1 / 7Philips Sonicare DiamondClean Smart 9400 Electric Toothbrush, HX9918/89
HX9918: The Philips Sonicare DiamondClean Smart 9400 is a sonic electric toothbrush with app guidance, pressure feedback and four brushing modes. Three intensity levels, brush-head replacement reminders and a travel charging case add flexibility, while customer feedback raises concerns about durability and mixed battery experiences.
At a glance
- Choose from Clean, White+, Gum Health and Deep Clean+ modes, with three intensity levels.
- The handle's light ring alerts when brushing pressure is too high.
- The Philips Sonicare app offers personalised brushing guidance when connected.
- QuadPacer and SmarTimer support brushing across mouth sections and a recommended two-minute routine.
- The listing claims up to two weeks of battery life under its stated standard-mode brushing schedule.
Reference price: £449.99
Price checked: 12 Nov 2026
View offerAhead of Black FridayExplore the selectionOften bought together
Pros and cons
Pros
- Four named modes and three intensity levels let users vary their brushing routine.
- Pressure feedback, app guidance and brush-head replacement reminders provide practical brushing prompts.
- The stated set includes four brush heads, a USB charging travel case and a charging glass with stand.
Technical specifications
14 specifications| Brand | PHILIPS |
|---|---|
| Model | Philips Sonicare DiamondClean Smart 9400 |
| Weight listed | 1.08 Kilograms |
|---|
| Bluetooth connectivity | Bluetooth Connectivity |
|---|---|
| Brushing timer and pacing | Brushing Timer, Bluetooth Connectivity, QuadPacer |
| Sonic movement rate | 62,000 bristle movements per minute |
| Battery life claim | up to two weeks on a single charge (based on two periods of two-minute brushings per day on standard mode) |
|---|---|
| Travel charging | USB charging travel case |
| Home charging | charging glass and stand |
| Bathroom plug | UK 2-Pin bathroom plug |
| Colour | Black |
|---|---|
| Toothbrush head shape | Oval |
| Bristle material | Nylon |
| Handle material | Plastic |
What to know before buying
- Customer feedback reports concerns about durability, including accounts of breakage within a year, and mixed views on build quality, battery life and vibration. Treat these as reported experiences, not a guaranteed outcome.
What’s in the box
Included- DiamondClean Smart 9400 sonic electric toothbrush
- 4 A3 Premium All-in-One brush heads
- USB charging travel case
- Charging glass
- Stand
Who is it for?
A good fit for
- Adults wanting app-linked brushing guidance and several brushing modes.
- Travellers who would use the included USB charging case.
- Users who value pressure feedback and reminders for brushing time and brush-head replacement.
Less suited to
- Buyers prioritising consistently positive reported durability or battery experiences.
- Anyone seeking a simpler toothbrush without app connectivity or multiple settings.
Customer reviews on Amazon
- 5 stars
64% 64% - 4 stars
14% 14% - 3 stars
5% 5% - 2 stars
3% 3% - 1 star
14% 14%
Customer feedback highlights effective cleaning and an appearance some buyers appreciate. It also reports mixed build-quality, battery-life and vibration experiences, alongside durability and cost concerns. The claimed two-week battery life depends on a specific standard-mode routine, so it does not settle those mixed battery reports. The toothbrush's app, pressure feedback and several modes may suit buyers seeking guidance, but reported durability concerns matter to anyone expecting long-term use.
Positive themes
- Customers describe the toothbrush as effective at cleaning teeth.
- Some customers appreciate its appearance.
Negative themes
- Feedback raises durability and value-for-money concerns, including reports of breakage within a year.
Mixed feedback
- Build quality is described both positively and negatively, with some feedback characterising it as flimsy.
- Battery life and vibration performance receive mixed feedback.
Frequently asked questions
How many brushing modes and intensity levels does it have?
The listing specifies four modes—Clean, White+, Gum Health and Deep Clean+—and three intensity levels.
How does the pressure sensor work?
The listing says a light ring on the handle flashes when too much pressure is applied, prompting the user to ease off.
What battery life is claimed?
Up to two weeks on one charge, based on two two-minute brushing sessions per day in standard mode.
What is listed in the package?
The stated set includes the toothbrush, four A3 Premium All-in-One brush heads, a USB charging travel case, and a charging glass and stand.
Alternative options
Philips Shaver i9000 Prestige Ultra, Wet & Dry Electric Shaver, Black, with Skin IQ Pro Technology, Triple Lift & Cut System, 360 Rotating NanoTech Precision Blades, 5 Shaving Modes, Model XP9405/31
£319.95
Philips Sonicare A3 Premium All-in-One, Genuine Replacement Toothbrush Heads, White, 6 Pack, HX9096/87
£44.99
Philips Sonicare C3 Premium Plaque Defence, Genuine Replacement Toothbrush Heads, White, 6 Pack, HX9046/87
£39.99
Philips Sonicare Next-Generation DiamondClean 9900 Prestige Sonic Electric Toothbrush with SenseIQ, Smart Coverage and Pressure Feedback, 24 Settings, Silver White, HX9813/91
£249.99
Philips Sonicare Next-Generation DiamondClean 8500 Sonic Electric Toothbrush − with Smart Pressure Feedback, and 18 Settings, Black, HX8514/12
£194.99
![Philips Sonicare 5300 Electric Toothbrush, Sonic Toothbrush with 2 Intensity Levels, Pressure Alert, EasyStart, SmarTimer and BrushPacer, Black, Model HX7101/01 [New Technology]](/i/MFCvk3fRBD7NFYJlFMKsecgqhvV3xvJNJNsvcL8xncyXT2aSJtgacbxwnaydBXE6GSzQNmQsGbOhyxShSP2jnuaf1zj5Wg0zl635fiUdXeqoivJvrOSTsNDWzJP_aGGYZwnvsx5JocU.jpg)
Philips Sonicare 5300 Electric Toothbrush, Sonic Toothbrush with 2 Intensity Levels, Pressure Alert, EasyStart, SmarTimer and BrushPacer, Black, Model HX7101/01 [New Technology]
£47.69
Philips Sonicare Next-Generation DiamondClean 8500 Sonic Electric Toothbrush − with Smart Pressure Feedback and 18 Settings, Powder White & Black, 2 Pack, HX8596/21
£269.99
![Philips Sonicare 5500 Electric Toothbrush, Sonic Toothbrush with 2 Modes, Pressure Alert, EasyStart, SmarTimer and BrushPacer, White, Model HX7110/02 [New Technology]](/i/w7aCMsV-CW_Bg5komwgowVrr8dekhsqc_5Pu8QV6I9AIXcMYZdEgxW9uFGDCRpy3kGX-bW5kghy1pKANE28CPQoJlZlg4WhwzaToPBJ-XojTkFNuJ9gYT-QhCl_J2CShMhfD_gzoGHc.jpg)
Philips Sonicare 5500 Electric Toothbrush, Sonic Toothbrush with 2 Modes, Pressure Alert, EasyStart, SmarTimer and BrushPacer, White, Model HX7110/02 [New Technology]
£74.98
SURI Pro Sonic Electric Toothbrush | Over 4+ Weeks Battery | Pressure Sensor | Aluminium Body | 2-Minute Timer | Plant-Based Head | Green
£89.00
Philips Sonicare BrilliantClean Limited Edition Electric Toothbrush - Smart Screen, Pressure Sensor, Brush Head Replacement, 2 Brushing Modes and SmarTimer, Black, Model HX3792/21 (Renewed)
£69.95
