CrunchLabs Build Box review

CrunchLabs Build Box sends one engineering toy a month to kids aged 8 to 13, and each one is designed around a single principle. The examples CrunchLabs shows include a disc launcher that uses a flywheel, a boomerang car driven by a worm gear and a paper airplane launcher built on springs. Kids follow step-by-step instructions, play with the finished toy, then watch a video from Mark Rober that explains the physics behind it. CrunchLabs says the lessons cover projectile motion, momentum transfer, hydraulics and mechanical engineering basics. Pricing is the strongest of the engineering boxes we compared: $27.45 per box on the annual prepaid plan, which totals $329.40 with free US shipping, or $29.95 per box if you pay monthly on an annual commitment. The trade-offs are the up-front payment for the lowest price and a narrow subject range: there is no chemistry, biology or art. Families with a younger child can look at the CrunchLabs Creative Kit for ages 6 to 10, and teens can move to Hack Pack.

Who it is for

kids 8 to 13 who like building toys that launch, roll and fly

Price

$27.45 per box on the annual prepaid plan ($329.40 a year, free US shipping); $29.95 per box on annual pay monthly; $32.95 per box quarterly.

$27.45 PER BOX
Quoted from the vendor pricing page on November 12, 2026.

Key features

• A new build-it-yourself toy every month for ages 8 to 13
• Each box is built around one principle, such as a flywheel, worm gear or springs
• An educational video from Mark Rober unlocks with every box
• Annual prepaid plan costs $329.40 a year with free US shipping
• Every box enters the child in a draw for a Platinum Ticket to visit CrunchLabs

Strengths and weaknesses

• Strength: Lowest per-box price for a monthly engineering kit here at $27.45 on the annual plan
• Strength: Projects named on the page are toys kids keep playing with, such as a disc launcher and a boomerang car
• Strength: Clear path upward: Hack Pack covers robotics and coding for ages 14 and up
• Weakness: The $27.45 price requires paying $329.40 up front for 12 months
• Weakness: Quarterly billing raises the price to $32.95 per box
• Weakness: Focused on mechanical engineering and physics, with no chemistry or biology kits

Key facts

• Ages: 8 to 13
• Price: From $27.45 per box
• Delivery: Monthly
• Subjects: Engineering and physics
• Extras: Video from Mark Rober with every box

Where it ranks

CrunchLabs Build Box is No. 1 in our Best STEM Subscription Boxes verdict.