Choosing the right size bike for your child can feel overwhelming. Unlike adult bikes sized by frame, kids’ bikes are sized by wheel diameter. Even then, dimensions like standover height and seatpost adjustability vary significantly between brands. And let’s face it, a “6-year-old” can range from petite to tall, making a one-size-fits-all approach impossible.
Don’t worry! Finding the perfect bike size for your 6 year old doesn’t have to be a struggle. We’ve helped countless parents navigate this process, and these three key tips will guide you to the right bike the first time.
1) Understanding Kids’ Bike Wheel Sizes
Kids’ bikes are categorized by their wheel size, measured in inches. The smallest pedal bikes start at 12-inch wheels, progressing up to 24-inch wheels. Once your child is ready for 26-inch wheels, they typically transition to adult-sized bikes, though some manufacturers offer smaller “youth” 26-inch models.
Balance bikes, designed for toddlers, begin with even smaller wheels, often 12 or 14 inches, and sometimes as small as 10 inches.
The first step in determining the right bike size for your 6 year old is to identify the probable wheel size they need. We say “probable” because age-based recommendations are based on average heights. If your child is significantly shorter or taller than average, they might need a smaller or larger bike than suggested. Think of the following chart as a starting point.
Kids Bike Size Chart: A Starting Point
Remember, this chart is a general guideline to estimate the appropriate wheel size for your child. Always proceed with the subsequent steps for accurate sizing!
| Wheel size | Age | Height | Inseam |
|---|---|---|---|
| 12” | 2-3 | 2’10”-3’4” | 14-17” / 35-42 cm |
| 14” | 3-4 | 3’1”-3’7” | 16-20” / 40-50 cm |
| 16” | 4-5 | 3’7”-4’0” | 18-22” / 45-55 cm |
| 18” | 5-6 | 3’9”-4’3” | 20-24” / 50-60 cm |
| 20” | 5-8 | 4’0”-4’5” | 22-25” / 55-63 cm |
| 24” | 7-11 | 4’5”-4’9” | 24-28” / 60-72 cm |
For a 6 year old, this chart suggests a bike with 18-inch or 20-inch wheels might be suitable. However, to pinpoint the best fit, we need to move beyond age and look at your child’s measurements.
2) Accurately Measure Your 6 Year Old: Height and Inseam are Key
The next crucial step is to measure your child’s height and inseam. Do not skip this step or rely on guesswork! Accurate measurements are essential for selecting the right bike size.
If the bike is a surprise gift, you can discreetly ask the parents to measure the child, perhaps under the guise of needing measurements for clothing.
You’ll need measurements in inches (or convert centimeters to inches).
To measure inseam, have your child stand with their back against a wall, feet slightly apart. Place a book between their legs, spine upwards, and have them hold it snugly against their crotch. Mark the wall at the top of the book’s spine with a pencil. Measure the distance from the floor to the pencil mark – this is the inseam. Measure their height from head to toe as well.
Record these measurements – they are vital for the next step.
3) Check Bike Specifications: Standover Height and Seatpost Height
Just because a bike has 18-inch wheels (suggested for a 6 year old) doesn’t guarantee it will fit your child. Bike geometry varies significantly. Different models have different standover heights and minimum/maximum seatpost heights. Your goal is to find a bike that offers the best fit for your 6 year old.
While not all manufacturers publish standover height, it’s a crucial specification to look for. Standover height is the height of the bike’s top tube at the point where your child would straddle the bike while standing. Your child’s inseam must be at least as long as the bike’s standover height. Ideally, there should be a little clearance for comfortable maneuvering.
Your 6 year old needs to comfortably stand over the bike’s top tube.
Another critical specification is the minimum seatpost height. How this relates to your child’s inseam depends on their cycling experience.
For a first pedal bike (or still using training wheels), the minimum seatpost height should be equal to or no more than 1 inch greater than your child’s inseam. This allows them to place their feet flat on the ground for stability and confidence as they learn to pedal and balance.
For a 6 year old transitioning from a balance bike or just starting on pedals, prioritize a minimum seatpost height very close to their inseam.
For a balance bike or first pedal bike, your 6 year old should be able to place their feet flat on the ground while seated.
If your 6 year old is already a confident pedaler without training wheels, you have slightly more flexibility. You can consider a minimum seatpost height that is 1-3 inches taller than their inseam. This allows for efficient pedaling with a slight toe-reach to the ground for stops.
This confident rider, possibly a slightly older 6 year old or very skilled one, is comfortable with just toe-reach.
Never choose a bike with a minimum seatpost height more than 3 inches greater than your child’s inseam. They will struggle to reach the ground, pedal effectively, and risk injury.
Where to find these specifications? The best source is the manufacturer’s website. Reputable brands will provide detailed bike specs. If standover height or seatpost ranges are not listed, it’s wise to consider other brands that prioritize this information.
Some manufacturers even offer online tools to help you size your child. The Woom Bike Quiz or the Guardian Bikes RideSizer are excellent examples that simplify the selection process.
Woom bikes size chart simplifies bike selection for your 6 year old.
Another helpful resource is our comparison charts. We compile lists of top kids’ bikes in each size category, including key specifications like standover height and seatpost ranges, making it easy to compare models and find the perfect fit for your 6 year old.
Balance Bike Guides & Comparison Charts: [Link to Balance Bike Charts (example)]
Pedal Bike Guides & Comparison Charts: [Link to Pedal Bike Charts (example)]
What if Your 6 Year Old is Between Bike Sizes?
It’s common for children, especially 6 year olds, to fall between recommended sizes. Parents often worry about choosing a bike that will be outgrown too quickly. This is a valid concern.
If your child is very close to the upper end of the recommended height/inseam range for a particular bike size, sizing up is often the better choice, particularly if they are already comfortable pedaling.
Consider your 6 year old’s confidence and athleticism. Can they handle a slightly larger, potentially heavier bike? Will they be comfortable with toe-reach, or might it be intimidating?
If your child is new to cycling or less confident, sticking with the smaller size is generally recommended, even if they might outgrow it sooner. In this case, explore options like used bikes or borrowing from friends to bridge the gap until they are ready for the next size. You can then invest in a higher-end bike when they are firmly in the next size range.
A Note on BMX Bikes for 6 Year Olds
BMX bike sizing differs from standard kids’ bikes. There are two main types: freestyle/street BMX (for skateparks) and racing BMX (for tracks).
For freestyle/street BMX, generally choose a wheel size smaller than you would for a regular kids’ bike. For instance, if your 6 year old would typically ride an 18-inch bike, a 16-inch BMX might be more appropriate.
Learn More About BMX Sizing: [Link to BMX Sizing Guide (example)]
For race BMX bikes, the wheel size is consistently 20 inches, even for younger riders. Frame size is the variable that changes as your child grows. Here’s a race BMX size chart:
| Size | Age | Height |
|---|---|---|
| Micro Mini | Under 5 | 3’6″-4’0″ |
| Mini | 5-7 | 4′-4’4″ |
| Junior | 7-9 | 4’3-4’7″ |
| Expert | 9-11 | 4’6″-5’5″ |
| Expert XL | 10-13 | 5’3-5’7″ |
Bike Size is Just the First Step
While crucial, bike size is only the initial consideration. Once you’ve determined the right size bike for your 6 year old, other factors become important: bike weight (especially for kids), frame geometry, brakes, tires, and whether training wheels are needed.
For in-depth guidance on these aspects, refer to our comprehensive Guide To The Best Kids Bikes & How To Choose! [Link to Kids Bike Buying Guide]
About Us
We are the Rascals: Kristen (mom), Blair (dad), and Parker (kiddo). Rascal Rides was born from our desire to continue biking as a family after Parker arrived. Sharing our experiences and learnings, we’ve tested hundreds of kids’ bikes, helmets, trailers, and more over the years.
Kristen is a certified USA Cycling coach, passionate about sharing her love for biking with families. Blair is our resident bike geek, mechanic, and mountain bike enthusiast. Parker is our invaluable tester and inspiration.
Say hello if you spot us on the trails!
