How many sleep sacks should I get?

Quick Answer

The recommended number of sleep sacks to have on hand is 3-5. This allows you to have a sleep sack available as others are in the wash, ensures you have backups if any get stained or damaged, and provides options for different tog ratings based on room temperature. Most babies use sleep sacks for the first 2 years of life, so stocking up on multiples ensures you’ll have what you need.

How Many Sleep Sacks Do You Need Per Baby?

When it comes to buying sleep sacks for your baby, most experts recommend having at least 3-5 on hand. Here are some of the main reasons why having multiple sleep sacks is useful:

Allows for Rotation While Washing

Babies often need their sleep sacks washed frequently, sometimes even daily. Having only 1 or 2 sleep sacks makes it difficult to ensure you always have a clean one ready. With 3-5 sacks in rotation, you’ll have extras available when others are in the laundry.

Provides Backups in Case of Damage

It’s inevitable that some sleep sacks will get stained from leaks, spit up, or blow outs. Keeping extras on hand means you won’t be left without something for your baby to sleep in if their favorite sack gets damaged.

Accommodates Changing Weather/Temperatures

Sleep sacks come in different warmth ratings based on their tog value. It’s useful to have both lightweight and warmer options to suit fluctuating temperatures. A few different tog ratings in your selection of sacks makes it easy to adjust as needed.

Allows for Convenience of Multiples

When you have more than one sack available, it’s easier to keep them stationed around the house where you’ll need them – like in the nursery, living room, etc. This prevents late night scrambling to find where you last left the sleep sack.

Provides Options for When One Gets Outgrown

Babies grow quickly, and it’s common for them to outgrow a particular sleep sack size before the others get worn out. Having multiple options ensures you’ll still have a properly fitting sack while the outgrown one gets replaced.

What Tog Options Do I Need?

Sleep sacks are designed to provide different levels of warmth based on their tog rating (a measurement of thermal insulation). Here are some recommendations on which tog ratings to have for babies:

0.5 Tog

A 0.5 tog sleep sack is very lightweight and breathable. It can be used in warmer weather over just a vest or onesie, or in heated rooms year round. This is the lowest insulation option.

1.0 Tog

A 1.0 tog sack provides light warmth, and is ideal for most nursery temperatures around 20°C (68°F). These are usually suitable under footed pajamas for a good comfort level.

2.5 Tog

Once temperatures start dropping below 20°C, a 2.5 tog sleep sack helps keep your baby cozy and warm. These are a great choice for cooler weather or air conditioned rooms.

3.5+ Tog

Higher tog ratings like 3.5+ provide extra insulation for cold weather and nights. These help babies stay warm and comfy even when the mercury dips. Useful for winter or naturally chilly rooms.

What Fabrics Are Best?

Sleep sacks come in a range of fabric types. Here are some top options:


100% cotton sacks are lightweight, breathable, and absorbent. Cotton is a natural fiber that helps regulate temperature. It’s soft against baby’s skin but requires more frequent washing.


Bamboo fabric is soft, hypoallergenic, and durable. It’s breathable like cotton but often requires less frequent washing. Sustainably sourced bamboo is an eco-friendly choice.


Microfleece sacks provide insulation and warmth without being overly bulky. Many parents like the soft, plush feel against their baby’s skin. Fleece repels liquid so avoids absorbing odors.


Lightweight muslin cotton is very breathable for warmer weather. It’s a versatile fabric that can be used year round for comfort and temperature control. Muslin gets softer over time.

Merino Wool

Merino wool sleep sacks help regulate body temperature. The natural fibers keep baby warm in winter but cool in summer. Merino resists odors for less frequent washing.

What Closures Should I Look For?

Sleep sacks secure around baby in a few different ways. Here are some closure types to consider:


A zipper front makes getting baby in and out of the sack simple and efficient. Zippers should run from bottom to chin for safety and comfort. They allow for easy diaper changes.

Overlap/Envelope Neck

Overlap closures have one fabric panel that folds over the other at the neckline. Often secured with snaps or buttons, this style makes neck openings adjustable.

Shoulder Snap Closure

Snaps across the shoulders keep the sack closed around the neck. This prevents the sack from riding up over baby’s face and is easier to re-snap for night time diaper changes.

Zip + Shoulder Snaps

For extra security, some sacks combine zipper fronts with additional shoulder snaps. This hybrid provides both the convenience of a zipper and the adjustability of snaps.

What Safety Features Should Sleep Sacks Have?

A few key safety features to look for include:

Arm Restriction Design

Restricted arm sleeves prevent dangerous loose fabric around baby’s face and reduce the risk of rolling during sleep. The sack should allow some arm mobility but contain loose material.

Neck/Chin Guard

A high neckline or chin guard keeps the top of the sack from riding up near baby’s face. This prevents any fabric from obstructing breathing.

Non-Slip Foot Soles

Grips on the feet help keep babies from sliding down in the sack, which could lead to the face covering. Soles provide traction inside the crib/bassinet.

Chest Clips

Some sacks have additional chest clips that attach to D-rings on the front panel. These help hold the sack in place for improved safety and positioning.

What Size Sleep Sacks Do I Need?

Sleep sack sizes correspond to your baby’s height and weight measurements:

Newborn Size

For babies up to 3-6 months old and weighing 8-13 lbs, with a height of 19-25 in. These have room for babies to kick inside.

Small Size

Fits babies around 6-12 months old weighing 13-20 lbs and measuring 25-29 in tall. As baby grows, this size ensures room to move.

Medium Size

Appropriate for babies from 12-18 months old, weighing 20-26 lbs and 29-33 in in height. Provides comfort as mobility increases.

Large Size

For toddlers around 18-36 months old, weighing 26-37 lbs with a height of 33-38 in. Accommodates active sleepers.

How Many Sleep Sacks Will I Need Over Time?

Most babies use sleep sacks from newborn through toddlerhood, spanning about 2 years. Here’s an estimate of how many you may go through:

  • Newborn size: 2-3 sacks
  • Small size: 3-4 sacks
  • Medium size: 3-4 sacks
  • Large size: 2-3 sacks

So over the course of use, you can estimate needing 10-14 sleep sacks total per child. Buying them incrementally as baby grows allows reassessment of needs and budgeting.

Tips for Choosing and Using Sleep Sacks

Here are some additional pointers on selecting and using sleep sacks:

  • Look for breathable fabrics like cotton or bamboo to prevent overheating
  • Check that neck openings don’t gap and provide chin coverage
  • Buy according to room temperature and adjust tog rating as seasons change
  • Machine wash gentle cycle and tumble dry low to maximize lifespan
  • Have at least 1 sack per size as baby grows to ensure good fit
  • Keep sacks stationed around home for easy access when needed
  • Replace any damaged, worn out, or ill-fitting sacks right away
  • Choose trusted brands that follow safe sleep guidelines
  • Buy extras so you always have a backup ready when others are washing

The Bottom Line

Having 3-5 sleep sacks on hand for each size range as your baby grows is ideal. This provides enough to rotate through laundering, replace if damaged, adjust warmth if needed, and keeps spares handy around the house. Aim for 10-14 total over the first 2 years for convenience and safety. Investing in multiples of this important nursery gear makes for peaceful nights!

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