Why age is the wrong question

The HSE gives a range rather than a target: children "will usually be ready to learn between the age of one-and-a-half and 3 years old. But each child is different and will start in their own time." The American Academy of Pediatrics is blunter still, saying training "can begin as soon as parents and children want to start", that the average age in the United States is between 2 and 3, and that most children are trained by 4.

The AAP describes toilet training as three separate things arriving at once: knowing what the body is doing, having the physical skills, and being willing. Children show signs of bladder and bowel control between 18 and 24 months, but control is only the first of the three. That is why two children the same age can be months apart, and why "she's two, she should be out of nappies" is not a clinical statement.

The readiness signs, as national bodies actually list them

The HSE's list is the most complete published. Your child is likely ready when they:

can stay dry for 2 hours
ask to be changed
ask to use the potty
have regular poos
ask to wear underwear
follow simple instructions, for example, "do you need to go?"
can let you know when they need to go
can pull their pants up and down
are physically able to sit on a potty themselves and stand up when they've finished

The AAP's list overlaps and adds two useful observations: the child "is dry at least 2 hours at a time during the day or is dry after naps", and shows recognisable signs of needing to go — "grunting, freezing, squatting". It also counts disliking a wet nappy and asking for "big-kid" underwear as readiness signals, because both indicate the child has noticed what is happening.

You do not need every item on either list. You do need several, and in particular you need the physical ones, because a child who cannot get their own trousers down is being set up to fail.

Getting ready before you start

The HSE recommends a run-up rather than a cold start. Change nappies in the bathroom so the child links nappy changes with the toilet, and encourage handwashing afterwards. Talk about it — "tell your child that when they are a big girl or boy they will be able to go to the toilet to do their pee and poo" — and read picture books about it together. Get them involved by changing them standing up and letting them help with their clothing. The AAP adds the simplest one: let children see you use the toilet and wash your hands afterwards.

How to actually do it

The HSE's practical guidance is specific enough to follow.

Clear the diary. "Set aside 3 to 4 days when you are at home to begin toilet training. Try to keep the same routine in the weeks that follow."
Tell the nursery or childminder that you are starting, so the approach matches in both places.
Use the reflex. Sit your child on the potty "first thing after meals and naps, and before bedtime", because "we all have a natural reflex to go to the toilet after eating."
Have a potty on every floor if your home is on two levels.
Watch for the signals. "They might hop up and down, hold their pants or hide. Get them to the potty quickly."
Dress for it. Easy-to-care-for clothes that a toddler can pull up and down.
Boys sit first. The HSE recommends training boys sitting down initially, since "he may want to poo as well as pee", with standing up coming later if he wants.
Pull-ups are a step, not a substitute. "They should be a step towards underpants, rather than a replacement for nappies."

Timing matters more than technique. The HSE says plainly: "it is not a good idea to start toilet training if you are about to move home or have a new baby."

What not to do

This is where the published guidance is unusually firm, and where a lot of popular advice goes wrong.

Do not force it. The HSE: "do not force your child to toilet train if they are unhappy or do not want to train. Stop and try again in 2 to 3 weeks."
Do not make them sit until something happens. "Children cannot make themselves pee like adults can. You can only train your child to 'hold on' once they get the urge to go." Nor should a child be made to hold on to a poo — the HSE notes they may not be able to, and it is uncomfortable.
Do not shame. The HSE's wording is worth quoting exactly: "try not to get upset or impatient with your child while they are learning. Do not use language that shames."
Do not turn it into a contest. The AAP: "remember that children control when and where they pee and poop. So power struggles, begging, pleading, rewarding, and punishing keep children from managing their own toileting."

The two bodies differ mildly on rewards. The HSE supports reward charts, with one strict rule: "do not remove a star from the chart if your child is naughty or has an accident. They earned the reward. Taking it away can discourage them." The AAP leans the other way, preferring specific praise and advising you "avoid treats and punishments". Both agree that praise costs nothing and that, as the HSE puts it, "there is nothing more important to your child than your love and cuddles."

Nights are a separate project

Daytime dryness and night-time dryness are not the same skill and do not arrive together. The HSE advises waiting until "you notice your child waking up dry for 3 to 4 weeks" before trying night-time training, and then protecting the mattress and telling your child plainly that it does not matter if they wet the bed.

Two pieces of HSE advice contradict common practice. First, on drinks: "there is no benefit in stopping your child drinking after 6pm. It's bad for your child's bladder and can dehydrate them." Children should have six to seven good-sized drinks spread through the day. Second, on lifting: "lifting a child out of bed to go to the toilet late at night is not a great idea. They are sleepy and this doesn't help them develop control." NICE says the same in its bedwetting guideline — "neither waking nor lifting children and young people with bedwetting, at regular times or randomly, will promote long-term dryness."

For expectations, the numbers are reassuring. The HSE says "most children are not dry every night before their 5th birthday" and that 15% of five-year-olds wet the bed from time to time. NICE puts it at approximately one in five children of four and a half wetting the bed at least once a week.

When to ask for help

Speak to your health visitor, public health nurse or GP if your child has been dry for a while and starts wetting again. The HSE names the two things worth excluding: "it may mean they have a bladder infection or constipation." NICE goes further for younger children, advising that under-5s who wet the bed are assessed for constipation, "as undiagnosed chronic constipation is a common cause of wetting and soiling in younger children."

Also worth a conversation: a child over two who understands what they need to do and is trying, but is still wetting during the day as well as at night. NICE recommends considering further assessment in exactly that situation. And if training simply is not happening after several genuine attempts, that is a normal thing to raise at a routine review rather than a failure to confess.

Potty Training: Signs of Readiness