Pregnancy & Baby Calculators

Estimate your baby’s due date from your last period (with your cycle length), conception date, IVF transfer, an ultrasound or a known due date — with how far along you are, your trimester, a milestone timeline and a week-by-week calendar.

Estimate when conception likely happened — from your due date, last period, an ultrasound or a baby’s birth date — with the fertile-window range, the most likely days, implantation and an early-pregnancy timeline.

Find your estimated ovulation day, fertile window, peak days and next period from your last period and cycle length — with a luteal-phase setting, irregular-cycle range and a table of your next six cycles.

See your fertile window, ovulation day and peak days from your last period, cycle length and luteal phase.

Find out how many weeks and days pregnant you are — from your last period, due date, conception, IVF transfer or an ultrasound — with your pregnancy week, month, trimester, days remaining and a milestone timeline, today or on any date.

See which trimester you’re in and the exact date ranges of all three trimesters, based on your last period.

Work out your hCG doubling time and percent rise from two blood-test values and the hours between them.

Recommended pregnancy weight gain for your pre-pregnancy BMI (IOM 2009), for one baby or twins: the total range, how much by your current week, your target weight range now, a week-by-week chart and table, and a check of your current weight against the range.

Predict your next periods — start and end dates for up to 12 cycles, how many days away, your fertile window and ovulation, today’s cycle day and how late a period is — from your last period, or from a list of past start dates to work out your average cycle and its range.

Work out a premature baby’s corrected (adjusted) age from the birth date and original due date, alongside chronological age.

Plan your maternity leave dates — start, last day off and return to work — from your due date and leave length.

Estimate the day conception most likely happened from your due date, last period or a dated ultrasound — with the fertile window it fell inside.

Work out gestational age in weeks and days on any date — from your last period or from a dated ultrasound measurement.

Enter how many weeks pregnant you are and see your trimester, how far into it you are, and how long until the next one begins.

See the dates of key pregnancy milestones — second-trimester start, anatomy scan, viability, third trimester, full term and your due date — from your last period.

Estimate gestational age and due date from a first-trimester crown-rump length (CRL) using the Robinson–Fleming formula.

Count down the weeks and days left until your due date — with weeks to full term and how far along you are today.

Estimate what percentile an ultrasound estimated fetal weight falls in for its gestational week, using Hadlock reference growth.

Calculate your due date after IVF from the embryo-transfer or egg-retrieval date — for day-3 and day-5 (blastocyst) transfers.

Map your menstrual cycle — period, follicular phase, fertile window, ovulation, luteal phase and likely PMS days — with today’s cycle day and phase, a luteal-phase setting and dates for your next six cycles.

See which days of your cycle are fertile from your average cycle length alone — as cycle-day numbers, no dates needed.

Estimate how much formula or milk a baby needs per day and per feed from body weight, using the ~150 mL per kg guideline.

See a typical postpartum recovery timeline from your delivery date — early days, the six-week checkup and common milestones for vaginal or cesarean birth.

Apply Naegele’s rule — LMP plus one year, minus three months, plus seven days — with an adjustment for cycles longer or shorter than 28 days.

Estimate when implantation happened (or will happen) from your ovulation date or last period — the typical 6–12 day window and the most likely day.

Find the earliest sensible day to test and the day results are reliable, from your ovulation date or last period.

See your baby’s typical length, weight and fruit-sized comparison for any pregnancy week from 4 to 40.

Compare a fundal-height measurement with the expected value for your gestational week (McDonald’s rule) and see whether it falls in the normal ±2–3 cm band.

Daily calories during pregnancy by trimester — Mifflin-St Jeor maintenance plus the recommended extra 0, 340 or 450 kcal.

How much water to drink while pregnant or breastfeeding, from body weight, climate and activity — in litres, cups and glasses.

Time your baby’s movements — minutes to reach 10 kicks, movements per hour, and whether the count meets the usual “10 in 2 hours” guideline.

Add up today’s coffee, tea, cola and chocolate against the 200 mg pregnancy caffeine limit and see how much room is left.

Turn a birth date into an exact age in weeks and days, months and total days — on any date — with corrected age for premature babies, the next check-up or vaccination date for your schedule, and week-by-week and month-by-month birthday dates.

How many diapers your baby will use per day, week and month at each age — plus the total for the first year and a cost estimate.

Predict a child’s adult height from both parents’ heights (Tanner mid-parental method) with the usual ±8.5 cm target range.

Due date and the guideline delivery window for twins or triplets — by chorionicity (dichorionic, monochorionic-diamniotic, monoamniotic), ACOG or NICE timing, from your last period, a scan, an IVF transfer or a known due date — with how far along you are, a twin-specific milestone timeline and a week-by-week calendar.

Work out your luteal phase length from ovulation and next-period dates (or cycle length), and see whether it falls in the typical 12–14 day range.

Expected weight gain at your current pregnancy week from pre-pregnancy BMI (IOM guidelines), compared with what you have actually gained.

How much cow’s milk a toddler should drink each day by age, in ml, ounces and cups — with the calcium it provides and the upper limit to avoid iron deficiency.

Check a beta-hCG result against the typical range for your week of pregnancy (from LMP or days past ovulation) and see where in the range it falls.

Turn an early-scan crown–rump length in mm into gestational age and an ultrasound due date using the Robinson–Fleming formula.

Estimate fetal weight from ultrasound biometry — biparietal diameter, head and abdominal circumference and femur length — with the Hadlock formula and a rough percentile band.

Score cervical readiness for labour induction — dilation, effacement, station, consistency and position — with the modified Bishop score and what it implies for induction.

Work out a premature baby’s corrected (adjusted) age and chronological age in months, weeks and days from the birth date and gestation or the due date, with postmenstrual age, the prematurity category, the date to stop correcting (UK RCPCH rule or age 2 or 3) and a table of corrected-age milestone dates.

Plan maternity leave around your due date — US FMLA (12 weeks), UK statutory maternity leave (52 weeks, earliest start 11 weeks before the due week) or your own scheme: start date from weeks before the due date or a date you pick, last day, return-to-work date, notice deadlines, the UK qualifying week, SMP and compulsory-leave dates, holiday added at the end, and what changes if the baby comes early.

How often and how much a newborn typically feeds by day of life and weight — feeds per 24 hours, hours between feeds, mL and fl oz per feed and per day for formula, breastfeeding or expressed milk, with first-week colostrum amounts, wet and dirty nappy checks, weight change since birth and a sample feeding schedule.

How much formula a baby needs per day and per bottle by weight and age — plus scoops, water and how many tins a month at your brand’s scoop size.

Which baby clothes size fits — by weight and length rather than age — with UK/EU centimetre sizes, US age labels and how long until the next size up.

Convert a measured foot length to baby and toddler shoe sizes — UK, US and EU — with growing room and how soon to measure again.

When to start weaning: the around-6-months date from your baby’s birth date (corrected for prematurity), the not-before-4-months date, readiness signs, allergen introduction, and a month-by-month first-foods timeline with dates for textures, finger foods, three meals and cow’s milk.

Expected arrival dates for each of the 20 baby teeth from your baby’s birth date — which teeth are due now, which are next, and when the set is complete.

UK SMP for 2026/27 week by week — 90% of average earnings for six weeks, then the lower of £194.32 or 90% for 33 weeks — from weekly, monthly or annual pay, with NHS, teacher or custom enhanced schemes, key dates from your due date, pay by calendar month, estimated take-home, employer reclaim and Maternity Allowance if you don’t qualify.

Government Parental Leave Pay — 24 weeks at the national minimum wage, the total before tax, superannuation on the payment, the income test and how it stacks with employer-paid leave.

Estimate New Zealand paid parental leave payments — 26 weeks at your average weekly earnings up to the $788.66 maximum (from 1 July 2025), before and after tax.

How much formula a baby needs per day and per feed from weight and age (150–200 mL/kg/day in the early months), feeds per day, scoops and water per bottle, calories delivered and how many tins a month.

Score the 10-item Edinburgh Postnatal Depression Scale for pregnancy or after birth — total 0–30, the 10 and 13 cut-offs, the self-harm item and the EPDS-3A anxiety subscale.

Estimate newborn gestational age with the somatic Capurro method — skin texture, ear shape, breast size, nipple formation and plantar creases — in weeks and days, with term or preterm classification.

Predict your baby's eye color from the parents' and grandparents' eye colors with a simple two-gene Mendelian model: honest probabilities for brown, green/hazel and blue/gray, and the chance each parent carries a hidden lighter-eye allele.

Look up the traditional Chinese gender chart: we convert the mother's birth date and the conception date to the Chinese lunar calendar, find her lunar age and the lunar month, and show the folklore prediction — plus what the science says.

Find the use-by date and time for pumped breast milk on the counter, in the fridge, cooler or freezer, or after thawing, using CDC storage guidelines — with the full storage chart and safe-handling tips.

See when your baby's growth spurts are likely: dates for the 7–10 day, 2–3 week, 4–6 week, 3, 6 and 9 month growth spurts from the birth date, adjusted for prematurity, plus the next one coming up and what to expect.

Estimate how long to wait after drinking before breast milk is alcohol-free, from your weight, height and drinks, using the Motherisk method (Watson body water and 15 mg/dL per hour elimination), with a table for 1 to 5 drinks.

Calculate your newborn's weight loss as a percentage of birth weight, see whether it is in the expected range (under 7%), needs a feeding check (7–10%) or calls for your pediatrician (10% or more), and the 7% and 10% weights.

Work out how fast your baby is gaining weight, in grams per day and ounces per week, between two weigh-ins, and compare it with the typical range for 0–4, 4–6 and 6–12 months.

Check pregnancy glucose tolerance test results against the official cut-offs: one-step 75 g (IADPSG/WHO), three-hour 100 g (Carpenter–Coustan or NDDG), NICE 75 g and the 50 g one-hour screen, in mg/dL or mmol/L.

Check the USPSTF and ACOG risk factors for preeclampsia — high-risk and moderate-risk — to see whether low-dose aspirin (81 mg from 12–28 weeks) is recommended in your pregnancy.

Estimate gestational age from second- and third-trimester ultrasound measurements — BPD, head circumference, abdominal circumference and femur length — with the Hadlock formulas and an estimated due date.

Calculate mean gestational sac diameter (MSD) from three ultrasound measurements, estimate gestational age in early pregnancy and see the SRU size criteria for an empty sac.

Add the four quadrant pocket depths to get the amniotic fluid index (AFI), plus the single deepest pocket, and see whether the values fall in the oligohydramnios, normal or polyhydramnios range.

Enter how far apart your contractions are, how long each lasts and for how long the pattern has held to check the 5-1-1 rule and see whether it looks like early or active labor.

Count how many days past ovulation (DPO) you are on any date, with your implantation window, the earliest day a sensitive pregnancy test may turn positive and when your period is due.

Use your shortest and longest cycle to find your fertile days with the calendar rhythm method (shortest − 18, longest − 11), the dates for this cycle and whether the Standard Days Method fits you.

Enter 6 low basal temperatures and the next 3 readings to draw your BBT coverline and check the 3-over-6 rule that confirms ovulation has happened, in °C or °F.

Find your target heart rate zone for moderate exercise during pregnancy by age (SOGC/CSEP), with the 10-second pulse count, the talk test and the effort level to aim for.

See how many servings of fish a week are recommended in pregnancy, while breastfeeding or for children by age, the serving size in grams and ounces, and which fish to avoid (FDA/EPA).

Estimate how many weeks it may take to get back to your pre-pregnancy weight at a safe postpartum pace, with a week-by-week projection and calorie floors while breastfeeding.

Estimate the chance of getting pregnant from intercourse on a given day of your cycle, based on your estimated ovulation date and the classic Wilcox day-specific conception probabilities.

Calculate the time between your last birth or pregnancy loss and your next planned conception, and compare it with the WHO and ACOG recommendations on pregnancy spacing.

Check whether a hemoglobin result in pregnancy means anemia, and how severe, using the WHO 2024 trimester-specific cutoffs with the adjustment for living at high altitude.

Calculate the fetomaternal hemorrhage volume from a Kleihauer-Betke test and the number of 300 µg (1,500 IU) vials of Rh immune globulin (anti-D) an Rh-negative mother needs.

Plan a clomiphene (Clomid) or letrozole cycle: tablet days, expected ovulation window, best days for intercourse, ovulation test start, progesterone blood test and pregnancy test dates.

Find the right day for your “day 21” progesterone blood test when your cycle is not 28 days long, and check whether your result confirms ovulation (nmol/L or ng/mL).

Find the date you reach 39 weeks (or 37, 38 or 40 weeks) for a scheduled cesarean birth from your due date, with the weekday, the nearest weekday and the term category.

Check whether breastfeeding can still protect you from pregnancy with the lactational amenorrhea method (LAM): the three WHO conditions, how many days of protection are left and when it ends.

Score the severity of nausea and vomiting in pregnancy over the last 24 hours with the PUQE-24 scale (mild, moderate or severe) and see when to talk to your doctor about hyperemesis.

Add up the fetal biophysical profile: non-stress test, breathing, movement, tone and amniotic fluid, each scored 0 or 2, to get the BPP score out of 10 and its usual interpretation.

See the average chance of having a baby with Down syndrome (trisomy 21) by the mother’s age at delivery, at birth and at 16 weeks of pregnancy, from the classic Hook maternal-age table.