One of the most common questions we receive is:
"Which fitted diaper size should I buy?"
The answer depends on a few different factors, including your baby's size, your budget, and how important a trim fit is to you during different stages.
At Lilly & Frank, we offer four fitted diaper sizes because we know every family cloth diapers differently. Some parents want the best possible fit on a tiny newborn. Others prefer to invest in fewer diapers that last longer. Neither approach is wrong—it's simply about choosing what works best for your family.
Let's take a closer look at each size.
Newborn Fitted Diapers (6–14 lbs)
Our newborn fitted diapers are designed specifically for tiny babies.
While many one-size diapers claim to fit from birth, newborns often benefit from a diaper that's truly designed for their smaller body shape. A better fit means less bulk, easier clothing fit, and excellent containment during those early weeks.
Newborn diapers are a short-term investment, but they continue to hold value long after your baby outgrows them.
Many families:
Save them for future children
Lend them to friends or family members
Sell them in our Buy, Sell & Trade community
Repurpose the inserts as absorbency boosters in larger diapers
If you're planning to cloth diaper from birth and want the best possible fit for your newborn, this is the size we recommend. Shop Newborn Fitted Diapers →
Petite Fitted Diapers (7–30 lbs)
If you'd like to start cloth diapering from birth but don't want to invest in a separate newborn stash, our Petite Fitteds are often the perfect middle ground.
The Petite size was originally created because I found traditional one-size diapers bulky on my third child. I wanted something that would fit smaller babies beautifully while still offering plenty of room to grow.
Compared to a traditional one-size diaper, the Petite provides:
A trimmer fit
Less bulk under clothing
Better proportions for slender babies
More room to grow than a newborn diaper
Many babies can wear this size from birth all the way through potty learning, though that will depend on your child's build and growth pattern.
If your baby is on the leaner side or you prefer a trim-fitting diaper, the Petite is often a customer favorite. Shop Petite Fitted Diapers →
One Size Fitted Diapers (12–35 lbs)
Our One Size fitted diaper is designed to fit most babies through the majority of their cloth diapering journey.
This is the size many families choose when they are looking for the greatest balance between longevity and value.
Compared to the Petite, the One Size offers:
More room through the rise and waist
A fit that accommodates a wider variety of body types
Extended use as your baby grows
While it isn't typically the best fit for a newborn, it becomes an excellent everyday option once your baby reaches approximately 12 pounds.
For many families, this is the "workhorse" size of their stash. Shop One Size Fitted Diapers →
Toddler Fitted Diapers (20–60 lbs)
Our Toddler fitted diapers were created for babies and children who need more room than a traditional one-size diaper can provide.
They're perfect for:
Bigger babies
Tall babies
Toddlers
Children who potty train later
Families starting cloth diapering after infancy
Because of their generous sizing, Toddler fitteds often become the longest-lasting diapers in a family's stash.
Many families continue using them:
For overnight protection
During potty learning
As an alternative to disposable training pants
For children who still need overnight absorbency at 3 or 4 years old
If your child is already approaching the upper end of a one-size diaper—or you know they're growing quickly—the Toddler size can be an excellent investment. Shop Toddler Fitted Diapers →
Still Not Sure Which Size to Choose?
Here's a quick guide:
Choose Newborn (6–14 lbs) if:
You want the best fit on a tiny baby.
You're cloth diapering from birth.
You don't mind investing in a dedicated newborn stage.
Choose Petite (7–30 lbs) if:
You want to start from birth and minimize the number of sizes you purchase.
Your baby is slender or average build.
You prefer a trim-fitting diaper.
Choose One Size (12–35 lbs) if:
Your baby is already past the newborn stage.
You want the best balance of value and longevity.
You're building a practical everyday stash.
Choose Toddler (20–60 lbs) if:
Your baby is larger than average.
You're starting cloth diapering later.
You need a diaper that will last through potty learning and beyond.
At the end of the day, there isn't one "best" size—only the size that best fits your baby and your family's goals. Whether you're cloth diapering a tiny newborn, a chunky toddler, or anything in between, we're here to help you find the right fit.