Exactly how much sleep your kids should be getting.

Good news, parents – we’ve found a genius tool to make your kids’ bedtime routine that little bit calmer.

Introducing the Sleep Calculator for Kids – a website that helps you work out the perfect time for your child to go to sleep and exactly how much sleep they should be getting.

You can thank us later.

You just visit the website, enter your child’s age and the time they need to wake up in the morning, and voila, it will give you a list of optimal times based on counting sleep cycles.

According to the website, every child has a unique body clock, which means some may need 12-plus hours of shut eye each night, while others need far less.

“Happy mornings rely on sleeping patterns that fall in line with sleep cycles. And that’s where our sleep calculator helps,” the website states.

“The Sleep Calculator for Kids works out the best time for your child to wake up by counting sleep cycles. Each cycle for a 4-year-old lasts around 30 minutes.

“Waking up mid-cycle can mean your child wakes up grumpy. So your results show wake-up times that are between cycles – that’s when you’re most likely to be greeted with a smile from your child. Most children take roughly 14 minutes to nod off (depending on the quality of the bedtime story). This time is included in your results.”

That’s it – we’re sold.

What bedtime routine do you stick to?