⚠️ Medical Disclaimer: These tools are for educational purposes only and are not medical advice. Please consult your GP, health visitor, or NHS healthcare provider for any health concerns.
Free Tool

Baby Size Comparator. Week by Week

How big is your baby this week? Slide to your pregnancy week and instantly see your baby compared to a fruit or vegetable. With weight, length, and what's developing right now. Perfect for sharing with family!

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For UK mums, the NHS provides two main scans during pregnancy, and the weekly size comparison helps you visualize whats happening between scans. From poppy seed to watermelon, the journey is fascinating. This comparator shows your babys size at each week using comparisons familiar to UK households. We follow NICE guidance for fetal growth and align with NHS information.

🍓 Fruits and objects familiar in the UK

We compare to fruits and objects you find at Tesco, Sainsburys, ASDA, Waitrose, or Marks and Spencer: poppy seed, blueberry, kumquat, plum, lime, mango, butternut squash, marrow, pumpkin, watermelon. Plus household items like 50p coin, golf ball, cricket ball. Standard NICE and Royal College of Obstetricians and Gynaecologists biometry charts back the measurements. Your midwife and sonographer use NHS standard ultrasound biometry at the dating and anomaly scans.

🤱 Baby Size Comparator. Week by Week

See how big your baby is this week. Compared to fruits and vegetables you know 🍋🍉

Week 4 Week 40
WEEK 20
🍌
Banana
🗓️ Quick Week Navigation
Step-by-Step Guide

How to use this tool

Drag the slider to your current pregnancy week and instantly see your baby's size comparison, weight, length and development highlights.

  1. 1
    Drag the slider to your pregnancy week

    The slider goes from week 4 (implantation) to week 40 (due date). Drag it to your current week to see your baby's size comparison. If you are not sure of your week, use the Due Date Calculator first.

  2. 2
    See the fruit comparison and stats

    The large emoji and name shows what fruit or vegetable your baby is roughly the same size as this week. The three boxes below show the exact week number, average baby length in centimetres, and average weight in grams or kilograms.

  3. 3
    Read the development description

    Below the stats is a paragraph describing what is happening inside your womb this specific week. What organs are forming, what your baby can sense, and what major milestones are being reached.

  4. 4
    Use the quick navigation buttons

    Tap any of the quick navigation buttons (12 weeks, 16 weeks, 20 weeks etc.) to jump to key milestones. Share a screenshot on WhatsApp with the message "My baby is a mango this week!". Friends and family love it.

💡 Take a weekly photo with the fruit

A fun pregnancy tradition: take a photo every week holding the fruit your baby is compared to. By the end of 40 weeks, you have a beautiful collection showing your whole pregnancy journey from poppy seed to watermelon. This makes a wonderful memory book.

⚠️ These are average sizes only

All measurements shown are averages for that gestational age. Your baby's actual size may be slightly larger or smaller. Both are completely normal. Small or large ultrasound measurements only become a concern if they are significantly outside the normal range across multiple scans. Always discuss ultrasound measurements with your doctor.

FAQ

Frequently Asked Questions

In the first 20 weeks, babies are measured from crown (top of head) to rump (bottom). Called CRL (Crown-Rump Length) because legs are curled up. After 20 weeks, babies are measured from crown to heel. Called CHL. This is why the measurements shown seem to jump significantly around week 20-21. It is a change in measurement method, not sudden growth.
The average birth weight for British newborns is approximately 2.8 kg, which is slightly lower than the global average of 3.3 kg. Low birth weight (under 2.5 kg) is more common in the UK due to maternal nutrition and socioeconomic factors. A healthy British newborn typically weighs between 2.5 kg and 3.5 kg. Weight below 2.5 kg at birth requires paediatric monitoring.
No. Ultrasound measurements have a margin of error of ±1-2 weeks. Your baby may simply be slightly smaller or larger than average. Which is perfectly normal. Growth concern arises when measurements are consistently below the 10th percentile across multiple scans, or when growth slows significantly between two scans. Your doctor will flag any actual concerns.
Most first-time mothers feel baby movements (called quickening) between 18-25 weeks. Experienced mothers often feel movements earlier, around 16-18 weeks, because they recognise the sensation. Baby movements feel like gentle flutters, bubbles, or a light tapping at first. By 28 weeks, you should feel at least 10 movements in 2 hours daily. Contact your doctor if movements reduce significantly.
Healthcare in UK

How prenatal scans actually work in the UK

UK pediatric care runs through the NHS. Generally well organised. Can feel slow at peak times. Your first call is usually NHS 111. Free, 24/7. They triage what is going on and tell you what level of care to seek. Sometimes a GP appointment via e-Consult. Sometimes A and E. Occasionally an ambulance. Out of hours GP services run evenings and weekends. Walk in centres and Urgent Treatment Centres handle the mid range stuff. A and E is for genuine emergencies, not routine fever queries, where you can wait many hours. For babies under 3 months though, A and E is the right call regardless. The NHS Pharmacy First service can also handle minor childhood things now without a GP appointment.

📞 Emergency contacts in the United Kingdom

In the UK, call NHS 111 for non-emergency advice 24/7. For emergencies, call 999. Your Health Visitor is a valuable resource during weekday hours. Pharmacies like Boots offer free advice through the Pharmacy First service. Many GP practices have an after hours triage line.

Context for British families

What British mums actually deal with

British mums often feel pressure to wait it out before bothering the NHS. This is wrong thinking. NHS 111 was designed for exactly these calls. Staff are trained to triage and there is genuinely no judgment for calling. Health Visitors are an underused resource. They expect to hear about concerns in young babies. They can advise on what is normal during teething (mild temperature elevation, yes). True fever above 38 Celsius is something else and worth a proper assessment. British medical practice runs more conservative on medication than American practice. Calpol is the workhorse. Talk to your GP or pharmacist before alternating with Nurofen, NICE specifically does not recommend routine alternating.

More FAQs for UK

British-specific questions

Standard NHS care includes two scans: the dating scan around 10 to 14 weeks and the anomaly scan at 18 to 21 weeks. Additional growth scans are arranged if there are concerns (small baby, big baby, mother with diabetes, multiple pregnancy). Most areas no longer routinely do a third trimester growth scan unless indicated. Private scans for additional reassurance or 3D imaging are widely available (typically 80 to 200 GBP at clinics like Babybond, Window to the Womb). Some parents choose private scans for additional reassurance or gender determination earlier.
The NHS anomaly scan at 18 to 21 weeks can tell you the sex in most cases. NHS policy varies by trust on whether sonographers will share this information. Some trusts will tell you on request, others have a strict no policy. If you want to know, ask your midwife before the scan what your local trust policy is. Private gender scans from around 16 weeks cost 60 to 90 GBP. NIPT (non invasive prenatal test) from around 10 weeks can determine sex and is available privately (200 to 400 GBP) or sometimes via the NHS for high risk pregnancies.
Your community midwife handles ongoing antenatal care between scans: blood pressure, urine checks, fetal heart rate listening with a Pinard or Doppler, abdominal palpation to feel baby position, symphysis fundal height measurement (measuring your bump from pubic bone to top of uterus), and discussion of how you and baby are doing. The midwife appointments complement the two scans. If the midwife identifies any concerns (large or small for dates, reduced movements), she will refer you for additional scans. The system works well for most pregnancies.
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