Millie Moon Diaper Size Guide: Premium Fit at a Value Price

Millie Moon arrived as a Target exclusive and quickly built a following for a soft, premium-feeling diaper at a surprisingly low price. The plush build only pays off with the right size, and because the line skips the newborn stage, it pays to plan your start point.

This guide covers the full Millie Moon range, what to expect at each size, how much to buy, and how its sizing compares to other brands. Start with the finder above to match your baby's weight.

Understanding Millie Moon sizes

The everyday Luxury line covers Size 1 through Size 6 using the standard US weight ranges, so sizes match other brands and you go by weight. There is no Newborn size, so the early weeks need another diaper, and the line stops at Size 6.

The ranges overlap, so a baby can sit between two sizes; let the leg fit break the tie, remembering Millie Moon is cut on the generous side. The Overnight line is narrower still, covering Size 4 through Size 6 for older babies sleeping longer, so younger babies wear the Luxury diaper around the clock.

Millie Moon size chart

What to expect at each size

Millie Moon does not make a Newborn size, so the first weeks are covered by another diaper. Once your baby reaches roughly eight pounds and Size 1, you can move onto Millie Moon, which is around when many parents discover it by word of mouth.

Size 2 and Size 3 carry most of the first year, with Size 3 the long-running size. The soft, generous cut earns its fans through this stretch, and Size 3 is the one to buy in bulk.

From Size 4 to Size 6, the Overnight line becomes available for heavy night wetters while the Luxury diaper continues by day. Both stop at Size 6, so a larger toddler will need a Size 7 elsewhere for the final stretch.

Every Millie Moon diaper, reviewed

Luxury Diapers

Daytime

4.4$0.32/diaper

Luxurious comfort and gentle on delicate skin for ultimate protection.

Read the Luxury Diapers review

Overnight Diapers

Overnight

3.9$0.51/diaper

Ultra-absorbent, gentle on skin, feather soft overnight diaper for restful nights.

Read the Overnight Diapers review

Which Millie Moon diaper fits which size

Luxury is the everyday default from Size 1 to Size 6. From Size 4 up, the Overnight line adds absorbency for nights, also topping out at Size 6. Plan a separate Newborn diaper for the first weeks. The grid above shows the Size 1 start, the Size 4 overnight start, and the Size 6 finish for both lines.

What Millie Moon diapers cost

This is Millie Moon's headline: a premium-feeling diaper at one of the lower per-diaper prices in its class. The estimator above shows the yearly math that has made it a word-of-mouth favorite among Target shoppers. The Overnight line costs more per diaper, as overnight diapers do, but the everyday value is the brand's calling card.

How many Millie Moon diapers to buy by size

You skip the newborn stockpile with Millie Moon, since it starts at Size 1. Begin modestly at Size 1, buy a little more at Size 2, then stock up at Size 3, the longest-worn size and where the value lands hardest. From Size 4 to Size 6, reorder steadily and add the Overnight line in modest quantities for nights. Millie Moon is Target-exclusive and occasionally sells out during demand spikes, so when you find your main size in stock, it is worth grabbing a box plus a reserve pack of the next size up.

Millie Moon sizing tips, from newborn to potty training

Millie Moon starts at Size 1, so your first sizing decision is really when to start. Use another diaper for the newborn weeks and move to Millie Moon around eight pounds, when your baby reaches Size 1; this is often exactly when parents hear about it by word of mouth and want to try the plush feel. Weigh your baby every couple of weeks through the early months and go by weight, remembering the line is cut on the generous side, so if your baby is between sizes and lean, the smaller size may seal better.

Use the overlap and the Overnight line for nights. From Size 4, run the everyday Luxury diaper by day and the Overnight diaper at night for extra capacity; before Size 4, simply size up a Luxury diaper for sleep if mornings are wet. Both lines stop at Size 6, so plan a Size 7 alternative before a larger toddler outgrows the range.

Buy with Target's stock in mind. Millie Moon is a Target exclusive and can sell out during demand spikes, so when your main size, usually Size 3, is in stock, grab a box and a smaller pack of the next size up as a buffer. Keep early sizes lean since they pass quickly, and because the everyday line is such good value, this is one premium-feeling diaper where bulk-buying at Size 3 genuinely pays off. Use the two-finger waistband test and a clean leg seal to judge when to move up, allowing for the diaper's generous cut.

Getting the fit right

Millie Moon runs true to size with a soft, generously cut fit that parents often praise for comfort. Track your baby's weight and step up at the usual signs of tabs at the center, a clean leg seal, and no marks. The checker above helps you decide. Remember the line starts at Size 1, so newborns need an alternative for the early weeks.

Switching to or from Millie Moon

Switching to Millie Moon is easy once your baby is in Size 1, since it uses the standard weight chart and your size number carries over. Two things to plan around: the missing Newborn size, which means starting on another brand, and the Size 6 ceiling, which means a Size 7 alternative for a larger toddler. Because it is Target-exclusive and popular, keep an eye on stock and judge the fit by weight and the usual signs.

Common Millie Moon sizing mistakes to avoid

The first Millie Moon mistake is expecting a Newborn size. It starts at Size 1, so plan another diaper for the early weeks and switch around eight pounds; parents who buy Millie Moon for a newborn are often surprised there is no smaller option. The second is ignoring the generous cut. Millie Moon runs soft and roomy, so a baby between sizes, especially a lean one, often seals better in the smaller size, and defaulting to the larger one can invite leg leaks.

A third pitfall is the Size 6 ceiling on both lines, which means a larger toddler needs a Size 7 alternative ready in advance. A fourth is being caught out by stock: Millie Moon is Target-exclusive and sells out during demand spikes, so when your main size is available, buy a box and a buffer pack of the next size up rather than assuming it will be there next week. Do not overstock the small sizes, which pass quickly, and because the everyday line is such good value, do put your bulk buying into Size 3. As always, weigh your baby and go by weight rather than age, moving up only when tabs no longer reach the center or the leg seal starts to fail.

How Millie Moon compares

See how the Luxury diaper compares with the alternatives parents most often weigh it against.

The bottom line

Millie Moon is the value-premium sweet spot for Target shoppers: a plush diaper that does not cost like one, from Size 1 to Size 6. Match the size, buy your bulk at Size 3, and it consistently overdelivers.

Comparing brands? Browse our other diaper size guides to see how the fit and sizing stack up.