ScienceBasedKids.com may earn a commission from affiliate links in this review. Our ratings are never influenced by affiliate relationships. Read our full methodology.
There’s a reason Mega Bloks First Builders show up on nearly every “best toys for 1-year-olds” list ever published. They work. The blocks are big enough that a 12-month-old can grip them, the studs connect with minimal force, the disconnection requires enough effort to be satisfying but not frustrating, and the whole set comes in a bag for $20. There’s nothing revolutionary here — but sometimes the best toy is the one that nails the fundamentals.
We tested the 80-piece Big Building Bag across four households with children ages 11 months to 5 years over six weeks.
Product Overview
The Mega Bloks First Builders Big Building Bag ($20) contains:
- 80 building blocks in 10 bright colors (red, blue, green, yellow, orange, purple, pink, white, teal, lime)
- Block sizes: Mix of standard (1×1, 1×2, 2×2) and some specialty shapes
- Storage bag: Zippered PVC bag with handle for storage and transport
- Compatibility: Works with all Mega Bloks First Builders products
The blocks are approximately twice the size of standard LEGO bricks and comparable in size to LEGO DUPLO. The connection mechanism uses large studs on top and hollow receivers on the bottom — the same principle as LEGO, scaled up for toddler hands.
Our Evaluation
Build Quality: 7/10
Mega Bloks are good but not exceptional in build quality. The plastic is durable and the colors are vivid. The stud connections are firm — blocks click together satisfyingly and hold through moderate handling. However, compared to LEGO DUPLO, there’s a noticeable difference in manufacturing precision. Some blocks in our sets had slightly inconsistent stud heights, leading to occasional loose connections. This doesn’t significantly impact play but is perceptible when compared directly to DUPLO.
The storage bag is functional but won’t last forever. The PVC material is thin, and the zipper is the weakest component. Expect the bag to serve as storage for 12-18 months before it needs replacement.
Play Value: 8/10
Mega Bloks excel at the core building experience. The oversized studs make connection genuinely easy for 12-month-old hands — this is the product’s primary advantage over DUPLO, which requires slightly more precision. Towers, walls, enclosures, vehicles, and abstract structures are all achievable depending on the child’s age and motor development.
80 blocks is a generous quantity. Children in our testing built structures using 40-60 blocks at a time, leaving enough remaining blocks to feel abundant rather than constrained. The variety of block sizes supports both simple stacking (1×1 blocks) and more complex building (2×2 base blocks supporting 1×2 walls).
Age Appropriateness: 9/10
The 1-5 age range is one of the widest effective ranges of any toy we’ve reviewed. One-year-olds can genuinely stack and connect blocks. Five-year-olds build complex structures with doors, roofs, and interior rooms. The play naturally progresses from simple stacking to intentional construction as motor skills and spatial reasoning develop.
Durability: 8/10
The blocks themselves are nearly indestructible. Drop them, throw them, step on them — they survive. Colors don’t fade with washing (and these blocks will need washing). The stud connections don’t degrade with use over the testing period. The storage bag, as noted, is the durability weak point.
Value for Money: 9/10
At $0.25 per block, Mega Bloks First Builders offer the best price-per-piece ratio of any quality building block we’ve tested. LEGO DUPLO runs approximately $0.50-0.75 per brick. The lower price point makes it easy to buy additional sets for volume — and volume matters in block play.
The Evidence
Block play and spatial reasoning. Verdine et al. (2014) demonstrated that spatial assembly performance with blocks in preschoolers predicts later mathematical skills.1 Block play is one of the most consistently supported developmental activities in the early childhood research literature.
Construction play and executive function. Richardson et al. (2014) found that children who engaged more frequently in block play showed stronger spatial language and spatial skills.2 The open-ended nature of block construction requires planning, sequencing, and problem-solving — core executive function skills.
The importance of block quantity. An underappreciated factor: Christakis et al. (2007) found that the number of blocks available significantly influenced the quality and duration of play episodes.3 The 80-block quantity in this set provides sufficient material for sustained, complex play.
Safety Notes
Mega Bloks First Builders meet ASTM F963, EN-71, and CPSIA standards. The blocks are specifically designed to be too large for choking hazard classification. The blocks are BPA-free and phthalate-free. No active CPSC recalls.
The blocks are large enough to cause discomfort when stepped on — barefoot parents will relate — but not heavy enough to cause injury when thrown.
The Verdict
Mega Bloks First Builders 80-piece set is the workhorse of toddler construction play. It’s not the most premium option (DUPLO holds that title), but it hits the essential targets: age-appropriate connection difficulty, sufficient block quantity, bright colors, reasonable durability, and an exceptional price point. The evidence base for block play is among the strongest in the toy research literature, and these blocks deliver that play experience starting at 12 months.
Product Rating: 8/10 — Excellent age range, generous quantity, outstanding value. Manufacturing precision and storage bag quality prevent a higher score.
Evidence Rating: Moderate — Block play is one of the most well-researched play activities. Strong evidence for spatial reasoning and executive function benefits.
Who Should Buy This
- Parents of 12-18 month olds ready for their first building blocks
- Families looking for maximum building material per dollar
- Daycare programs and playgroups needing durable, washable blocks
- Gift-givers seeking a universally appropriate toddler gift under $25
Who Should Skip This
- Families already invested in the LEGO DUPLO ecosystem
- Parents who prioritize premium build quality over value
- Children over 4 who are ready for standard LEGO bricks
This review reflects our independent evaluation. ScienceBasedKids.com purchased this product at retail price. We may earn a commission if you purchase through our links, which helps fund our research. This never influences our ratings.
Footnotes
-
Verdine, B. N., Golinkoff, R. M., Hirsh-Pasek, K., Newcombe, N. S., Filipowicz, A. T., & Chang, A. (2014). “Deconstructing building blocks: Preschoolers’ spatial assembly performance relates to early mathematical skills.” Child Development, 85(3), 1062-1076. ↩
-
Richardson, M., Hunt, T. E., & Richardson, C. (2014). “Children’s construction task performance and spatial ability: Controlling task complexity and predicting mathematics performance.” Perceptual and Motor Skills, 119(3), 741-757. ↩
-
Christakis, D. A., Zimmerman, F. J., & Garrison, M. M. (2007). “Effect of block play on language acquisition and attention in toddlers.” Archives of Pediatrics & Adolescent Medicine, 161(10), 967-971. ↩
Recommended Accessories
Affiliate links
Mega Bloks First Builders Big Building Bag (80-piece, Pink)
“Double your supply in a different color palette. More blocks means bigger builds.”
Mega Bloks First Builders ABC Musical Train
“Compatible base with letter blocks. Adds themed building.”
LEGO DUPLO Classic Brick Box
“Premium alternative. Better build quality and brand ecosystem, higher price.”
Sterilite 66-Quart Clear Storage Container
“When the storage bag wears out, this container holds 160+ blocks.”
