Diaper Size and Weight Chart 2026: How to Choose the Right Size for Your Baby (Complete Guide)

TL;DR

Always choose a diaper by your baby's weight, not their age. In India, diapers use letter sizes (NB, S, M, L, XL, XXL, XXXL), while some international brands use numbers (Size 1 to 6), so the same baby can be two "different" sizes across brands (AAP)。 On the Mylo range, the weights are: NB up to 5 kg, S 4 to 8 kg, M 7 to 12 kg, L 9 to 14 kg, XL 12 to 17 kg, XXL 15 to 25 kg and XXXL 18 to 35 kg. The clearest signs you need the next size up are red marks, frequent leaks, gaps at the waist or legs, or the diaper no longer pulling up comfortably. If your baby's weight falls between two sizes, go with the larger one. Most babies change size every 3 to 4 months.

Quick Answer

Choose a diaper by your baby's weight, not their age. Indian brands use letter sizes (NB, S, M, L, XL, XXL, XXXL) while some international brands use numbers (Size 1 to 6), so always check the pack's weight chart. On the Mylo range: NB up to 5 kg, S 4 to 8 kg, M 7 to 12 kg, L 9 to 14 kg, XL 12 to 17 kg, XXL 15 to 25 kg, XXXL 18 to 35 kg. Size up if you see red marks, frequent leaks or gaps. If the weight falls between two sizes, choose the larger one.

Author: Priyanka Verma, Senior Baby Care Content Editor, Mylo Parenting Desk Reviewed against: AAP / HealthyChildren, NHS and IAP guidance Last updated: 15 July 2026

Medical Disclaimer: This article is for informational purposes only and is not a substitute for professional medical advice. Every baby's build and skin are different. If your baby has a severe rash, blisters, pus, or a rash that does not improve in 2 to 3 days, see your paediatrician.

Key Takeaways

• Choose by weight, not age (AAP)

• Indian brands use letters (NB to XXXL); some international brands use numbers (1 to 6)

• Always check the pack's weight chart, sizes are not standard across brands

• Red marks or frequent leaks mean it is time to size up

• If weight is between two sizes, choose the larger

• Most babies change size every 3 to 4 months

• A bigger size does not mean fewer changes, it means leaks

• Change every 2 to 3 hours, or immediately after a poo

Diaper Size and Weight Chart (Mylo Range)

This is the chart that matters if you are buying in India:

Note: The premium AirPrime range covers Small to XXL. For newborns (NB) and the largest size (XXXL), choose the regular range.

Indian Letter Sizes vs International Number Sizes

This is where most parents get confused. Some international brands label diapers Size 1 to 6, while Indian brands use letters. Here is roughly how they line up:

Important: This is only a rough guide. Weight ranges overlap and differ by brand, which is exactly why you must read the weight printed on the pack, never assume "M is M" across brands.

Why Should You Choose by Weight, Not Age?

Age is only a rough signal. Two babies of the same age can differ by several kilos (AAP):

1. Babies grow at different rates, a 6-month-old may be 6 kg or 9 kg

2. Build differs, some babies are long and slim, others are chubby

3. Premature babies need smaller sizes for longer

4. Weight ranges overlap, so the pack chart is the only reliable reference

The rule: weigh your baby, then match that weight to the pack's chart.

How Do You Know the Diaper Size Is Wrong?

Watch for these clear signs (NHS):

Signs the Diaper Is Too Small

• Red marks on the waist or thighs

• The diaper does not pull up comfortably

• Frequent leaks (a full diaper that cannot hold more)

• The waistband sits below the belly button

• Your baby seems uncomfortable or fussy

Signs the Diaper Is Too Big

• Gaps around the legs or waist

• The diaper sags or slides down

• Leaks despite the diaper being dry in places

• It looks bulky and restricts movement

Either way, leaks are your loudest clue. A diaper that leaks is almost always the wrong size or the wrong fit, not a bad diaper.

How to Choose the Right Diaper Size: 7 Practical Tips

1. Check the pack's weight chart, trust weight over age

2. Consider your baby's build, chubby thighs may need the next size

3. Look for red marks, they mean it is too tight

4. Test the waistband, two fingers should slide in comfortably

5. Check the leg openings, not tight, not gaping

6. Watch for leaks, repeated leaks mean it is time to change size

7. Track growth spurts, expect a size change every 3 to 4 months

What If Your Baby's Weight Is Between Two Sizes?

Choose the larger size. For example, if your baby is 8 kg, they sit at the top of S (4 to 8 kg) and the start of M (7 to 12 kg), go with M.

Why the larger size works better:

• A too-tight diaper causes red marks and rashes

• The bigger size gives more absorbency

• Your baby will grow into it within weeks

But do not jump two sizes. A much bigger diaper gaps and leaks, which defeats the purpose entirely.

How Often Should You Change a Diaper?

Regardless of size (NHS) (AAP):

• Every 2 to 3 hours during the day

• Immediately after a poo (the biggest cause of rash)

• Before bedtime

• After a bath

• Whenever the wetness indicator changes colour

A bigger size does NOT let you change less often. Prolonged wetness against the skin is what causes rashes, whatever the size.

Which Mylo Range Should You Choose?

Both ranges give up to 12 hours of protection and both contain Aloe Vera. The difference is thickness, breathability and skin care:

Indian Context: What Indian Parents Should Know

1. Letter sizes, not numbers: Indian packs use NB to XXXL; do not go by international Size 1 to 6 charts (IAP)

2. Heat and humidity: In Indian weather, breathability matters more than thickness

3. Weigh your baby: Use immunisation visits to note the current weight, then match the pack chart

4. Jumbo packs are better value: Both ranges offer multi-packs at a lower per-diaper cost

5. Do not size up to save money: Oversized diapers leak, costing you more

6. Stick to what suits: Frequent brand switching can irritate sensitive skin

Myths vs Facts About Diaper Sizes

FAQs: Diaper Size and Weight Chart

How do I know what diaper size my baby needs?

Go by your baby's current weight and match it to the weight chart printed on the pack, not their age (AAP)。 On the Mylo range: NB up to 5 kg, S 4 to 8 kg, M 7 to 12 kg, L 9 to 14 kg, XL 12 to 17 kg, XXL 15 to 25 kg, XXXL 18 to 35 kg.

Baby ka diaper size kaise pata karein? (Hinglish)

Diaper size hamesha bachche ke wazan se chunein, umar se nahi, aur pack par diya weight chart zaroor dekhein. Mylo mein NB = 5 kg tak, S = 4 se 8 kg, M = 7 se 12 kg, L = 9 se 14 kg, XL = 12 se 17 kg, XXL = 15 se 25 kg hai. Agar kamar ya jangh par laal nishaan hain ya baar-baar leak ho raha hai, toh agla size lene ka time aa gaya hai.

What should I do if my baby's weight is between two sizes?

Choose the larger size. For example, at 8 kg your baby sits between S (4 to 8 kg) and M (7 to 12 kg), so pick M. A tight diaper causes red marks and rashes, and your baby will grow into the larger one quickly. Just do not jump two sizes, that causes gaps and leaks.

How do I know it is time to size up?

The clearest signs are red marks on the waist or thighs, frequent leaks, gaps at the legs or waist, or the diaper not pulling up comfortably (NHS)。 Most babies change size every 3 to 4 months.

Diaper leak kyun hota hai? (Hinglish)

Leak ki sabse aam wajah galat size hoti hai. Agar diaper chhota hai toh woh poori tarah sokh nahi pata, aur agar bahut bada hai toh leg aur waist par gap reh jata hai jahan se leak hota hai. Doosri wajah hai bahut der tak na badalna. Sahi size chunein aur har 2 se 3 ghante mein badlein.

Are diaper sizes the same across all brands?

No. Weight ranges differ between brands, so the same baby can be "M" in one brand and "L" in another (AAP)。 Never buy on the letter alone, always check the weight range printed on the pack.

Can I use a bigger diaper so I change it less often?

No. An oversized diaper gaps and leaks, and prolonged wetness against the skin causes rashes regardless of size (NHS)。 Change every 2 to 3 hours, and immediately after a poo.

Which Mylo diaper size is available in the premium range?

The AirPrime premium range is available from Small to XXL. For newborns (NB) and the XXXL size, choose the regular Mylo Baby range, which covers NB to XXXL.

References

1. AAP / HealthyChildren. "Diapers and Clothing." https://www.healthychildren.org/English/ages-stages/baby/diapers-clothing/Pages/default.aspx

2. NHS UK. "Nappy Rash." https://www.nhs.uk/conditions/nappy-rash/

3. American Academy of Dermatology (AAD). "Diaper Rash: Treatment." https://www.aad.org/public/diseases/a-z/diaper-rash-treatment

4. Indian Academy of Pediatrics (IAP). https://iapindia.org/

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