Beard lengths are measured in millimeters (mm) or inches from the skin to the tip of the longest hair, and they range from 1 mm (stubble) to 25 mm and beyond (long, full beards). The length you choose drives everything else: which guard you clip on, how often you trim, and which styles even fit your face.
TL;DR
- 1–3 mm = stubble, 5–10 mm = short beard, 15–20 mm = medium beard, 25 mm+ = long beard (approximate bands used on this page; barbers and other guides draw the lines slightly differently).
- At the commonly quoted planning figure of ½ inch (12.7 mm) per month (≈0.42 mm/day, the planning figure used across our guides), 10 mm takes about 3½ weeks and 20 mm about 7 weeks from clean-shaven. Your own rate may differ.
- Clipper guards are numbered in eighths of an inch: #1 = 3 mm, #3 = 10 mm, #8 = 25 mm on Wahl's guide combs. Beard trimmers are usually labeled in mm instead.
- Always trim a dry beard with the grain, using labeled guards, and check symmetry with a comb and mirror.
- Match length to face shape: shorter for round faces, longer for square faces, and fuller sides with a moderate chin for rectangular faces.
- Preview a goatee or beard style on your own photo before you commit to a new shape.
Beard Length Chart: MM, Inches, Guard Number and Days to Grow
Use this chart to translate between millimeters, inches, clipper guard numbers and the style names barbers use. The guard numbers are Wahl's published guide-comb sizes (#1 = ⅛"/3 mm up to #8 = 1"/25 mm) from printed pages 5–6 of Wahl's Home Haircutting Made Simple guide (PDF, checked November 7, 2026). The last column is our own arithmetic: length ÷ 0.42 mm/day, starting from a clean shave. Rows marked "no standard guard" are lengths people search for that fall between Wahl comb sizes.
| Length (mm) | Length (in) | Clipper guard (Wahl) | Common name | Days to grow (≈0.42 mm/day) |
|---|---|---|---|---|
| 0.5–1 mm | 0.02–0.04" | No guard (trimmer at 0.5–1 mm) | Light stubble / five o'clock shadow | 1–2 |
| 3 mm | ⅛" | #1 | Stubble | 7 |
| 6 mm | ¼" | #2 | Short beard, tight | 14 |
| 10 mm | ⅜" | #3 | Short beard (short boxed length) | 24 |
| 13 mm | ½" | #4 | Short-to-medium beard | 31 |
| 15 mm | 0.59" | No standard guard (between #4 and #5) | Medium beard | 36 |
| 16 mm | ⅝" | #5 | Medium beard | 38 |
| 19 mm | ¾" | #6 | Medium beard, fuller | 45 |
| 20 mm | 0.79" | No standard guard (just over #6) | Medium beard, fuller | 48 |
| 22 mm | ⅞" | #7 | Medium-long beard | 52 |
| 25 mm | 1" | #8 | Long beard begins | 60 |
| 30 mm+ | 1.2"+ | #10 (31 mm) / #12 (38 mm), or scissors | Full, long beard | 71+ |
Guard number vs. mm label. Clipper guards count in eighths of an inch, so the mm figures are Wahl's rounded labels (⅜" is printed as 10 mm, though it is about 9.5 mm). The same Wahl guide also lists longer #10 (31 mm) and #12 (38 mm) combs. Most beard trimmers skip the numbers and print the cut length in mm on the comb. Other brands number differently, so read the length printed on your guard or in its manual rather than trusting the number alone. Exact conversions: ¼" is 6.35 mm and 1" is 25.4 mm; the guard labels round these to 6 and 25 mm.
Your growth rate changes the days column. 0.42 mm/day is the commonly quoted ½-inch-per-month figure that our guides use as a planning assumption, not a measurement of you. To get your own rate, shave one cheek, wait 7 days, comb the hair flat and measure it: for example, 2.1 mm after a week means 0.3 mm/day, so you would multiply the days above by about 1.4 (0.42 ÷ 0.30). Growth can also vary by season; a small study of 14 men in Sheffield, UK found beard growth lowest in January–February and highest around July (Randall & Ebling, 1991).
How to measure accurately. Comb the beard straight down, then hold a ruler against the skin at the chin and read the length at the longest tip. For a quicker check, run a trimmer with a known guard over one small patch and compare the result to the chart.
Beard Lengths in MM and Guard Numbers: What Each Length Looks Like
1 mm (trimmer, no guard). Barely more than five o'clock shadow. It reads as deliberate stubble and needs trimming every 2–3 days to stay even.
3 mm (#1). Visible, uniform stubble that softens the jawline without hiding it. It is usually the shortest length that still reads as intentional rather than unshaven.
5–6 mm (#2). The entry point to a short beard, where growth starts to read as a beard rather than stubble. It is also a common length for blending the neckline on longer beards.
10 mm (#3). A classic short beard, often called a "number 3 beard." On dense growth the chin and jaw read as filled in while the outline stays tidy; on finer or patchy growth some skin can still show. It is a common reference length for a short boxed beard, which typically sits around #2–#4 (6–13 mm).
13 mm (#4). Noticeable bulk. Many barbers leave the chin at #4 and take the cheeks down to #2 or #3 so the face doesn't look wider.
15–19 mm (#5–#6). Medium territory. The beard now has visible bulk, so cheek and neck lines matter more — see our guide to beard styles for outline options.
20–25 mm (#6–#8). A full, rounded medium-long beard. A "number 8 beard" (25 mm, 1 inch) is the longest comb in the standard #1–#8 set; Wahl also makes #10 and #12 combs, but many people switch to scissors from here and leave the chin longer than the cheeks.
30 mm+. Long beard. It requires regular washing and conditioning, and it changes your face's proportions the most.
Face shape and growth change the look. A 10 mm beard on a narrow face reads fuller than the same length on a wide jaw. Coarse, curly hair looks thicker at short lengths; fine, straight hair looks thinner until it gains length. Growth patterns matter too — a patchy goatee can look fuller at 5 mm than at 15 mm, because longer hair exposes the gaps.
Guard sizes map to millimeters. Beard trimmer guards are usually labeled in mm (1, 2, 3, 5, 7, 10 mm and up), while clipper guards use numbers (#1 = 3 mm, #2 = 6 mm, #3 = 10 mm on Wahl combs). If a guard has no marking, check the model's manual or the manufacturer's guard chart before relying on it for an exact length.
How to Trim Your Beard to Your Desired Length
- Start clean and dry. Wash and fully dry the beard. Wet hair stretches and appears longer, which leads to over-trimming.
- Comb it out. Comb in the direction the hair grows so all strands sit at their true length.
- Set your guard. Pick the guard matching your target from the chart above. When in doubt, start one size longer.
- Trim with the grain. Move the trimmer in the direction of hair growth, in slow, overlapping passes. Cutting against the grain removes more than you intend.
- Work from the sides to the chin. Do the longer areas last so you can judge the overall shape.
- Check symmetry. Look straight into a mirror, then turn your head side to side. Ask someone to check the back of the jawline if you can.
- Finish the details. Define the neckline just above the Adam's apple, keep the cheek line natural, and trim the mustache along the upper lip.
Tools you need: a trimmer with labeled guards, a fine-tooth comb, small scissors for stray hairs, and a well-lit mirror. Our roundup of goatee trimming tools covers what each tool is actually for.
Common mistakes to avoid: trimming a wet beard, removing the neckline too high, cutting both sides "to match" instead of measuring, and skipping the guard on a first pass. Each one costs weeks of regrowth.
Grow-In Times for 29 Goatee Styles, Converted to MM
Every style page in the Goatee.io library lists an estimated grow-in time: how long to let the hair grow before there is enough to shape that style. We converted all 29 of those estimates into an approximate length using the same planning assumption as the chart above (days × 0.42 mm). The result is a conversion of our own editorial estimates, not measurements of finished beards.
| Grow-in time | ≈ Length | Styles |
|---|---|---|
| 3–5 days | 1–2 mm (no guard) | Designer Stubble Goatee |
| 1–2 weeks | 3–6 mm (#1–#2) | Soul Patch |
| 2–3 weeks | 6–9 mm (#2–#3) | Petite Goatee, Corporate Goatee |
| 2–4 weeks | 6–12 mm (#2–#4) | Classic Goatee, Goatee with Stubble (chin section; the surrounding stubble takes 3–5 days), Musketeer, Rap Industry |
| 3–4 weeks | 9–12 mm (#3–#4) | Circle Beard, Disconnected, Rounded, Boxed |
| 3–5 weeks | 9–15 mm (#3–#5) | Full Goatee, Chin Strap + Goatee, Modern Goatee |
| 3–6 weeks | 9–18 mm (#3–#6) | Natural Goatee |
| 4–6 weeks | 12–18 mm (#4–#6) | Van Dyke, Anchor, Extended Goatee, Balbo, Pointed Chin, Tapered, Sculpted |
| 6–8 weeks | 18–24 mm (#6–#8) | Sharp Ducktail |
| 2–3 months | ≈25–38 mm (#8–#12 or scissors) | Handlebar Goatee, Ducktail Goatee, Imperial Goatee |
| 3–6 months | ≈38–76 mm (scissors) | Long Goatee, French Fork |
How to read it. Months are counted as 30 days, and guard numbers are the nearest Wahl comb range, not exact equivalents. In the library, 12 of the 29 styles have estimates that convert to 12 mm or less (#4 or shorter), 11 convert to ranges that reach 15–18 mm (#5–#6), and 6 have converted ranges that start at about 18 mm or more, including the 5 long styles that take two months or longer. If you grow slower than 0.42 mm/day, add time in proportion. For a style-specific example, the Van Dyke beard guide breaks the same arithmetic down by zone, from a 6 mm short chin patch to a 50 mm extended point, with a printable trim sheet.
Choosing the Right Beard Length for Your Face Shape
Round face. Go shorter — 3–10 mm — and keep the sides tight. Extra bulk at the cheeks widens the face further.
Oval face. Most lengths work. 10–20 mm adds definition without distorting your natural proportions.
Square face. Longer lengths suit you: 15–25 mm softens a strong jawline instead of emphasizing it.
Rectangular face. A medium 10–15 mm beard with fuller sides balances a longer face. Avoid very long chin hair, which stretches the face further.
Heart face. A medium beard with slightly more volume at the chin evens out a wider forehead.
A specific example: if you have a round face and want a goatee rather than a full beard, the goatee face shape guide walks through which chin shapes add length. For a broader look at beard categories, see the beard styles overview.
Beard Trimming Schedule and Maintenance
How often to trim depends on your target length and your growth rate. At the ½-inch-per-month planning figure, here's a practical baseline:
- 1–3 mm stubble: every 2–3 days.
- 5–10 mm short beard: every 1–2 weeks.
- 15–20 mm medium beard: you add roughly 3 mm a week, so divide the room you have left by your daily growth: trimmed back to 15 mm with a 20 mm limit, that is 5 ÷ 0.42 ≈ 12 days before the next light pass. Touch up the neckline weekly.
- 25 mm+ long beard: reshape the outline every 2–4 weeks while letting the length continue, with regular split-end trimming.
Daily and weekly care. Wash with a beard-specific cleanser 2–3 times a week, condition after washing, and apply oil to the skin underneath rather than the hair tips. A dedicated beard oil for goatees keeps the skin from drying under short lengths, where the hair doesn't wick oil away from the face.
DIY versus barber. Trim at home for maintenance between cuts and for lengths under 10 mm. Book a barber when you're changing shape, defining a new cheek or neckline, or growing past 20 mm for the first time — a single bad line at that length takes weeks to correct.
Preview Goatee Styles on Your Own Photo
A length decision is usually a style decision too: a Corporate Goatee (2–3 weeks) and a Van Dyke (4–6 weeks) need very different grow-in times. Goatee.io's AI goatee generator lets you upload a photo and preview a chosen style on your own face before you spend weeks growing toward it.
How it works: upload a clear, front-facing photo, pick a style from the library, and compare results. The tool works by style, not by length: there is no millimeter slider, so use the tables above to estimate how long the style you like takes to grow.
When to use it: before switching styles or when you're deciding between a short and a longer shape. It's a preview, not a guarantee — your hair texture and density still affect the final result.
FAQ
What is the most attractive beard length?
In a 2013 University of New South Wales study led by Barnaby Dixson, women rated faces with heavy stubble, about 10 days of growth, as the most attractive (UNSW news release). At this page's 0.42 mm/day planning assumption, 10 days is roughly 4 mm, between a #1 and a #2 guard (our conversion, not a figure from the study). The same paper also measured perceived health, masculinity and parenting ability, and men rated full beards about as highly as heavy stubble, so "most attractive" depends on who is judging and what for (Dixson & Brooks, 2013). It is a single study with a small set of faces; in practice, pick the length that suits your face shape and your growth density.
How do I know what mm my beard trimmer guard is?
Beard trimmer guards are labeled with their cut length in millimeters — common sizes are 1, 2, 3, 5, 7, and 10 mm. Clipper guards use numbers instead: on Wahl combs #1 is 3 mm, #2 is 6 mm, #3 is 10 mm, #4 is 13 mm and #8 is 25 mm. If a guard has no marking, check the model's manual or the manufacturer's guard chart.
How long does it take to grow a beard of a certain length?
Using the commonly quoted planning figure of about ½ inch (12.7 mm) per month (about 0.42 mm a day), 10 mm takes about 3½ weeks (24 days), 20 mm about 7 weeks (48 days), and 30 mm around 10 weeks (71 days). Individual growth rates vary, so treat these as estimates.
Should I trim my beard wet or dry?
Trim dry. Wet hair stretches and looks longer than it is, which makes it easy to cut more than you planned. Dry trimming gives you an accurate read on your actual length.
What does a number 3 beard look like?
A #3 clipper guard leaves about 10 mm (⅜ inch). That is a classic short beard: with dense growth the chin and jaw look filled in and the outline stays tidy, while finer or patchy growth may still show some skin. It is a common reference length for a short boxed beard.
What is the difference between beard length and beard style?
Length is a measurement — how many millimeters of hair you have. Style is the shape and outline, such as a goatee, Balbo, or full beard. Length limits which styles are available: you can't shape a defined goatee at 1 mm.
Sources
- Wahl Clipper Corporation. Home Haircutting Made Simple, guide-comb sizes on printed pages 5–6. PDF (checked November 7, 2026).
- UNSW Sydney. "Study finds men most attractive with heavy-stubble," news release, 29 April 2013. unsw.edu.au
- Dixson BJ, Brooks RC. "The role of facial hair in women's perceptions of men's attractiveness, health, masculinity and parenting abilities." Evolution and Human Behavior, 2013;34(3):236–241. DOI link
- Randall VA, Ebling FJ. "Seasonal changes in human hair growth." British Journal of Dermatology, 1991;124(2):146–151. PubMed 2003996
- Days-to-grow figures and the style-length table are our own arithmetic (length ÷ 0.42 mm/day; days × 0.42, months counted as 30 days), using the grow-in times listed on all 29 Goatee.io style pages as of November 7, 2026. The 0.42 mm/day input is the commonly quoted ½-inch-per-month figure, used here as a planning assumption rather than a measured average.
Try the Goatee.io generator — upload a photo and preview goatee styles on your own face. HD renders are sold as one-time credit packs, with regular packs starting at $4.90 and no subscription (see pricing; checked November 7, 2026).