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Pregnancy Weight Gain Calculator

Recommended pregnancy weight gain by pre-pregnancy BMI (IOM), with the expected gain at your current week.

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All Pregnancy & baby tools →
Pregnancy CalendarA week-by-week pregnancy timeline with dates and trimesters, with your current week highlighted.Pregnancy Calorie CalculatorDaily calorie needs during pregnancy — TDEE plus the trimester allowance (+340 in T2, +450 in T3).Pregnancy week calculatorFind your current pregnancy week and trimester from your last period.Baby Growth Percentile CalculatorWeight, length and head circumference percentiles from the WHO Child Growth Standards, 0-24 months.Baby Milk Intake CalculatorBottle volumes per feed and per day by your baby's weight and age, with the feeding interval.Gestational Age CalculatorGestational age in weeks and days from your LMP, due date or conception date, with trimester and EDD.hCG Doubling Time CalculatorCompute the doubling time and percentage rise between two hCG results, read against the expected range for the level reached.Implantation CalculatorDate the 6-to-12-day implantation window from your last period or a known ovulation date, with the peak days, the earliest reliable test date and the expected period.

Pregnancy Weight Gain Calculator works straight from this page — free, instant, nothing to install. It sits under Pregnancy & baby in our catalogue, alongside Pregnancy Calendar and Pregnancy Calorie Calculator.

How to use it

  1. Open the tool — no signup or install needed.
  2. Enter your input or adjust the available options.
  3. Get your result instantly, then copy or download it.

Frequently asked questions

What does Pregnancy Weight Gain Calculator do?

Recommended pregnancy weight gain by pre-pregnancy BMI (IOM), with the expected gain at your current week.

When would I actually use this?

Placing a pregnancy on the calendar: the estimated due date, the current week, and when the usual appointments and screenings fall.

What is the most common mistake?

Reading the due date as a deadline. It is a median: fewer than one birth in twenty happens on it, and a normal term spans several weeks around it.

How is Pregnancy Weight Gain Calculator different from Pregnancy Calendar?

They sit next to each other but answer different questions: Pregnancy Calendar is the one to open when you need it to a week-by-week pregnancy timeline with dates and trimesters, with your current week highlighted. Pick whichever matches what you're starting from — both are free.

Is there a tool for the next step?

Pregnancy Calorie Calculator is the closest one after this: Daily calorie needs during pregnancy — TDEE plus the trimester allowance (+340 in T2, +450 in T3).

What else is worth having open alongside it?

Pregnancy week calculator and Baby Growth Percentile Calculator — they come up in the same task often enough to be worth a second tab.

Where do the figures come from?

Dating follows Naegele's rule (280 days from the last period) or the transfer date for assisted conception. An early ultrasound is more accurate than any calculation and takes precedence over it.

Further reading

All guides →
GuideHow Much Weight to Gain in Pregnancy: The Guidelines by Starting BMIThe recommended range depends entirely on your BMI before pregnancy: 28 to 40 lb if you started underweight, 11 to 20 lb if you started with obesity. Here is the full table and the weekly rate behind it.GuidePregnancy Week by Week: The Calendar and What Each Stage MeansPregnancy is counted in 40 weeks from your last period, not from conception — so you are already two weeks pregnant at conception. Here is the full calendar, the trimester boundaries and what term actually means.ExplainerHow Pregnancy Dating Actually WorksGestational age is counted from your last period, about two weeks before conception, so a pregnancy of 6 weeks contains an embryo of about 4 weeks. Here is Naegele's rule derived, the correction for a cycle that is not 28 days, and when ACOG says an early scan should replace your dates.ExplainerHow Much Milk Does a Baby Need? The Rule of Thumb and Its LimitsA formula-fed baby takes roughly 2.3 fl oz per pound of body weight per day in the first months, split across the day's feeds. Here is the table by age and weight, why breastfed babies are not measured this way, and the signs that outrank any number.ExplainerIVF Dating Is the One Case Where the Date Is Actually KnownEvery other pregnancy is dated from an estimate. After IVF, fertilisation is timed to the hour, so gestational age is arithmetic: 266 days from fertilisation, minus the embryo's age at transfer. Here is the derivation for day-3, day-5 and day-6 embryos, why frozen and fresh transfers use the same rule, why an early scan rarely moves an IVF date, and what the two-week offset on a scan report means.ExplainerEating for Two Is About Three Hundred Calories — and Almost None of Them in the First TrimesterThe extra energy a pregnancy costs is far smaller than the phrase suggests, and it arrives on a schedule: near zero in the first trimester, modest in the second, real in the third. Here are the published increments from EFSA, FAO/WHO/UNU and the 2023 US reference intakes, what they look like as food, and why protein and folate rise proportionally faster than calories do.