Most electric toothbrushes use lithium-ion batteries, but some still use nickel-metal hydride
The short answer is: most do, but not all. Lithium-ion batteries are now the standard in electric toothbrushes because they hold a charge longer, last more charge cycles, and weigh less than older battery types. However, some budget models and older toothbrushes still use nickel-metal hydride (NiMH) batteries, which are cheaper to manufacture but drain faster and need replacing sooner.
If you bought your toothbrush in the last five years from a major brand — Oral-B, Sonicare, Colgate, Waterpik — it almost certainly has a lithium-ion battery. The exceptions are usually the lowest-priced models under $30 or specialty toothbrushes designed for travel. Check your manual or the product page to be certain, since manufacturers list the battery type in the specifications.
Key Takeaways
- Lithium-ion batteries are standard in most modern electric toothbrushes and last longer per charge than older nickel-metal hydride batteries.
- A lithium-ion toothbrush typically holds a charge for two to three weeks of daily use, while NiMH models need charging every few days.
- Lithium-ion batteries degrade over time and usually need replacement after three to five years, depending on how often you charge.
- You can find the battery type in your toothbrush manual, on the product page, or by contacting the manufacturer directly.
Why lithium-ion became the standard
Lithium-ion batteries won out over nickel-metal hydride for three practical reasons: energy density, cycle life, and weight. A lithium-ion cell stores more energy in the same physical space, so toothbrush makers could either make the handle lighter or extend the time between charges. Most chose to extend the charge time.
A typical lithium-ion toothbrush runs for two to three weeks on a single charge with twice-daily brushing. A nickel-metal hydride toothbrush of the same size needs charging every three to five days. For a tool you use twice a day, that difference matters. Lithium-ion batteries also survive more charge cycles — usually 500 to 1,000 full cycles before capacity drops noticeably — compared to 300 to 500 for NiMH.
The trade-off is cost. Lithium-ion cells are more expensive to produce, which is why the cheapest toothbrushes still use NiMH. But the price gap has narrowed enough that even mid-range models now come with lithium-ion as standard.
How long a lithium-ion toothbrush battery lasts
The battery itself lasts the life of the toothbrush if you use it normally — typically three to five years before you notice the charge time dropping. After that, the battery holds less energy with each charge cycle. A toothbrush that once ran for three weeks might run for two weeks, then one week, as the battery ages.
What shortens battery life is overcharging. Leaving your toothbrush on the charger constantly, or charging it every single day when it still has 50 percent battery, stresses the lithium-ion cells. The best practice is to let the battery run down to near-empty once a month, then charge it fully. Most toothbrush chargers are designed to stop charging once the battery is full, so leaving it plugged in overnight is usually safe — but unplugging it when full extends the battery's useful life.
Heat also degrades lithium-ion batteries faster. Storing your toothbrush in a hot bathroom or leaving it in direct sunlight shortens its lifespan. A cool, dry cabinet is better.
Replacing a lithium-ion battery in your toothbrush
Most electric toothbrushes are not designed to have the battery replaced by the user. The battery is soldered or glued inside the handle, and opening it risks damaging the motor or waterproofing. Some models — particularly higher-end Oral-B and Sonicare toothbrushes — can be opened by a dentist or repair shop, but the cost of replacement usually runs $40 to $80, which is close to the price of a new toothbrush.
A few specialty toothbrushes, mainly travel or budget models, have user-replaceable batteries. These are rare and usually noted in the manual. If your toothbrush has one, the battery type and part number will be listed in the documentation.
When the battery no longer holds a charge, your options are to replace the toothbrush or contact the manufacturer to ask about repair options. Some brands offer mail-in replacement programs for a flat fee, though this is less common than it once was.
How to check what battery your toothbrush has
The easiest way is to look at the product manual or the manufacturer's website. Search for your toothbrush model number — it is usually printed on the handle or the charger — and look for the specifications section. The battery type and capacity (measured in milliamp-hours, or mAh) will be listed there.
If you no longer have the manual, check the toothbrush itself. Some models print "Li-ion" or "Lithium-ion" on the handle. Others print only the voltage and capacity. A voltage of 3.7V or higher usually indicates lithium-ion; 1.2V usually indicates NiMH.
You can also contact the manufacturer's customer service with your model number. They will tell you the battery type and, if needed, how to replace it or where to send the toothbrush for repair.
Lithium-ion versus other battery types in toothbrushes
Three battery types appear in electric toothbrushes: lithium-ion, nickel-metal hydride, and nickel-cadmium (now rare). Lithium-ion is lightest and lasts longest per charge. Nickel-metal hydride is heavier and drains faster but is cheaper and safer if the battery is damaged. Nickel-cadmium is almost extinct in consumer toothbrushes because it contains toxic cadmium and has poor cycle life.
Some very old toothbrushes or budget models sold in discount stores may still use NiMH. If you are buying a new toothbrush and want the longest time between charges, look for "lithium-ion" or "Li-ion" in the product description. Most toothbrushes under $50 now use lithium-ion, and nearly all models over $50 do.
What happens when a lithium-ion toothbrush battery fails
A failing lithium-ion battery in a toothbrush shows itself in a few ways: the toothbrush no longer holds a charge, it dies mid-brushing, or it takes much longer to charge than it used to. Sometimes the toothbrush will not turn on at all, even after charging overnight.
If this happens, the battery has reached the end of its useful life. The motor itself is usually fine — the battery is the part that wears out. At this point, you can replace the toothbrush, contact the manufacturer about repair, or take it to a dentist's office to ask if they can replace the battery. Do not try to open the toothbrush yourself unless the manual explicitly says it is user-serviceable, because you risk breaking the waterproofing or damaging the motor.
Frequently Asked Questions
Can I use my electric toothbrush while it is charging?
No. Electric toothbrushes are waterproof when sealed, but the charging contacts are not designed to handle water while power is flowing. Using the toothbrush while it charges risks electrical damage or injury. Always unplug it before use.
Is it bad to leave my toothbrush on the charger all the time?
Most modern toothbrush chargers stop supplying power once the battery is full, so leaving it plugged in is safe. However, the battery ages slightly faster if it stays at 100 percent charge constantly. Unplugging it when full extends the battery's lifespan by a few months.
Why does my toothbrush battery drain so fast now?
Lithium-ion batteries lose capacity over time — usually after two to three years of daily use. If your toothbrush is older than that and no longer runs for more than a few days, the battery has degraded and needs replacement. Heat exposure and constant overcharging speed up this process.
Can I replace the battery myself?
Most electric toothbrushes are sealed and not designed for user battery replacement. Opening one risks damaging the motor or waterproofing. Check your manual to see if your model is user-serviceable. If not, contact the manufacturer or a repair shop for options.
What should I do with an old electric toothbrush with a dead battery?
Do not throw it in the trash. Lithium-ion batteries are recyclable and some contain materials that are harmful to landfills. Take it to an electronics recycling center, a dentist's office (many collect old toothbrushes), or check your manufacturer's website for a mail-back program.