The Best Bath Thermometers, Tested by a Mom of One

​​The AAP suggests using your elbow or wrist to test the water temperature before putting your baby in the tub. But if you’re like me and want to know the exact water temperature your baby likes, the Famidoc Baby Bath Thermometer is the best in show.

I dropped the Famidoc Baby Bath Thermometer into the tub over and over and always got accurate readings—just a degree or two off from the control. This product also functions as a room thermometer and when testing the air temperature, it was just as accurate. You’d think all baby bath thermometers would be equally reliable, but unfortunately that’s not the case. In fact, I was stunned to discover that another thermometer I tested was off by as much as seven degrees. That’s a big problem when you’re expecting a cozy 100°F bath for your baby but end up with a dangerous 107°F bath water instead.

Aside from providing an accurate temperature, this sweet manta ray-themed thermometer takes a reading every five seconds, so I always knew if the water was just right. The LCD screen on its back clearly displays the temperature along with “cool” or “hot” warnings if the water isn’t ideal. I conducted a range of water temperature tests and the hot water alert was triggered when the water reached 102°F, while the cold water alert appeared when the temperature dipped to 90°F. I especially loved the color-coded light—it turns blue when the water is chilly and red when it’s too hot, so I could easily check for an alert from the side of the tub while my little one splashed about. My only small gripe was that, since it lies flat, the room temperature was difficult to read unless I was standing above it looking down.

The fun shape was easy for my daughter’s little hands to grab, plus there are no buttons to accidentally press—just give the manta ray a shake to turn it on. It’s safe to fully submerge and automatically shuts off after 30 minutes, which is great for my family because we don’t always have time to clean up from bathtime before starting our bedtime routine.

Type: Digital | Display: LCD | Power on: Shake | Automatic shut-off: Yes, 30 minutes | Batteries required: Yes

The Nuby Penguin Bath & Room Thermometer can monitor both bath and room temperatures (though not simultaneously). This dual function is important because even if your bath water starts at the perfect temperature, a cool room can quickly cause the water to drop by a few degrees, explains Robert Quillin, MD, board-certified pediatrician and medical director at Pediatrix Medical Group. He says the ideal room temperature for bathtime is around 76 to 78°F.

In testing, thermometers with a sturdy base allowing them to stand upright or sit at an angle were much easier to see from across the room than those that lie flat. That’s what makes this little penguin so practical—it floats on its back in the tub with the temperature reading facing upward, but can also stand on its two feet, with the display screen facing outward, when measuring the air temperature. It was convenient to glance over and see the temperature while readying my baby for bathtime.

The Nuby thermometer had a particularly great display in the bathtub, too. Its numbers and words were the largest of all the models I tested. When the temperature reaches 102°F or higher, it lights up red and the words “HOT” flashed across the screen—much easier to spot than the tiny print of other thermometer displays. Thanks to the large display screen, the temperature is easy to read from the side of the tub or when the thermometer is sitting on a surface in a room. And I also appreciated the fact that it provides "real-time" temperature readings with no delays. There’s no obvious cold-water alert, but that makes sense since it also doubles as a room thermometer. Other models we tested flash blue when the temperature drops below 90°F—even when it’s out of the water. And, if you forget the recommended room (nursery) and water temperature for babies, they’re conveniently printed right there on the Nuby thermometer.

Type: Digital | Display: LCD | Power on: Tap | Automatic shut-off: Yes, 30 minutes | Batteries required: Yes

Looking for a thermometer that doubles as a bath toy? Dr. Brown’s CleanUp Temposaurus Floating Bath Thermometer features a sealed battery compartment, a fun suction cup feature, and a child-friendly dinosaur design with chunky limbs that are easy for little ones, like my daughter, to grab.

This thermometer floats well and consistently stays right side up, yet another reason why it is the best option for play. It’s made from BPA-free materials, which is great because my daughter loved chomping on its arms and legs. I also love the suction cup backing—I stick it to the tub wall when it’s not in use and was able to hang items like a washcloth off its arms. Plus. my little one got a real kick out of grabbing the cute dino when it was suctioned onto a mirror at home.

Safety is of the utmost importance if you plan to let your little one play with a baby bath thermometer (always under supervision, of course). It’s important to note that many models use button batteries to power their displays and, if swallowed, these batteries can cause life-threatening internal burns. While most baby bath thermometers have baby-proof, water-resistant battery compartments, Dr. Brown’s model takes battery safety a step further: its battery is fully encased, making it inaccessible to both you and baby. However, there’s a downside to this—a significant one, in my opinion: the batteries aren’t replaceable or rechargeable. Once they die, the thermometer stops working. According to other parents, the battery life ranges from a few months to as little as two months. To help conserve battery life, there is an on/off power button. I like that I can’t accidentally turn it on with a shake (also great for travel!), but it could be a bit of a headache if you have a tot who likes to press buttons. That said, the button was too tough for my daughter's tiny fingers to press. It also has a 10-minute automatic shut-off feature, which is nice for saving battery, but a little inconvenient if bathtime runs longer.

Overall, the accuracy is fairly good, although it consistently reads about two degrees below the control thermometer. Two features I liked were the real-time updates and the color-coded temperature alerts. The digital display updates every 15 seconds, so you can monitor the bath water temperature as it cools. And the screen displays the temperature using large numbers that can be easily read from the side of the tub. Meanwhile, the LED light on the display screen flashes red when the water is too hot, turns green when the temperature is at a safe level and then flashes yellow if it dips to 90°F or under. While it’s fair to say this thermometer has a limited lifespan, it was still my favorite option for play thanks to the safety features and cute dinosaur design.

Type: Digital | Display: LCD | Power on: ON/OFF button | Automatic shut-off: Yes, 10 minutes | Batteries required: Yes

The Doli Yearning Digital Baby Bath LCD Thermometer is full of handy features to make bath time as seamless as possible. It’s the only thermometer I tested that lets you switch between Celsius and Fahrenheit with the press of a button. My favorite feature, though, is the ability to adjust the hot water alarm ("HOT" display and flashing red LED light) to fit your family’s preferences.

By default, the hot water alarm is set to 102.2°F, but my baby likes her baths a little warmer (and I noticed this thermometer runs about 2 degrees cooler than my control). So, I set the alarm to 104°F, which is as high as it’ll let you go due to a built-in safety feature. Adjusting it took just a few seconds: I held down “set” and used the plus button on the back to bump it up. If your baby likes the water a little cooler, you can adjust the alarm in the opposite direction. The cold water alarm is set at 86°F (with a “COOL” display and blue LED light) and can’t be changed.

The thermometer is fast—it gives results in as little as three seconds—and it automatically turns off after 30 minutes. Unfortunately, like so many other baby bath thermometers, the Doli Yearning relies on sight alone. An audible warning for high temperatures would provide an extra layer of accessibility that many parents would appreciate.

Finally, in terms of play value, this thermometer performed well. My four-month-old loved grabbing and feeling the thermometer—it’s a nice texture, and she’s all about tactile exploration at this age. It’s a little tricky for her to grasp right now, but I can see it becoming a fun toy as she gets older. I also like that it has a friendly face, but it’s more on the realistic side rather than too cutesy.

Type: Digital | Display: LCD | Power on: ON/OFF button | Automatic shut-off: Yes, 30 minutes | Batteries required: Yes