This is an incredibly common question.
There is no hard and fast rule with awake times. Take two babies of the same age - I can guarantee their ideal amount of awake time will not be the same. However, knowing a range of age appropriate awake time for your baby's age can help you identify when they might be ready for a sleep.
Here is your guide to awake times for babies from birth to 12 months of age. Always use your baby/child's tired signs in conjunction with the awake time guide to prevent them going to bed overtired or undertired.