When do newborns regain their birth weight? How to keep a log of early weigh-ins

A 2025 NHS Scotland guideline on weighing newborns says that a healthy baby should be back at birth weight by around 14 days, and certainly before 21 days. The same guideline says the older idea that babies lose up to 10% is out of date, and that in most babies the loss is more likely to be around 5 to 7% of birth weight.

Other NHS services give similar timings, and some local trusts use different thresholds for when to look more closely. So treat any number in an article, including this one, as background, and use the figures your own midwife or health visitor gave you.

A baby who is not yet back at birth weight at two weeks is not automatically in trouble, and a baby who is back early is not automatically doing better. What the care team looks at is the direction of travel, together with feeding, diapers and how your baby seems.

Weight is one of the few things the clinic measures that you cannot judge by eye. In the early days your midwife or health visitor usually weighs your baby on calibrated scales and compares each result with the birth weight. Each of those numbers is easy to lose: they are given out loud at an appointment, sometimes in grams and sometimes in pounds and ounces, often while you are holding a baby.

Writing them down as you hear them lets you answer the question that follows: is my baby heavier than at the last weigh-in?

Keep one short table, with a row per weigh-in:

• The birth weight, in the first row, copied from the hospital or birth record.
• The date, and your baby's age in days.
• The weight, in the same unit each time. If the clinic says 3,420 g, write 3.42 kg; if they say pounds and ounces, convert once and keep the same unit.
• Where it was weighed. Home scales and clinic scales often disagree, so do not compare one with the other.
• What the midwife or health visitor said, and when the next weigh-in is.

Add a line about feeds and diapers for the same days. Weight is one piece of the picture, and the log of feeds and diapers is what you will be asked about next. Our guides on wet diapers and on whether your baby is getting enough milk explain what to note.

Tap Growth on the Today screen, type the weight, set the date and time of the weigh-in, and save. The weight field follows your measurement setting, in kg or lb, and there is a note field where you can write where it was weighed and what you were told. Length and head circumference are optional.

Baton does not have a birth weight field and does not calculate the change since birth: copy the birth weight in as the first entry, dated the day of birth, and subtract in your head or on paper. If you have set your baby's sex, each entry also shows where it falls on the WHO growth standards. That is a percentile for the baby's age, not a check on weight loss, and it is information rather than a diagnosis.

On the free plan Baton shows the newest measurement on the WHO chart and keeps every entry; seeing all earlier measurements on the chart and in History is part of Baton Plus. CSV export of all entries is free. Both parents see the same entries through their own iCloud.

Contact your midwife, health visitor or pediatrician if your baby has not been weighed when you were told to expect it, if the weight has gone down since the last weigh-in, if your baby is not back at birth weight when you were told to expect it, or if you are worried about feeding. Also call if there are few wet diapers, dark urine, or a baby who is unusually sleepy and hard to wake for feeds. Do not wait for the next appointment. Bring your table, and your feed and diaper log. In an emergency, call your local emergency number.