OK to wake clock: what it is and when to start

By the Snoozaroo team · How we write our guides · Updated 12 November 2026

An OK to wake clock shows a young child the one thing an ordinary clock cannot tell them: whether it is still sleep time, or OK to get up. You will also see it written okay to wake clock, and called an OK to get up clock, a time to rise clock or, in the UK, a sleep trainer clock. They are all the same idea. This page explains how it works, the age it starts to make sense, and how to introduce one.

What an OK to wake clock does

A toddler cannot read the time, but they can read a picture. So the clock shows one thing through the night, such as a red light, a moon or a sky of stars, and a different thing from the wake time you set: a green light, a sun.

That is all it does. Without the clock, a child who wakes at half past five has no way of knowing it is not morning, and the only way to find out is to come and ask you. With it, the answer is in the room.

It does not make a child sleep. It makes the rule something they can see, and it takes you out of the argument: it is the clock that says not yet, not you.

Stay in bed: the pal asleep, with four of six stars still out.

The same clock, by other names

You may see it called	Where
OK to wake clock, okay to wake clock	The usual name in the United States and Canada, and used in the UK too
Sleep trainer clock, sleep training clock	The usual name in the UK, Ireland, Australia and New Zealand
OK to get up clock, time to rise clock, stay in bed clock	Plain descriptions of what it does
Red light green light clock, traffic light clock	The kind that changes colour
Toddler clock, children’s sleep clock	Shop and catalogue names

A sleep trainer clock has nothing to do with sleep training as a method for settling a baby. It is a clock for a child old enough to follow a simple rule.

What age does an OK to wake clock work from?

There is no official figure. Makers give different starting ages: Tommee Tippee lists its Groclock from 12 months, and LittleHippo says its Mella works best from about two, when children start learning colours (their own pages, read on 12 November 2026). We have not found an NHS page that gives an age. One that mentions these clocks, from NHS Greater Glasgow and Clyde, says: “Sleep Training Clocks can help children or young people to learn when it’s time to get up and when it’s time to go back to sleep.” Source: Sleep, Royal Hospital for Children, NHS Greater Glasgow and Clyde (https://rhc.nhsggc.org.uk/kids-for-families/healthy-lifestyle/sleep).

For Snoozaroo we say from about two and a half, with most children understanding it by three. The reason is what the clock asks of a child: to notice a signal, and then to wait. Most younger children can do the first and not the second. What matters more than the birthday is whether your child can follow a simple “when this, then that” rule in the day, and wait a short time when asked.

Before that the clock is still useful as a bedtime signal: the stars come out, so it is sleep time. The getting-up part comes later.

How to introduce one

Talk about it in the day. Show them what the clock looks like at night and in the morning, and say the rule in the words you will use every time: “Stars mean sleep time. When the sun comes up, you can get up.”
Set the wake time where they wake now. If they wake at half past five, set it for a quarter to six. The first few mornings should be easy to get right.
Move it slowly. Once they are waiting for the signal, move the wake time later by ten or fifteen minutes every few days.
Notice the wait. Praise staying in bed until the signal, not the waking. Some clocks help: with Snoozaroo’s Plus plan a present appears on the screen when the sun comes up, with a toy for their shelf.
Every grown-up, the same rule. If the answer at five is sometimes yes, the clock means nothing. If they come out early, walk them back quietly; what to do when a toddler won’t stay in bed has the steps.
Give it a week or two. Judge it after a fortnight, not after two mornings.

A light, a clock face or an app

Kind	How it shows the rule	How you set it
A light that changes colour	One colour for stay in bed, another for OK to get up	Buttons on the light, or the maker’s app
A clock face with pictures	Stars or a moon at night, a sun in the morning	Buttons on the clock
An app on a tablet or phone	A scene on the screen: in Snoozaroo, a pal asleep under six stars, then a sunrise	From your own phone

Each has its place. A light or a clock needs no tablet. An app costs nothing to try if you already have a tablet, and is set from your own phone. How to choose a sleep trainer clock compares them point by point, with the clocks UK parents ask about.

How Snoozaroo does it

Snoozaroo is an OK to wake clock as a free app for an Android tablet or phone, with iPad coming. At bedtime the child’s pal settles and six stars glow. The stars go out one by one through the night, so a child who wakes early can see how much night is left, not only that it is still night. When the sun comes up, the pal wakes and shows it is OK to get up.

You set bedtimes, wake-up times and naps from your own phone. See how the sleep clock app works.

OK to get up: the sun is up and the pal is awake.

Questions

Is an OK to wake clock the same as a sleep trainer clock?

Yes. They are two names for one thing: a clock that shows a young child when it is still sleep time and when it is OK to get up.

Is it OK to wake or okay to wake?

Both spellings are used, and shops use both. The clock is the same.

Do OK to wake clocks work?

They work as a signal, when every grown-up keeps to the rule. A clock does not change when a child wakes. It changes what they can know when they do: that it is not morning yet. Nobody can promise more than that, and we do not.

My toddler gets up before the clock says so. What now?

Walk them back quietly and point to the clock, the same way every time. Then look at the wake time: if it is much later than they usually wake, bring it closer and move it later in small steps. A wait that is too long to manage teaches them to ignore the clock.

What time should I set it for?

Start at, or just after, the time your child wakes now. Move it later in small steps once they are waiting for it.

Is there an OK to wake clock app?

Yes. Snoozaroo is one, for Android tablets and phones, free to start, so you may also see it called an OK to wake app or a sleep trainer app. An iPad version is coming.

Does it work for naps?

Yes. The same signal works in the day. See a nap clock and quiet time clock.