11 January 2013

OS diaper size comparison

OS diaper size comparison
Comparing crotch width of various OS diapers
With so many one-size diapers available, not all of them will fit your baby equally well. One-size diapers come in a wide variety of sizes which makes different brands suitable for different babies/toddlers, depending on their build - big waist/small waist, long rise/short rise, skinny legs/chubby legs. 

I decided to do a size comparison between the diapers I have to give you a better idea of which one will fit your baby the best. 

The one-size diapers I compared are the following: Bam+Boo Ai2/pocket diaper, Imagine pocket diaper, Imagine Bamboo AIO, Cherub Tree pocket diaper, Cherub Tree AIO diaper, Fancypants pocket diaper, Bumgenius 3.0 pocket diaper, Alva* pocket diaper (regular), Alva* pocket diaper (slimfit), Mother Nature AIO diaper.

(* Alva diapers are available in SA under the label Snugglybum)

OS diaper size comparison
Adjusted to their smallest sizes, from big to small. Left to right, top to bottom: Alva, Imagine pocket, Bam+Boo, Mother Nature AIO, Bumgenius 3.0, Cherub Tree pocket, Cherub Tree AIO, Alva (slimfit), Imagine Bamboo AIO, Fancypants
First I sized all the diapers down to their smallest waist and rise settings to see which would fit a small baby the best.

Smallest overall diaper - Fancypants with Imagine AIO a close second
Smallest waist - Fancypants with Cherub Tree pocket a close second (mn AIO or imagine AIO on biggest setting)
Shortest rise - Imagine AIO
Narrowest crotch - Cherub Tree pocket & AIO, as well as Alva (slimfit)
Smallest leg openings - Fancypants, with Imagine AIO & Cherub Tree AIO a close second. (mn AIO on large setting)
Least likely to fit a newborn/small baby - Alva (regular) and Imagine pocket

OS diaper size comparison
Smallest setting: biggest (Alva regular) vs smallest (fancypants)

Note - The average one-size diaper will generally only start fitting once your baby reaches 5.5 kg.  
OS diaper size comparison
Adjusted to their biggest sizes, from big to small. Left to right, top to bottom: Bam+Boo, Imagine pocket, Alva, Fancypants, Bumgenius 3.0, Cherub Tree pocket, Cherub Tree AIO, Alva (slimfit), Mother Nature AIO, Imagine Bamboo AIO

Then I sized them all up to their biggest waist and rise settings to assess how they would fit a big toddler. 

Biggest overall diaper - Bam+Boo (Alva (regular) or Imagine pocket (on small setting)).
Largest waist - Bam+Boo 
Longest rise - Bam+Boo (Alva on small setting) 
Widest crotch - Bam+Boo 
Biggest leg openings - Bam+Boo with Fancypants a close second. (Alva (on small setting))
Least likely to fit until potty training age - Imagine AIO and Mother Nature AIO

OS diaper size comparison
Biggest setting: smallest(Imagine AIO) vs biggest (Bam+Boo)
A few other observations which affect fit:

Stretchiest - Fancypants, Imagine pocket
Least stretchy - Bam+Boo, Alva
Trimmest - Bumgenius 3.0 (using newborn insert only), Cherub Tree pocket when using the one-size insert
Bulkiest - Mother Nature AIO, Bam+Boo

OS diaper size comparison
Comparing waist sizes - adjusted to smallest setting
I hope this gives you a better idea on the size differences between the different brands and helps you in figuring out which diaper will fit your baby the best. As always though, my advice would be to buy one of each brand and try them on your baby first before committing to buying a whole stash of one specific brand - you just never know what will work on your baby until you try it!


  1. Soon you can add a Fuzzibunz nappy to this comparison! :)

  2. Hi Marisa,

    I'm expecting my second kid in August and we've decided to go the reusable route. Just wondering on the actual usability on the diapers. I was set on getting myself a fancypants kit, but then read a review that they sometimes leak. Can you perhaps shed some light on which ones are most effective please?

    Thanks a bunch!

    1. Leaks are either due to fit (leg gaps) or absorbency (ie output is more than the nappy can handle). Both are easy to solve - either adjust fit or add more absorbency (ie extra inserts). Effectiveness will depend on your baby's output, some babies are light wetters, while others are medium or heavy wetters.


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