This is a brief summary of sleep volumes for different ages in the first five years.

Birth to six weeks.
For many children, who are gaining weight well, sleep volumes will be 18 to 21 hours per day.

Six to 12 weeks.
The child now begins to "awaken" and have recognisable ‘happily awake times’.
Sleep volumes are large and may still be 17 to 21 hours per day.
By approximately three months a long night-time sleep, which includes one feed, and is approximately 12 hours long can be established.
Happily awake times are relatively short at 5 to 15 minutes.

Four to eight months.
This can be a period of stability.
The night sleep is approximately 12 hours long with or without a night feed.
The child may have established three day sleeps. These may total four or five or six hours of sleep.

Eight to ten months.
A period of transition.
Before eight months the majority of babies will have three day sleeps. By 10 months the majority will have stabilised on two. Transition may be period of some "untidiness". This means that some days there are three sleeps and others there are two. Few mothers report having trouble with this ambiguity.
A common question is which of the three day sleeps is lost first. Often it will be the third day sleep, sometimes referred to as a ‘pre dinner nap’.

Ten to 15 months.
This is often a period of some stability.
The child has a 12 hour night and two day sleeps.

15 to 18 months.
A period of transition.
The second day sleep is beginning to diminish. I tried to maintain both sleeps for as long as possible but there is great variability between children as to the age at which they cease the second sleep. The sleep which is often lost first is the one which occurs in the afternoon. The time of initiating the first day sleep is still managed by the happily awaken time concept.

18 months to 36 months.
This can be period of stability.
The night sleep is stable at approximately 12 hours.
The single day sleep is stable. The length of the day sleep varies considerably between children.

36 to 48 months.
A period of transition.
The day sleep may now be diminishing. There are days where the child needs that day sleep but it is not achieved. On these days the child may respond well to an early night.
By approximately age four the day sleep has been lost in the majority of children but in some children they may have a day sleep even up to school age.