Whether the baby monitor is audio-only, combines video and audio functions, or is app-based. "App used with main unit" means your smartphone or tablet uses an app and Wi-Fi/3G/4G to connect directly to the monitoring device. Some apps cannot be used on their own and require a camera, so we've listed the price of that rather than the price of the app.

A baby monitor needs to score well for both ease of use, sound performance and picture quality (if available) to be a Recommended product. We recommend models scoring 85% and above.

For audio/video products, this is made up of picture performance (30%), sound performance (40%) and ease of use (30%). For audio-only products, the overall score is made up of sound performance (70%) and ease of use (30%).

We test how well the baby unit can pick up soft sounds, how well the carer unit can reproduce that sound, signal range and performance through walls. Results may vary depending on your home Wi-Fi coverage. For app-based products, we define the carer unit as the tablet/phone.

We look at ease of using the controls on both the baby and carer unit, labelling, ease of setup including handling, positioning and adjusting settings, and ease of accessing the batteries and connecting the adaptors. For apps we class the tablet/phone as the carer unit.

In 2016 we began to include picture performance in the overall score for baby monitors, if that monitor has video. The picture performance score consists of picture range (50%), picture sensitivity/picture quality (25%) and picture immunity from interference (25%).

Quality of the baby monitor picture in daylight conditions.

Quality of the baby monitor picture in dim lighting conditions.

Quality of the baby monitor picture in dark lighting conditions. Many video-enabled baby monitors have an infrared feature that allows you to see your baby in the dark, albeit at high contrast and in black and white. Monitors that don't have this feature (such as ones which use your phone/tablet) will score zero for visibility.

How well the baby unit and carer unit can maintain acceptable sound monitoring at various distances with obstacles (walls) separating them.

How well the baby unit can pick up soft sound and how well the carer unit can reproduce the sound (and produce visual indication if applicable).

How much interference the baby monitor could cause to a common household appliance, and how much the baby monitor could be affected by interference from a common household appliance.

This row shows which products are still available in shops ('Tested model') and which models have been discontinued. You might still be able to find discontinued models in second-hand stores or online.

This is the typical recommended retail price at the time of testing but you might be able to shop around for a better deal.

Some apps and cameras connect to a phone/tablet as the carer device, so the weight will depend on the device you're using.

Some apps and cameras connect to a phone/tablet as the carer device, so the dimensions will depend on the device you're using.

A motion monitor detects movement and sends a notification if your baby is restless. It can also detect lack of movement after a certain amount of time (specified in the manual) and send an alert.

The sound indicators will light up to alert you when your bub cries. They allow you to 'see' the noise your baby makes rather than hear it.

Some baby monitors sound an alarm if the temperature is outside a certain range. Regardless of the temperature, it's still important to follow safe sleeping guidelines such as putting your baby to bed on their back, with their face uncovered and minimal bedding.

This lets you easily carry the unit around the house while you're busy doing other chores.

This lets you play a lullaby or soothing noise in the baby's room.

This feature lets you talk to your baby from the carer unit.

Does the baby monitor have a low battery indicator.

Does the carer unit or smartphone app have a low battery indicator.