One of the most common questions new parents ask is "How long can my baby use the bassinet?" The answer isn't simply a number—it depends on a combination of weight limits, age guidelines, and developmental milestones. Understanding these factors helps you know when it's time to transition to a cot and ensures your baby stays safe throughout their bassinet days.
Weight Limits: The Numbers
Every bassinet has a manufacturer-specified weight limit, typically ranging from 7 to 10 kilograms, with 9 kilograms being the most common limit. This weight restriction exists because the bassinet's structural design, mattress support, and stability are engineered for a specific load.
Here's what typical weight limits look like across popular bassinet types:
- Standard bassinets: 8-10 kg
- Travel/portable bassinets: 7-9 kg
- Bedside bassinets: 9-10 kg
- Smart bassinets (like SNOO): 11-13 kg
- Moses baskets: 6-8 kg
Always check your specific bassinet's documentation for its exact weight limit. Using a bassinet beyond its weight capacity can cause structural failure, creating serious safety risks.
Weight limits are maximum capacities, not targets. You should transition your baby before they reach the limit, not after. Many parents begin the transition when baby is 500g-1kg below the maximum weight.
Age Guidelines: A Rough Timeframe
Most bassinets are designed for use from birth until around four to six months of age. However, age is a general guideline rather than a firm rule. A small baby might comfortably use a bassinet for six months, while a larger baby might outgrow it at three months.
The age guidelines exist because they roughly correspond to two factors: weight gain and motor development. The average Australian baby doubles their birth weight by around four months, which often brings them close to bassinet weight limits. Additionally, motor development milestones that make bassinets unsafe typically emerge between three and six months.
Developmental Milestones: The Critical Factor
Perhaps more important than weight or age are developmental milestones. Certain physical abilities make bassinets unsafe regardless of how much baby weighs or how old they are. You must transition to a cot when your baby shows any of these signs:
Rolling Over
Once a baby can roll from back to tummy (or vice versa), they need a larger, safer sleep space. The confined dimensions of a bassinet don't give a rolling baby room to manoeuvre safely. If they roll in a bassinet, they might end up against the side with restricted breathing or in a position they can't get out of.
Pushing Up on Hands and Knees
When babies start pushing up—the precursor to crawling—they can potentially push against the sides of the bassinet with enough force to tip it or could attempt to pull themselves up. This creates a fall risk even if they haven't yet learned to stand.
Sitting Up Unassisted
A baby who can sit up independently definitely needs a cot. Bassinets aren't designed to contain a sitting baby, and the risk of toppling over the side becomes significant.
The golden rule: If your baby can roll, push up, or sit, it's time to move to a cot—regardless of their weight or age.
Signs Your Baby is Outgrowing the Bassinet
Beyond the clear developmental milestones, watch for these signs that your baby is ready for a larger sleep space:
Length Issues
If your baby's head or feet are touching or nearly touching the ends of the bassinet, they need more room. A cramped baby won't sleep as comfortably and may wake more frequently.
Increased Movement During Sleep
Babies naturally move during sleep, cycling between sleep stages. If your baby seems to be constantly bumping against the sides or waking themselves by hitting the edges, they've outgrown the space.
The Bassinet Feels Unstable
As babies grow heavier and more active, you might notice the bassinet feeling less stable—more wobble, more creaking, or slight tipping when baby moves vigorously. These are signs the bassinet is being used at the edge of its design capacity.
Restless Sleep
Some babies sleep more poorly in the bassinet as they outgrow it. If your baby was sleeping well and suddenly seems uncomfortable or restless, the bassinet size might be a factor worth considering.
Tracking Your Baby's Weight
Regular weight checks help you anticipate when the transition will be needed. In Australia, you'll have scheduled visits with your child health nurse who will track your baby's weight on a growth chart. Between visits, you can:
- Weigh yourself, then weigh yourself holding baby, and calculate the difference
- Use baby scales if available at your local pharmacy or early parenting centre
- Note how clothes fit—rapid growth often means clothes becoming tight quickly
Growth happens in spurts rather than steadily, so don't be surprised if your baby seems to approach the weight limit suddenly after weeks of slow gain.
What Happens If You Exceed Limits?
Using a bassinet beyond its rated capacity isn't worth the risk. Potential consequences include:
- Structural failure: The mattress support or frame could give way
- Tipping: A heavier, more active baby can tip the bassinet, especially if they shift their weight to one side
- Mattress compression: The mattress may compress under higher weight, potentially creating an unsafe, saggy sleep surface
- Hardware stress: Joints, hinges, and locking mechanisms may fail under excess load
Don't wait until your baby has clearly outgrown the bassinet to start thinking about the cot transition. Have the cot set up and ready before you need it, so you're not rushing to assemble furniture while also managing a baby who can't safely use the bassinet.
Special Considerations
Premature Babies
Premature or low birth weight babies may be able to use bassinets longer than average since they often take time to catch up in weight. However, developmental milestones still apply—even a smaller baby who can roll needs to transition. Use your baby's developmental age (adjusted for prematurity) when thinking about motor milestones.
Larger Babies
If your baby was born large or is in higher weight percentiles, you may have a shorter window of bassinet use. Some parents of larger babies find the bassinet useful for only eight to twelve weeks. This is normal—plan accordingly and don't feel you've wasted money on a bassinet even if use time is brief. The early weeks of convenient, portable sleep are valuable regardless of duration.
Twins or Multiples
Each baby needs their own safe sleep space. For twins, this typically means two bassinets or an early transition to cots placed side by side. Never place two babies in a single bassinet designed for one—the weight limit and space constraints make this unsafe.
Making the Transition Easier
When you determine it's time to move from bassinet to cot, gradual transition can help. Some approaches include:
- Starting with daytime naps in the cot while keeping night sleep in the bassinet (if still safe)
- Placing the cot in your room initially before moving to the nursery
- Using familiar bedding (same sheets, same sleep bag) in the new sleep space
- Maintaining the same sleep routines and environmental conditions
For detailed strategies, see our guide on transitioning from bassinet to crib.
The Bottom Line
While weight limits and age guidelines provide useful benchmarks, the most important factor in determining when to stop using a bassinet is your individual baby's development. Watch for rolling, pushing up, or sitting; monitor how comfortable your baby seems in the space; and always err on the side of caution. When in doubt, it's time to move to the cot.
The bassinet phase is brief but precious. Knowing when it's time to transition helps you make the most of these early months while keeping your baby safe as they grow.