Beard trimmer guards explained
A #2 on one trimmer is not a #2 on another. Here is what the numbering actually means, and the one rule that saves most home trims.
By Sawyer V. · Published
We have not tested any of this. Everything below is compiled from published manufacturer specifications, and the arithmetic is printed so you can check it. This page carries affiliate links: if you buy through one we earn a commission at no extra cost to you, and it does not change the order of the picks. Full disclosure.
The short version
The number is how much hair is left standing, not how much is removed. A lower number cuts shorter. Numbers are not standardized between brands - a #2 is roughly 6 mm on a clipper-style scale and can be something else entirely on a trimmer with a dial. Always check the millimeter figure, and always start two numbers longer than you think you want.
| # | Pick | Lasts | Score | Price |
|---|---|---|---|---|
| 1 | Wahl Aqua Blade Coarse hair and long gaps between charges | 1,300 shaves* | 7.9/10 | Check price on Amazon |
| 2 | Panasonic ER-GB80 Precise, repeatable stubble | 1,300 shaves* | 7.3/10 | Check price on Amazon |
| 3 | Philips Norelco OneBlade 360 Trimming, edging and shaving with one blade | 1,300 shaves* | 7.1/10 | Check price on Amazon |
No live price is currently verified, so every button here reads Check price instead of a number we cannot stand behind. Why we do it that way.
What the number actually means
The number is the length of hair the guard leaves standing, measured from the skin. It is not how much the trimmer removes. So a #1 leaves less than a #4, and going down a number cuts shorter.
That sounds obvious written down and it is reliably the first thing people get backwards under pressure with a trimmer in their hand.
The traditional clipper scale
| Guard | Approximate length | Reads as |
|---|---|---|
| #1 | 3 mm (1/8 in) | Very short, skin visible |
| #2 | 6 mm (1/4 in) | Short beard |
| #3 | 9.5 mm (3/8 in) | Short but clearly a beard |
| #4 | 12.5 mm (1/2 in) | Medium |
| #5 | 16 mm (5/8 in) | Medium to long |
| #6 | 19 mm (3/4 in) | Long |
| #8 | 25 mm (1 in) | The longest most trimmers reach |
Below #1 the scale runs out, which is why it is a poor system for beards: stubble lives between 1 and 5 mm, and the numbered scale has almost no resolution down there.
Why brands disagree
Because nobody ever agreed a standard, and modern beard trimmers have largely abandoned the numbered convention in favor of dials calibrated directly in millimeters.
- Panasonic publishes 39 settings from 0.5 to 20 mm across three combs. There are no numbers, only lengths.
- Wahl publishes a 0.2 to 25 mm range across sixteen guide combs - a numbered set, but with a range that extends well below where the traditional scale begins.
- Philips OneBlade publishes five comb settings at 1, 2, 3 and 5 mm plus 0.2 mm bare-blade. Five lengths, no numbers.
The practical consequence: the number that transfers between tools is the millimeter figure, not the guard number. Write down the millimeters you like rather than the number, and you will still know your length when you replace the trimmer.
The same numbers, on a head
Clipper guards use the same convention and the same eighth-inch steps, which is why this page is the closest thing we currently have to a hair guide - the hair section is reserved and honest about being unbuilt. Two differences worth knowing when the numbers move from a face to a scalp:
- The steps are coarse for a beard and about right for a scalp, because scalp lengths vary over a wider range.
- A clipper blade is wider, so the same number covers more area per pass and is harder to be precise with along a line. The head-to-head covers where each tool belongs.
Using a guard properly
Hold it flat against the skin. Tilting the comb away from the face leaves the hair longer than the number says, which is how one side of a beard ends up longer than the other - the wrist angle differs between your dominant and non-dominant hand and you do not notice.
Move against the direction of growth in short strokes and cover each area from two directions. The trimming guide has the full seven-step sequence, including where the neck line goes - which matters more to how a beard reads than any guard number does.
Every pick, with the working
Each entry shows the published specifications, the axis scores they produce and what you give up. The order is the computed order, not a commercial one, and the arithmetic is open underneath every score.
Our pickCoarse hair and long gaps between charges
Wahl Aqua Blade
180 minutes of runtime from a 60-minute charge, a published 0.2 to 25 mm cutting range, 16 guide combs, fully waterproof, and a five-year warranty with a lifetime blade warranty behind it. On coarse or dense hair the extra motor headroom and the wider guard range are what you notice.
- Runtime
- 180 min
- Charge time
- 60 min
- Length settings
- 16
- Cutting range
- 0.2 - 25 mm
- Waterproof
- Yes
- Made in
- Not published
- Refill
- Proprietary to the maker
- Warranty
- 5 years, plus lifetime blade warranty
- Assumed service life
- 1,300 uses
The arithmetic: 260 uses a year x 5 years of assumed service life = 1300 uses.
What it gets right
- 180 minutes of published runtime — by a distance the longest here — and 3 minutes from a 1-minute charge
- 0.2 to 25 mm published cutting range, the widest in this ledger
- Fully waterproof and rinseable
- 5-year warranty plus a lifetime blade warranty, published by Wahl
Flaws
- 16 guide combs is a drawer's worth of plastic
- Model numbering across the 9899 family is confusing; variants differ in what is in the box
The working behind the 7.9
- How long it lasts: not scored
- Not scored. This is a durable item, not a consumable, so how long it lasts is an assumption about service life rather than something the pack size tells us.
- Ease of switching: 9.0
- 180 minutes of published runtime and a 1-minute quick charge mean the battery never enters the decision (++), waterproof (+), widest published length range here (+), 16 combs to store (-).
- Refill economics: 4.0
- Only this maker's refill fits, so the ongoing price is set by the maker rather than by a market. This is where the real cost of ownership hides.
- What the maker publishes: 10.0
- 7 of 7 specifications a buyer would expect are published: runtimeMin, chargeMin, minLengthMm, maxLengthMm, settings, waterproof, warrantyLabel. 7 / 7 x 10 = 10.0.
Axes with no published input are dropped and the remaining weights re-normalized, so a product is not punished for a category where an axis does not apply. Specifications compiled 3 September 2026 from Wahl Aqua Blade published specifications.
2Precise, repeatable stubble
Panasonic ER-GB80
39 length settings from 0.5 to 20 mm across three comb attachments, 45-degree stainless blades, 50 minutes of runtime from a one-hour charge, and it is washable. If you keep a specific stubble length rather than a beard, this is the trimmer that lets you find the exact number and return to it.
- Runtime
- 50 min
- Charge time
- 60 min
- Length settings
- 39
- Cutting range
- 0.5 - 20 mm
- Waterproof
- Yes
- Made in
- Not published
- Refill
- Proprietary to the maker
- Warranty
- Not published
- Assumed service life
- 1,300 uses
The arithmetic: 260 uses a year x 5 years of assumed service life = 1300 uses.
What it gets right
- 39 published length settings from 0.5 mm to 20 mm — the finest increments here
- 45-degree stainless blades, published by Panasonic
- Washable, and usable corded when the battery is flat
- 50 minutes of runtime from a 1-hour charge
Flaws
- 50 minutes is the shortest runtime of the trimmers here
- 39 settings is a lot of dial to turn if you only ever use one
- No foil shaver in the box, so it will not take you to bare skin
The working behind the 7.3
- How long it lasts: not scored
- Not scored. This is a durable item, not a consumable, so how long it lasts is an assumption about service life rather than something the pack size tells us.
- Ease of switching: 8.5
- 39 published settings from 0.5 mm mean a length you like is a number you can write down and repeat (++), washable (+), 50 minutes is the shortest runtime here (-).
- Refill economics: 4.0
- Only this maker's refill fits, so the ongoing price is set by the maker rather than by a market. This is where the real cost of ownership hides.
- What the maker publishes: 8.6
- 6 of 7 specifications a buyer would expect are published: runtimeMin, chargeMin, minLengthMm, maxLengthMm, settings, waterproof. Not published: warrantyLabel. 6 / 7 x 10 = 8.6.
Axes with no published input are dropped and the remaining weights re-normalized, so a product is not punished for a category where an axis does not apply. Specifications compiled 3 September 2026 from Panasonic ER-GB80 published specifications.
3Trimming, edging and shaving with one blade
Philips Norelco OneBlade 360
Not a shaver and not a trimmer: a single oscillating blade that trims with a comb, edges without one and takes stubble down close without ever going properly bare. 45 minutes of runtime, five comb lengths from 0.2 to 5 mm, waterproof, and Philips publishes a four-month blade life with an indicator that tells you when it is up.
- Runtime
- 45 min
- Charge time
- Not published
- Length settings
- 5
- Cutting range
- 0.2 - 5 mm
- Head replacement
- Every 4 months
- Waterproof
- Yes
- Made in
- Not published
- Refill
- Proprietary to the maker
- Warranty
- Not published
- Assumed service life
- 1,300 uses
The arithmetic: 260 uses a year x 5 years of assumed service life = 1300 uses.
What it gets right
- Published four-month blade life with a wear indicator on the blade itself
- Five comb settings from 0.2 mm to 5 mm plus bare-blade edging
- 45-minute runtime, 100% waterproof, usable in the shower
- The cheapest entry point to a powered shave here by a wide margin
Flaws
- It will not give you a properly bare shave; that is a design decision, not a fault
- Proprietary blades, replaced on a schedule, which is the real cost of ownership
- 45 minutes of runtime
The working behind the 7.1
- How long it lasts: not scored
- Not scored. This is a durable item, not a consumable, so how long it lasts is an assumption about service life rather than something the pack size tells us.
- Ease of switching: 9.5
- Published 4-month blade life with an indicator, so the one maintenance decision is made for you (++), waterproof and shower-usable (+), five published comb lengths (+), proprietary blades on a schedule (-).
- Refill economics: 4.0
- Only this maker's refill fits, so the ongoing price is set by the maker rather than by a market. This is where the real cost of ownership hides.
- What the maker publishes: 6.0
- 3 of 5 specifications a buyer would expect are published: runtimeMin, waterproof, headReplacementMonths. Not published: chargeMin, cuttingElements. 3 / 5 x 10 = 6.0.
Axes with no published input are dropped and the remaining weights re-normalized, so a product is not punished for a category where an axis does not apply. Specifications compiled 3 September 2026 from Philips Norelco OneBlade 360 published specifications.
No live price is currently verified, so every button here reads Check price instead of a number we cannot stand behind. Why we do it that way.
Questions people actually ask
What length is a number 2 guard?
On the traditional clipper scale, about 6 mm - the numbers run in eighths of an inch, so #1 is roughly 3 mm, #2 is 6 mm, #3 is 9.5 mm and so on. But that scale is a convention rather than a standard, and trimmers with a dial rather than numbered combs do not follow it at all. Check the millimeter figure on your own tool.
Why are guard numbers different between brands?
Because there is no standard. The eighth-of-an-inch clipper convention is widely followed for clipper combs and widely ignored for beard trimmers, which increasingly use a dial calibrated in millimeters instead. Panasonic publishes 39 settings from 0.5 to 20 mm; Wahl publishes a 0.2 to 25 mm range across 16 combs. Neither uses the numbered scale.
What guard should I use for stubble?
Designer stubble is roughly 1 to 3 mm and heavy stubble roughly 3 to 5 mm, which on the clipper scale is below #1. This is exactly why a trimmer with fine millimeter increments beats one with numbered combs for stubble - that roundup covers it.
Can I use a longer guard to fade a beard?
Yes, and it is the standard method: trim the whole beard at your chosen length, then go one or two numbers shorter on the area below the jaw, blending upwards with the trimmer angled away from the skin. Do the length first - the fade is the last step, not the first.