Using Growth Charts to Predict Diaper Needs

Over at the nifty Thrifty Mommy blog, Kelly posted about how she stocks up on diapers before the baby is born. She recommends buying diapers of various sizes weekly.

Kelly’s post made me remember how confusing it was when I was pregnant to figure out how best to stock up on diapers. Then I realized it might be helpful to use a growth chart to predict the weight (and thus diaper size) of a baby at a certain time. So using CDC growth charts for both girls and boys’ weight, I’ve done some number crunching. Here’s an estimate of how many jumbos of each size you may need if you plan on stocking up.

My son’s weight is only in the 5th percentile, so I know that these charts can’t predict the weight of every baby. You’re child’s build will have an awful lot to do with how a diaper fits, too. That said, I think the growth charts are a way to form an educated guess about how many packs of each size diaper to stock up. If you’re kid is in the 25th percentile for weight rather than the 50th, for example, just substitute that info for what I have here.

The most frugal way to diaper a baby (using disposables) is to keep the baby in the smallest size you can for as long as you can. The info below takes this into consideration. I’ve never had a problem switching out a pack of one size for a pack of another size, even without a receipt, so in case you buy too many of a smaller size, just exchange the leftovers.

Size N: 6 or 7 jumbos
Size N diapers generally go up to 10 lbs. You’ll change diapers OFTEN. Buy about a month’s worth.

Size 1: 15+ jumbos
Size 1 diapers generally go up to 14 lbs. The baby will reach this weight at about 3.5 months.

Size 2: 25+ jumbos
Size 2 diapers generally to up to 18 lbs. The baby will reach this weight at about 7 months.

Size 3: 70+ jumbos
Up to 28 lbs. The baby will reach this weight at about two years old. You’ll be in size 3s for a LONG time.

Size 4: 40+ jumbos
Hopefully this is the last size you’ll need. Most kids will use this size until they’re potty trained.

Shocked at how many diapers you’ll be buying? If you use disposables you’ll probably spend more than $1500 on diapers before your child is potty trained and buy enough jumbos to fill your house up a couple of times over.

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  1. Pamela M says:

    This is a great planner, but cloth diapers are the TRUE cheapskate way to go! Buy each size once and use them for multiple children, buy used or buy the adjustable size ones. Use the rolls of “bio paper” to catch the poo if you’re really concerned about it, flush that and wash the diapers. You’ll have far fewer leaks and blowouts, and no diaper rash. Buy your laundry detergent in bulk and you’re good to go! It’s easier than most people think!

  2. Crystal says:

    I will say that our LO is only 16 months and ever since 22 lbs (bout 25? Lbs now), he’s been in size 5’s. It seems like we were in size 4’s for a moment then size 5’s. He has room to grow but they seem like a better fit covering more of the backside and never having a leak/issue. In our case, we rather have a little bigger than snug so no ‘accident’ coming out. 🙂

  3. My son has been in 5s the longest. He wore 4s for a while, but we’ve been in 5s since he was about 7 months old. He’s 1, weighs 24.6 pounds, but he’s a long and round wiggle worm. 4s just leaked! I can’t believe how quickly he went up in diaper sizes!

  4. mom2two says:

    Great list, however, I have an average 4 month old and he’s already in size 3 diapers…this list would have left me with a closet full of diapers i couldn’t use. You also never know which ‘brand’ of diaper will work best for your baby. As for sizing, my son was just shy of 8lbs, we never used N’s…size one starts at 8 lbs…all sizes overlap and we were always out of the lower size before the weight limit and into the next at the beginning of it’s weight range. All babies are different, but I would never stock up like this. If there’s concern for finances and buying diapers, then buy yourself a gift card every week leading up to the birth of your child…In summary: I don’t recommend over buying diapers for multiple reasons: you don’t know how big (or little) your baby will be and you don’t know which brand will work best for your babes tush.

  5. Shawna says:

    Wow, that is ALOT of size 3’s. We used size 3 for maybe 2 months. She has been in size 4’s for about a year now, though.

  6. lora says:

    my baby was born @ 8lbs. wore NB for 3 weeks, wore size 1 until 2mo. Went to size 2 at 2mo and is not 3mo and weighs 12lbs and wears size 2. She will probably be in size 3 in a few months.

  7. Jen says:

    My son never used NB size, and has been in size 6’s for the past 9 months (he is now 2 1/2). Sizes 3 and 4 were the sizes he was in the least!

  8. Rosie says:

    thanks for the break down. Every kid is different, for sure, (my daughter was in 2s for at least 6 months, DS was only them them for a month or 2… he was 6 months when we put him in 3s while DD was nearly a year before getting to 3s, then potty-trained out of them) but this is at least helpful. I’m due this December and am stocking up on dipes for new baby whenever I can get them for under $4 a pack. Do I run the risk of having a big baby who can’t use all those 1s, or a tiny baby who need twice as many 1s? Yep, but this at least gives me something to go off of. And I have also never had trouble exchanging diapers for a different size, except once at Walgreens.

  9. Thank you for sharing this post. What a great idea to compare the size with the growth chart.

    My daughter was very large after she was born. She weighed a normal weight at birth but grew so fast that she ended up in size 3s for a couple months stayed in 4s for long time, then up to 5 and before I knew it at 18 months she was in size 6! I thought for sure I had to buy size 7. I was new to stockpiling diapers and I would get what I knew what fit her and what I would need. She then thinned out and went back to size 5. Back in 2010, I tracked the cost of the diapers for the year HERE.

    My stockpile price is under 20 cents a diaper.

    I just had identical twin boys and was determined to have a great stockpile ahead of time. I even had a diaper party and asked for larger sizes. I suggest asking for size 3,4,5 or 6 at a diaper party.

    I bought a lot of diapers at the Babies R Us black friday sale and I also used the coupons in the boxes for more Babies R Us diapers when they were on sale. This is a great way to stockpile and is cheaper than Amazon. Now that Amazon Mom is going away. Big bummer!

    You mentioned returns. Unfortunately, I have had problems with returns at most stores these days. Babies R Us was the worst. They wanted me to PAY for the diapers rather than a straight exchange. It was awful! More info HERE. Even though I plan on still purchasing items from Babies R Us I will be much better about the 90 day return policy with or without a receipt.

    CVS and Walmart are the best places to exchange diapers for sizes in my experience. You just have to make sure they “sell” that size and since so many sizes are being changed it is more difficult.

    Costco is the BEST for returns including diapers. In my opinion they cost a lot for diapers there. I got several boxes at the diaper party and I knew the boys were growing so fast I would return them for a cash card and use the money for other sizes (on sale) or for food.


  10. Jennifer says:

    This sizing scale seems a little off for me. My 6.5mo old (weighing in @ 24#), and my 2 yr old (weighing in @ 28#) are both comfortably wearing Huggies Snug and Dry Size 5. Size 4 were just leaking out the tail-end of my baby. My 2yr old didn’t have enough coverage in the front or back with the size 4. Maybe my kids are just made weird 🙂

  11. Chase says:

    So for a total newbie… how many diapers are in a jumbo pack? Seems like the different brands have different #’s associated with ‘jumbo’?

  12. The number of diapers in a jumbo pack varies by size. The larger the size, the fewer diapers per pack. Per size, the quantity remains pretty much uniform across premium brands (Pampers Swaddlers, Huggies Little Snugglers). Size 3 jumbos in those brands have 31 diapers for example. It does get complicated, doesn’t it!

  13. tiffany says:

    how man diapers are in jumbo sizes all the way up to size 4?

  14. Courtney says:

    Thanks for this! I have 3 year old twins and am expecting my next set in about a month. We never went above a size 4 with my 3 year olds (now potty trained), who were always at or above the average size for their age.

  15. Becky says:

    This is a nice list, however, my LO was 14 lbs at 2 months. He’s now bordering 16 lbs and 3 months. Entering size 3s.

  16. kristen says:

    When I was stocking up I had calculated nearly exactly the same list. My daughter was born at 6lbs 9 oz and it worked perfect for us. If were were ever off by a pack or two I’d take them back to the store and exchange for the next size. We never made it to a size 4, we switched to pull ups instead for potty training.

  17. Kim says:

    Our son has been off the top of the charts for height & weight since 2 weeks after he was born. Both Daddy & I are over 5′ 10″, and proportional to our height, so he comes by his size honestly. He never used newborn, was in 1’s for a month, then 2’s for a month, then 3’s for a month. At 4 months old, he was in size 4’s – his size was his age for too long. He’s now 6 months & still in size 4s, thankfully, as he’s slowing his growth for a bit. 23 lbs at 6 months is a bit big!

  18. Ivy M says:

    I am stocking up on diapers because we are going through fertility treatments so every penny saved counts! I also coupon so I will only get the diapers when they are less then $2 or $3 a pack. I have 4 new born, and 15 each of size 1,2,3. Should I start buying 4s that are slip ons. Not the pull ups because I know they differ with sex but the huggies slip ons. I would like to stock up as much as I can. Thanks!

  19. MidwestMomma says:

    Personally, I think the pull-on diapers are a joke. You have to lay baby down to take the dirty diaper off & if they are really that wiggly of a kid, they’re going to make a mess if you try to take it off standing…and how do you get a clean wipe on a running tush?? By the time they’re in size 4’s, you’ll be a diaper changing pro & it won’t take but a minute anyway.

    Just my opinion, but I think they are more of a marketing gimmick than a useful product.

  20. Michigan Mom says:

    I know several people who use cloth diapers. I agree that they are more economical in some ways. Unfortunately, our baby is in a daycare setting, and we can’t go that route. Also, I don’t think I can get the water in my machine hot enough to sanitize, and I would rather avoid using bleach. Our compromise has been to use Target brand diapers. I find I can get them cheapest, even over major brands with coupons and on sale. They work great and we have been very pleased. Also, our rule of thumb is that when the wetting and blowouts become frequent, time to move up a size. If we have a open package of the smaller size, we donate the leftovers to a shelter.

  21. mims says:

    my one month old is about to graduate to size 2s next week. he was born at 7.5 pounds. ya just never know!

  22. Jamie says:

    My daughter was born at 8# 10 oz and was in NB for mabye 2 weeks, 1 for a month then basicaly skipped 2’s and right into 3’s for the next month and is now already blowing out of those at 9 weeks old. Just tried her in a 4 and it fits pretty well. She’s 99% for height, weight, and head circumfrence though. 15# 8oz and almost 25″ long at 9 weeks is a big girl!! (same as Mom)

    I haven’t been able to stock pile hardly at all because she keeps outgrowing the diapers so fast. I hope she slows down eventually or we’ll end up in Depends.

  23. Laura says:

    My son was born at 8 1/2 lbs and never wore newborn size diapers. He was super skinny but really long, and was always at the 90th percentile. He blew through 1’s, 2’s and 3’s real fast but was in size 4’s for EVER! Like at least a year and a half.

  24. Tiffany Becker says:

    This is a great guideline but it is so far off on my baby!!! We were in newborn diapers for the first 2 and a half months. we were in size 1 till 6 1/2 months and now we are in size 2 at 7 months… If you have a small baby or tall and skinny baby you will want to make sure you have the smaller ones as the bigger ones just dont fit right and have leaks…

  25. DebbyeS says:

    New mom here! I loved having a stockpile of diapers when my daughter was born.
    This has been my experience:
    I registered for and received lots of diapers. The stores (including Target, Wal-Mart and Publix) have given me no trouble exchanging diapers for the next size up even if I have no receipt (as long as it’s a package size that they carry).
    I developed brand preferences even though I had sworn that I wouldn’t! I have tried Pampers (Baby Dry and Swaddlers), Huggies, Luvs, and Up&Up. The Huggies leaked about 75% of the time and the Up&Up leaked about 25% of the time. Pampers Swaddlers have become my favorites with Luvs being a close second (and much more economical choice). Thankfully, I had a friend that had a little boy about a week after I had my daughter, and Huggies became her preferred brand. We just did a diaper exchange (Pampers for Huggies).
    Also, I was not able to keep my daughter in the diapers until the max size. At about 7 1/2 lbs. the newborn diapers were uncomfortably snug. When she was was 12 1/2 lbs. we had to move up to size 2 even though size 1 was supposedly up to 14 lbs. They just wouldn’t hold the messes!
    So far our diaper usage has been as follows:
    Newborn: approx. 100 diapers (10 days)
    Size 1: approx. 600 diapers (a little over 2 months)
    Size 2: still in them at 3 1/2 months old. approx. 250 used so far and her current rate of growth makes me think we will use about 250 more before she needs to move up to size 3.
    So get to stockpiling! Get plenty of Newborn, Size 1, and Size 2. Exchange what you don’t need!

  26. Ashley says:

    I guess my kids are just really big for their ages. My youngest daughter, born May 5th, 2014 is about to outgrow size 4. She has pretty much worn the size equal to her age, meaning she wore size 1 when she was 1 month, size 2 when she was 2 months, 3 at 3 months etc..

  27. Pauline says:

    I’v been based mostly in Thailand, running a blog about journey and food since
    2009, but I had never had a chance to go to Koh Samui before.

  28. cindy says:

    How do you exchange diapers? They’ve never let me because they say the box has been opened etc.

  29. Becky says:

    I work in a daycare with 12-24 month old. The average child starts at 12 months at size 3 but spend most of those next 12 months in size 4 and 5.

  30. Angelica P says:

    So my son was born only 2 weeks early but was born little. He was 5lbs 3 oz. He actually fit into Premies until he was about 1 month old and then switched to size 1. He was in size 1 until he was about 3 months and then went up to size 2. at 7 months we finally switched to a size 3 because although he is still skinny, he is a very tall boy. He is now 10 months and is just over 17lbs but is 29 inches tall and still has plenty of room in size 3. I think this is the size he will stay in the longest but I know with his height we might have to size up soon because when he has his blow outs, we have leakage in the back. Like others said you can stock pile on diapers and just exchange them if they grow out of them. I have never had an issue with exchanging diapers. The stores that are the best (as long as they carry the diaper count) with no questions asked is Target, Walmart, and Costco.

  31. Trish says:

    I had about 40 girls at my baby shower and had a diaper raffle with very nice prizes. At the same time, my husband had a beer and diaper party, for the guys (he only had about 15 guys there)where food and beer was provided. For the raffle I asked for NO newborn diapers. Our baby girl is now 6 1/2 months and we have NEVER bought diapers!