travel across brands. Guard numbers don't, not reliably, and the roughly 0.9mm Wahl-versus-Andis gap on the exact same "#0.5" is a real, meaningful difference, not a rounding error you can ignore, even though the specific figures above are commonly cited industry approximations rather than a single audited standard. Before you stack a guard from a set you didn't buy with your clipper, check the brand-specific mm figure, not just the number stamped on the plastic, and confirm it against your own unit's spec sheet when precision matters. For most working barbers, the 8pcs/10pcs universal set covers day-to-day range at a fair price, the 1.5mm & 4.5mm two-pack is the tight, predictable pairing worth keeping in a kit bag, and the 8-piece universal set is the sensible starting point if you're building your first guard collection.