Parents know bedtime is a perpetual battle, but a chart that has gone viral on Facebook might’ve made it just a little bit easier.
Originally shared as summer 2015 came to a close by first-grade teacher Stacy Karlsen of Kenosha, Wisconsin, the graphic shows what time a child should go to bed based on two factors: his or her age and desired wake-up time.
For example, if you have a 7-year-old who needs to be out the door by 8 a.m., then 8:15 p.m. is probably an appropriate time to hit the hay for a 7 a.m. wake-up.
The chart has been shared almost half a million times since it was first posted by Wilson Elementary three years ago. It has also received more than 10,000 comments and 63,000 reactions.
Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Parents newsletter.
“Mine is almost 11 … goes to bed 8h45 and wakes up 6h15 … almost right on!” wrote one mom.
“Boom, I got this bang on!!!” added another.
“It’s taken this school by storm — and more so, because barely 200 kids attend here and this chart suggesting what time your child should go to bed has been shared on Facebook more than 300,000 times,” Karlsen told local TV station Fox 6. “I found it coming across my personal page and I thought, ‘Wow, this is super helpful.’ “
RELATED VIDEO: How Fatherhood Changed Sexiest Man Alive Idris Elba
The chart starts at age 5 and continues through age 12. According to WebMD, children between 3 and 6 years old need 10 to 12 hours of sleep a day.
Children between the ages of 7 and 12 need 10 to 11 hours of sleep, while 12- to 18-year-olds need eight to nine hours, similar to adults.