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Updated: 16 Feb 2022

How we test electric toothbrushes

Discover the lengths we go to testing electric toothbrushes to unearth the Best Buys that help keep your teeth and gums clean and healthy.
Patrick Gallagher

The best electric toothbrushes sweep away plaque to help keep your teeth sparkling and your gums clean and healthy.

To find the models with the best cleaning power, we thoroughly test electric toothbrushes by measuring how much plaque each brush can remove.

We’ve tested and rated electric toothbrushes from the biggest brands, including Oral B, Philips Sonicare and Colgate – and found that you don’t need to fork out for gleaming results.

Our reviews answer the important electric toothbrush questions, including:

  • Will this electric toothbrush leave my teeth clean?
  • How often will I need to recharge this electric toothbrush?
  • Will it recharge quickly?
  • How easy to use is this electric toothbrush?
  • Should I buy it?

Head straight to our electric toothbrush reviews to find the perfect model for you.

Or read on below to find out more about the details of how we test.

Will this electric toothbrush leave my teeth clean?

The key to keeping your teeth and gums clean and healthy is to prevent plaque from building up. So to see how good an electric toothbrush is at removing plaque, we enlist a panel of 21 triallists to clean with each brush – and we measure the results.

When a triallist arrives at our lab, our dental expert measures the amount of plaque on the inside and outside surfaces of each and every tooth. The triallist brushes their teeth for two minutes – the amount of time dentists recommend we brush our teeth for – and we then measure how much plaque has been left behind. This is repeated over several weeks until each triallist has brushed with each brush – a total of 200 teeth-cleans overall.

Once we have all 2,276 before and after plaque readings, we crunch the numbers to see which brushes are best at removing plaque, and which don’t clean as well. 

To see which ones come top in our tests, head straight to our picks of the best electric toothbrushes

Not a Which? member? Join Which? to access all our thousands of independent reviews and Best Buys. 

How often will I need to recharge this electric toothbrush?

A great electric toothbrush will last for a long time between full charges.

To see how long the battery lasts, we see how many two-minute brushes a fully charged battery gives. We test in the way you use toothbrushes, so we leave a 12-hour gap between each run, just like you would when you’re brushing twice a day. We also add a weight to the head of each brush to mimic the effect that the pressure you use when brushing has on the battery.

We’ve found some electric toothbrushes that keep going for weeks, while others need recharging on a weekly basis.

Will the electric toothbrush recharge quickly?

The best electric toothbrushes power up quickly, so you can place them on their charger in the morning and they’ll be fully charged by the time you come to use them again in the evening.

Our tests have uncovered big differences in charging times between models. We found some that recharge in less than three hours, while others take over 18 hours.

Will the electric toothbrush be quiet and feel nice to brush with?

Changing from a regular toothbrush to an electric model and switching between different types of electric toothbrush can take some getting used to. To help you find the brushes that feel best, our panel of triallists rate how comfortable each model is to brush with.

They also rate how noisy they are during use, to help you pick a quieter brush if you clean your teeth while other members of the household are sleeping.

Should I buy it?

Each of the above assessments go towards making up a total test score, which is the overall percentage figure awarded to each electric toothbrush.

Certain tests are more important than others in determining just how good each electric toothbrush is, and so carry different weights. For instance, we think that cleaning efficiency is more important than how much noise each brush makes.

The total test score is made up of the following:

  • 70% Cleaning efficiency
  • 15% Battery life and recharge time
  • 10% Ease of use
  • 5% Noise

An electric toothbrush has to achieve a total test score of at least 79% to be awarded our Best Buy recommendation. A toothbrush that only manages a score of 45% or less will be marked as a Don't Buy.