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Quick answer: the Braun Series 9 BT9420 scores highest (4.8/5): 40 length settings in 0.5 mm steps with a lock, the longest runtime here (180 minutes) and combs that reach 20 mm for longer beards. For the finest control on short and medium beards, the Philips 9000 Prestige adjusts in 0.2 mm steps.
Braun Series 9 BT9420 Beard Trimmer
- 40 length settings in 0.5 mm steps, with a length lock
- Up to 180 minutes of cordless runtime
- 100% waterproof; comb reaches up to 20 mm
A beard trimmer earns its place by doing the same job well every time: the same length, evenly, without pulling. The details that make that possible are the length system (how many settings, how precise, whether they lock), the battery and how easy it is to clean. We compared three well-known premium beard trimmers — Braun’s Series 9 BT9420, the Philips Beard Trimmer 9000 Prestige and the Panasonic ER-SB40 — on their published specifications.
What matters when choosing a beard trimmer
Precision is about step size. The number of settings matters less than the gap between them. 0.2 mm steps let you fine-tune stubble and short beards; 0.5 mm steps are enough for most styles.
A length lock prevents mistakes. A dial or comb that shifts mid-trim can leave a patch shorter than the rest. Locking length systems stop that.
Maximum length matters for longer beards. Many trimmers stop at 10 mm. If you keep a fuller beard, look for combs that go further.
Waterproof means easier cleaning. Being able to rinse the trimmer under the tap keeps blades clean and hygienic.
Specifications side by side
Philips 9000 Prestige
Braun Series 9 BT9420
Panasonic ER-SB40
How we scored them
Each trimmer is rated from 1 to 5 on five comparison points, based on how its official specification compares with the other two. The overall score is the average. Cutting comfort and evenness can’t be measured from a spec sheet, so they aren’t part of the score. Read our full method.
| Comparison point | Philips 9000 Prestige | Braun Series 9 BT9420 | Panasonic ER-SB40 |
|---|---|---|---|
| Length settings Number of length settings you can choose. |
4/5 | 5/5 | 3/5 |
| Precision Size of the steps between settings — smaller steps mean finer control. |
5/5 | 4/5 | 3/5 |
| Battery runtime Rated cordless runtime on a full charge. |
4/5 | 5/5 | 2/5 |
| Water use Whether it can be rinsed or used wet. |
5/5 | 5/5 | 5/5 |
| Maximum length Longest beard length it can trim to. |
3/5 | 5/5 | 3/5 |
| Overall score (average) | 4.2/5 | 4.8/5 | 3.2/5 |
1. Braun Series 9 BT9420 — best overall (4.8/5)
Braun’s Series 9 BT9420 has the most complete length system here: 40 settings in 0.5 mm steps, with a lock so your chosen length can’t shift mid-trim. Its comb for longer beards covers 10.5–20 mm, so it handles fuller beards that other trimmers can’t. Braun rates the battery at up to 180 minutes of cordless runtime — the longest in this comparison — and the trimmer is 100% waterproof for rinsing.
Its steps are coarser than Philips’ 0.2 mm, and a German retailer lists a full recharge at about 150 minutes. Braun also sells the BT9420 as a kit with barbering tools in some markets — check what’s in the box where you buy.
Not for you if: you keep very short stubble and want the finest possible steps.
✔ Pros
- 40 settings with length lock
- Longest runtime (180 min)
- Reaches 20 mm for longer beards
- 100% waterproof
✘ Cons
- Coarser steps than Philips (0.5 mm)
- Long full recharge (about 150 min)
2. Philips Beard Trimmer 9000 Prestige — most precise (4.2/5)
The Philips 9000 Prestige offers 30 length settings from 0.4 to 10 mm in 0.2 mm steps — the finest in this comparison — set with a dial on the trimmer. It uses full metal blades with Philips’ SteelPrecision cutting system, runs for up to 120 minutes from a 1-hour charge (with a 5-minute quick charge for a fast trim), works corded or cordless, and is 100% waterproof for cleaning. It comes with a click-on comb for longer beards and a storage and travel case, plus a 2-year warranty.
Its built-in range stops at 10 mm, and some regional versions of the BT9810 are marked discontinued on Philips’ sites, so availability depends on your country.
Not for you if: you keep a beard longer than 10 mm.
✔ Pros
- Finest steps here (0.2 mm)
- 1-hour charge, 5-min quick charge
- Corded and cordless use
- Travel case included
✘ Cons
- Built-in range stops at 10 mm
- Availability varies by country
3. Panasonic ER-SB40 — simple and powerful (3.2/5)
Panasonic’s ER-SB40 keeps things simple: 19 length settings from 0.5 to 10 mm, set with a quick-adjust dial and a single comb. Its highlight is the motor — a linear motor rated at 9,800 cuts per minute, designed to power through thick, dense hair. It’s waterproof, can be used in the shower when unplugged, and works corded as well as cordless.
It scores lowest because of its 60-minute cordless runtime (the shortest here), fewer and coarser settings, and a 10 mm maximum. Panasonic lists it at US$134.99 on its US store.
Not for you if: you want many length options or long cordless sessions.
✔ Pros
- Linear motor, 9,800 cuts per minute
- Waterproof, usable in the shower
- Corded and cordless use
✘ Cons
- Shortest runtime here (60 min)
- Fewest settings (19)
- Stops at 10 mm
Which one should you buy?
- Medium to long beard: Braun Series 9 BT9420 (up to 20 mm).
- Stubble and short, precisely shaped beards: Philips 9000 Prestige (0.2 mm steps).
- Thick, dense hair and a simple routine: Panasonic ER-SB40.
- You travel a lot: Braun (180 min runtime) or Philips (travel case included).
Frequently asked questions
What’s the difference between a beard trimmer and a shaver?
A trimmer cuts hair to a set length using combs or guards; a shaver cuts hair at skin level for a clean shave. Some trimmers include a shaving attachment, but none of these three is designed as a shaver.
How often should I clean a beard trimmer?
Brush or rinse the blades after each use, and oil them occasionally if the manufacturer recommends it. All three trimmers here can be rinsed with water.
Which length is best for stubble?
Short stubble is usually around 1–3 mm and a fuller stubble 3–5 mm. Fine steps, such as Philips’ 0.2 mm, make it easier to find the exact look you want.
Can I use a beard trimmer on my head or body?
Beard trimmers are designed for facial hair. For body hair, a dedicated body groomer with skin-protection features is a better and safer choice.
Our verdict
The Braun Series 9 BT9420 is the most versatile trimmer on paper, with a locking 40-setting system, the longest runtime and room for longer beards. Choose the Philips 9000 Prestige for the most precise short-beard trimming, or the Panasonic ER-SB40 for a straightforward, powerful trimmer.
Sources
- Braun Australia — Series 9 BT9420 (settings, runtime, waterproofing, combs)
- Braun Shop Germany — BT9420 (charging time)
- Philips — Beard Trimmer 9000 Prestige specification sheet
- Philips UK — Beard Trimmer 9000 Prestige BT9810
- Panasonic — ER-SB40 specifications and price
Specifications checked on 10 October 2026. Prices vary by country and retailer.