The timing of toilet training: What's the best potty training age?

© 2006-2015 Gwen Dewar, all rights reserved

What is the right potty training age? The answer depends on you, your goals, and the characteristics of your child. Here I cover

  • What the scientific evidence says about the timing of potty training
  • Infant potty training (0-12 months)
  • Older infant/ young toddler training (12-18 months)
  • Older toddlers (18-24 months)
  • Potty training after 24 months


In many parts of the world, toilet training begins early--sometimes within weeks of birth. Without being punished or abused, babies learn basic toilet training skills before they can walk. And they never wear diapers.

The situation is very different in the United States, where children may wear diapers for 2, 3 or even 4 years. According to a recent study, African-American parents believe that toilet training should begin around 18 months. Caucasian-American parents believe that training should start even later--after 25 months, on average (Horn et al 2006).

These attitudes are new. In past generations, most American children were out of diapers by 18 months (Martin et al 1984). Today, many kids don’t master basic toilet training skills until they are almost 3 years old. In a recent study, more than half the children over 32 months failed to stay dry during the day (Schum et al 2002). It’s a trend observed in Europe, too (Largo et al 1996; Bakker and Wyndaele 2000; Horstmanshoff et al 2003). Since the Second World War, kids are taking longer and longer to learn toileting skills.

Should you follow—or buck—this trend?

Potty-trained children avoid diaper rash and diaper-related infections—like yeast, giardia and rotavirus. Their parents save money and time on diapering, and have more flexibility when searching for preschools.

This suggests that an earlier potty training age is better. But many parents worry that early training can be harmful. They’ve heard potty “experts” warn that early training causes behavioral problems or personality disorders. It’s therefore surprising to discover that these worries are misplaced.

The timing of potty training: What the scientific evidence says

Despite what you might have heard about behavioral problems or Freudian personality disorders, there is no scientific evidence that an early potty training age harms children.

In fact, earlier training may be beneficial.

Besides avoiding diaper rash and diaper-born infections, young children who were trained in infancy are less likely to suffer recurrent urinary tract infections. That's likely because they learn to empty their bladders completely -- eliminating any residual urine that can harbor bacteria. Children who don't begin training until after the age of 24 months may not reach this milestone until their third birthdays (Duong et al 2013).   There is also evidence that early trainees are at lower risk for developing problems with incontinence later in life. For the details, read my article on what scientific studies tell us about the timing of potty training.

Why does early training have a bad rap? One reason, I suspect, is that people confuse “when to train” with “how to train.” Many people assume that early training means using harsh, coercive methods. It does not. When parents use gentle, age-appropriate methods, early training is safe.

Nevertheless, early training isn’t right for everyone. In the rest of this article, I compare the advantages and disadvantages associated with training four different potty training age groups:

  • Infants (0-12 months)
  • Young toddlers (12-18 months)
  • Older toddlers (18 months and up)
  • Preschoolers (27 months and beyond)

Infant potty training: 0-12 months

It sounds bizarre to many Westerners. But for parents in places like India, China, and East Africa (deVries and deVries 1977; Boucke 2002), the traditional potty training age is early infancy. In these societies, parents learn to recognize their babies’ body signals and to use these signals to anticipate when their babies eliminate.

When the infant is ready to go, the parent holds him over a sink, bowl, toilet, or the open ground. As the infant voids, the parent makes a characteristic sound or gesture. The baby learns to associate this parental sign with voiding, and, eventually, the parental sign becomes an invitation to void. When the baby feels the urge to go, he learns to hold back for a brief time until his parent gives him the “all clear.”

This isn’t what many people mean by “toilet training.” Babies obviously can’t walk or flush or wipe themselves, so infant toilet training is necessarily a more modest affair-- staying dry with parental supervision.

But such early training has its benefits. To the degree that babies avoid diapers, they avoid diaper rash and diaper-associated infections.

Parents also avoid some of the problems associated with training older children. Babies aren’t used to wearing diapers, so they don’t have as many habits to break. And at this early potty training age, the smell of a child’s urine and feces is less objectionable to most people. If you wait until a later potty training age, cleaning up accidents will be more unpleasant.

When exactly does training start?

Traditionally, infant potty training begins during the first three months after birth (Boucke 2003). However, some advocates recommend a somewhat later potty training age (3-6 months), when babies pee less frequently and can sit up on their own. Once a baby can sit up--straight and steady--you can train her on a potty chair.

Learn more about a chair-based training method here.

It’s possible to start later, too--between 6-12 months.

However, toilet training veterans say infant training can be more difficult if your baby has learned to crawl or is learning to walk. Once babies discover mobility, they are less patient about sitting still on a potty chair. And one writer suggests that older babies, like older children, have become accustomed to wearing diapers and ignoring their body signals (Boucke 2003).

Choosing the right potty training age for older infants and young toddlers (12-18 months)

In 1920s and 1930s, European and American parents often began training between 12-18 months (Bakker and Wyndaele 2000).

However, depending on your child’s personality and developmental schedule, this could be a difficult potty training age.

For one thing, older babies and toddlers may find it hard to break the diaper habit. For another, children learning to walk may be too excited to sit still on a potty chair (Brazelton and Sparrow 2004).

In one study, children aged 15-19 months were more resistant to sitting on potty chairs than were younger and older children (Sears et al 1957).

But this potty training age has its advantages. Children under 18 months are often eager to please adults--a trait that older kids may lack (think of the “terrible twos.”)

If you’re interested, you can try the infant potty-chair method. If your child resists, back off and try later. And keep realistic goals. This potty training age is about staying dry with careful parental supervision.

If you decide to wait until a later potty training age, you can still put this time to good use. The interval between 12-18 months is the perfect time to start thinking about toilet readiness--a set of skills and interests that will help your child master advanced toilet skills later on (see below). You can make potty training easier if you actively prepare your child months in advance. Find tips on potty training preparation here.

Potty training after 18 months: Should you wait for signs of "toilet readiness?"

According to many potty training guides (American Academy of Pediatrics 1999), most children are not ready to begin training until 18-24 months.

However, there is nothing sacred about this potty training age-range. The recommendation that you start after 18 months is based on the idea that children should show signs of “toilet readiness” before you ask them to use the potty. A variety of diagnostic signs have been proposed. Many of these signs require pretty advanced developmental skills--hence their association with an older potty training age.

Proposed signs include developmental milestones--like walking, the ability to follow verbal commands, and the ability to stay dry for two hours at a time. They also include new attitudes, like “your child says he wants to do things for himself,” and “your child tells you he wants to wear grow-up underwear.”

Waiting until your child is ready sounds reasonable. Who would want to train a child who isn’t ready? The trouble lies with definitions of readiness.

Does your child need to walk to use a potty? Does your child need to express an interest in underwear? The answer depends on your goal.

If your goal is for your child to walk into the bathroom and sit on the potty by herself, then you obviously should wait until she can walk. But if you’re interested in the more modest goals of infant-toddler training, you don’t need to wait for signs of advanced “readiness.”

But even if your goal is complete toilet independence, you must work up to this goal gradually (Bakker 2002). No matter when or how you train, your child will be less competent than an adult. Most fully-trained children aren’t ready to go to the bathroom unattended until 36 months or later (Gesell and Ilg 1943; McKeith 1973; Bakker 2002).

Meanwhile, it’s probably not good idea to wait passively for your child to exhibit the signs.

For one thing, it can lead to late training--a problem if you prefer an earlier potty training age.

One recent study (tracking over 265 kids of potty training age for 12 months or more) found that children did not show many signs until after their second year (Schum et al 2002).

For instance, most children did not show an interest in using the potty until after 24 months. “Staying dry for over 2 hours” took more than 26 months for half the children, and most kids couldn’t pull down their own underwear until they were over 29 months old (Schum et al 2002).

More importantly, passive waiting does nothing to help your child get ready. If you review the official checklists, you’ll see that many--if not most--signs can be encouraged or taught.

Regardless of your long-term goals, it makes sense to prepare your child for training (Canadian Pediatric Society 2000; Schmidt 2004; Sears et al 2002). With the right kind of preparation, you may help your child reach potty training age earlier.

Potty training after 24 months: Is it better to wait?

For many American children today, “potty training age” means 24 months or beyond. Is this a good thing?

Unfortunately, there hasn’t been much research on this subject.

One study reported that an earlier potty training age--starting between 18-24 months--was associated with longer total training times overall (Schum et al 2002).

Other research suggests that an earlier training helps to protect kids from developing bladder problems later in life (Barone et al 2009; Bakker 2002, Bakker et al 2002).

For more information, see my article on what scientific studies tell us about the timing of potty training.

Summing up: How does timing matter?

Based on current evidence, an early potty training age does not lead to behavioral problems. And an earlier start can bring many benefits, including reduced rates of diaper rash, urinary tract infections, and stool toileting refusal. But this does not mean that a child’s age has no effect on the training process. Timing has profound implications for your goals and methods.

On the one hand, younger children

  • have fewer motor skills,
  • are less able to articulate their needs, and
  • have more frequent bladder voidings (Gladh et al 2000; Yeung et al 1985)

This means that earlier training requires more adult supervision. The training process itself may also take longer (Blum et al 2003). And for the youngest children, early training means basic training only. You can’t expect a baby to walk to a potty chair and remove her pants!

On the other hand, older children have spent more of their lives wearing diapers. As a result, they

  • have learned to ignore body signals and must relearn them
  • have become used to wearing soiled diapers and may resist change
  • are more independent and more likely to test your authority
  • have more odiferous urine, making their accidents less pleasant to clean

A late starting age might also put kids at an increased risk for developing problems with incontinence and infections (Barone et al 2009; Bakker 2002, Bakker et al 2002)

The takeaway?

If your child suffers from any urinary tract disorders (including incomplete emptying of the bladder and urinary tract infections), it’s a good idea to pick an earlier potty training age (Bakker 2002).

It’s also important to match your toilet training goals to your child’s abilities. Otherwise, experts agree that you should wait until your child is

  • healthy (no diarrhea or constipation, for example)
  • relaxed (not stressed by new changes, like a move or new baby),
  • cooperative (not going through a rebellious phase)

Beyond this, your choice of timing (as opposed to method) is unlikely to cause any long-lasting behavior problems.

For some parents, getting rid of diapers--and potentially reducing the risk of urinary tract problems--is worth the trouble of an earlier potty training age. For others, the convenience of diapers overrides the potential drawbacks.

Copyright © 2006-2020 by Gwen Dewar, Ph.D.; all rights reserved.
For educational purposes only. If you suspect you have a medical problem, please see a physician.

References: Choosing the right potty training age

American Academy of Pediatrics. 1999. Toilet Training Guidelines: Parents−−The Role of the Parents in Toilet Training. Pediatrics 103;1362

 Bakker E; Wyndaele JJ. 2000. Changes in the toilet training of children during the last 60 years: the cause of an increase in lower urinary tract dysfunction? British journal of Urology, 86(3):248-52.

Bakker W. 2002. Research into the influence of potty training on lower urinary tract dysfunction. Unpublished MD dissertation, Department of urology, University of Antwerp, Belgium.

Bakker E, van Gool JD, van Sprundel M, van der Auwera JC, and Wyndaele JJ. 2002. Results of a quaestionaire evaluating the effects of different methods of toilet training on achieving bladder control. British Journal of Urology, 90: 456-461.

Barone JG, Jasutkar N, Schneider D. 2009. Later toilet training is associated with urge incontinence in children. J Pediatr Urol. 5(6):458-61.

Blum NJ, Taubman B, and Nemeth N. 2003. Relationship between age at initiation of toilet training and duration of training: A prospective study. Pediatrics, 111: 810-814.

Boucke L. 2003. Infant Potty Basics. Lafayette, CO: White-Boucke Publishing.

Brazelton TB and Sparrow JD. 2004. Toilet training the Brazelton way. Cambridge, MA: deCapo Press.

Canadian Pediatric Society. 2000. Toilet learning: Anticipatory guidances with a child-oriented approach. Paediatrics and Child Heath, 5: 333-5.

deVries MW and deVries MR. 1977. Cultural relativity of toilet training readiness: A perspective from East Africa. Pediatrics, 60: 170-177.

Duong TH, Jansson UB, Holmdahl G, Sillén U, Hellström AL. 2013. Urinary bladder control during the first 3 years of life in healthy children in Vietnam--a comparison study with Swedish children. J Pediatr Urol. 9(6 Pt A):700-6.

Gesell A and Ilg FL. 1943. Infant and child in the culture of today: The guidance of development in home and nursery school. New York: Harper and Brothers.

Gladh G, Persson D Mattsson S and Lindstrom S. 2000. Voiding pattern in healthy newborns. Neurourology and urodynamics, 19: 177-184.

Horn IB, Brenner R, Rao M, and Cheng TL. 2006. Beliefs about the appropriate age for initiating toilet training: Are their racial and socioeconomic differences? Journal of Pediatrics, 149: 165-168.

Horstmanshoff BE, Regterschot GJ, Nieuwenhuis EE, Benninga MA, Verwijs W, and Waelkens JJ. 2003.[Bladder control in 1-4 year old children in the the Eindhoven and Kempen region (The Netherlands) in 1996 and 1966]

Largo RH, Molinari L, von Siebenthal K, and Wolfensberger U. 1996. Does a profound change in toilet-training affect development of bowel and bladder control? Dev Med Child Neurol. 38: 1106-16.

Martin JA, King DR, Maccoby EE, and Jaklin CN. 1984. Secular trends and individual differences in toilet-training progress. Journal of Pediatric Psychology 9: 457-468.

McKeith R. 1973. How children become dry. Child Dev Med., 48/49: 3-32.

Schum TR, Kolb TM, McAuliffe TL, Simms, MD, Underhill, RL and Lewis M. 2002. Sequential acquisition of toilet-training skills: A descriptive study of gender and age differences in normal children. Pediatrics 109: 48-54.

Schmidt BA. 2004. Toilet training: Getting it right the first time. Contemporary Pediatrics, 21: 105-119.

Sears RR, Maccoby EE, and Levin H. 1957. Patterns of childrearing. Evanston, Ill.: Row, Peterson and Company.

Sears W, Sears M and Watts Kelly C. 2002. You can go to the potty. Boston, MA Little, Brown and Company.

Taubman B. 1997. Toilet training and toileting refusal for stool only: A prospective study. Pediatrics, 99: 54-58.

Yeung, CK, Godley ML, Ho, CK, Ransley PG, Duffy PG, Chen CN, Li AK. 1995. Some new insights into bladder function in infancy. British Journal of Urology, 76:235-40.

Content last modified 9/2015