The picks
STEM Subscription Boxes for Kids
You are buying twelve projects, not one toy. Priced that way, some of these are good and some are not.
By Sawyer V. · Published
The short answer
A subscription works if — and only if — someone will reliably sit down with the child in the week the box arrives. KiwiCo publishes a clear ladder by age: Kiwi Crate at 6-9, Tinker Crate at 9-12, Eureka at 12+. MEL Science publishes 2-3 experiments per monthly set for 10 and up, with a reusable home lab in the first shipment.
Block & Beaker earns a commission when you buy through our links, at no cost to you. It never changes a ranking, and we say so plainly when the right answer is the cheaper set, or nothing at all. Full disclosure · How we pick.
At a glance
The picks, ranked
Tap any row to jump to the full reasoning. Prices come live from Amazon where we have them and read “check price” where we don’t — never a number we cannot stand behind today.
| # | Product | Best for | Price |
|---|---|---|---|
| 1 | Best for 6 to 9 Kiwi Crate monthly subscription One hands-on STEAM project a month, pitched at exactly the age where a child can mostly do it alone. | A child who likes making things and has an adult around | |
| 2 | Best for 9 to 12 Tinker Crate monthly subscription The engineering rung: monthly builds that are machines rather than crafts. | A child who asks how things work rather than wanting to make things | |
| 3 | Best for real chemistry MEL Chemistry monthly subscription Genuine reagent chemistry monthly, with the equipment supplied once and reused. | Ten and up, in a household with a reliably free adult | |
| 4 | The alternative to a subscription NATIONAL GEOGRAPHIC Mega Science Lab One box, 45 kit experiments plus 85 household ones — available whenever someone is free rather than on the 23rd. | A household that cannot promise a free evening every month | |
| — | The one to skip 4M Crystal Growing Experiment Kit Bought as a substitute for a subscription, it delivers seven slow results and then nothing. | Not this category at all |
5 picks, including 1 we tell you to skip. Ages shown are the manufacturer’s own rating, not ours.
The one question that decides this
Will somebody reliably sit down with the child in the week the box arrives?
If yes, a subscription is genuinely good: it produces a monthly ritual, it removes the choosing, and it arrives in a form factor children find exciting for reasons that have nothing to do with the contents.
If the honest answer is “most months, probably”, buy a box instead. The failure mode of a subscription is not a bad project, it is three unopened boxes on top of the fridge and a monthly charge nobody wants to cancel because they feel guilty about it. We have no data on how often that happens and we are not going to invent any — but it is the risk the format carries, and no review that ignores it is being useful.
The annual arithmetic, which nobody publishes
The arithmetic
What twelve months actually buys
| Kiwi Crate — projects per month | 1 |
|---|---|
| Kiwi Crate — projects across a year | 12 |
| Tinker Crate — projects across a year | 12 |
| MEL Chemistry — experiments per month | 2-3 |
| MEL Chemistry — experiments across a year | 24-36 |
| NatGeo Mega Science Lab — experiments, one purchase | 130+ |
| Snap Circuits Classic — projects, one purchase | 305 |
The honest reading: subscriptions buy ritual and novelty, not volume. If what a household needs is more things to do, a single large open-ended set delivers dramatically more per pound. If what it needs is a reason to do something on a Tuesday in February, the subscription is doing something a box cannot.
Choosing the right rung
KiwiCo publishes bands that are worth respecting rather than stretching: Kiwi Crate 6-9, Tinker Crate 9-12, Eureka 12+. Atlas Crate covers 6-12 on geography rather than STEM.
The most common mistake is buying up, on the theory that a bright child will manage. It goes wrong more sharply here than with a normal toy, because a subscription that is too hard produces twelve consecutive disappointments rather than one.
The second most common is buying a chemistry subscription for a child under ten. MEL Science rates its chemistry at 10+ and ships a solid fuel stove — that rating is about the contents, and it is not one to stretch.
Say the unwelcome thing
Do not buy a twelve-month plan first
Every provider here publishes shorter plans — KiwiCo lists monthly, three, six and twelve-month options. Start with the shortest one that is not punitively priced.
The thing you are testing is not whether the projects are good. It is whether your household actually does them, and three months tells you that. Twelve months tells you the same thing nine months later.
What to buy
- 6 to 9, adult available: Kiwi Crate, three-month plan first.
- 9 to 12, mechanically curious: Tinker Crate, unless the child is fast — in which case a big open set is better value.
- 10+, real chemistry, adult reliably free: MEL Chemistry.
- Any age, unpredictable schedule: not a subscription. A single large kit or a microscope.
In full
Every pick, and what is wrong with it
Published specifications only, each linked back to the page it came from. Where a manufacturer publishes nothing, the row says so — we do not fill blanks in.
1. Best for 6 to 9
Kiwi Crate monthly subscription
KiwiCo · Kiwi Crate · maker rates it 6-9
One hands-on STEAM project a month, pitched at exactly the age where a child can mostly do it alone.
- Stated age
- Ages 6-9
- Cadence
- “a brand-new project delivered to their door each month”
- Plans
- Monthly, 3-month, 6-month or 12-month
- Subject
- “hands-on STEAM”
KiwiCo publishes Kiwi Crate as hands-on STEAM for ages 6-9, with a brand-new project delivered each month and plans available monthly, three-monthly, six-monthly or annually.
Six to nine is the sweet spot for this format for a specific reason: it is the age at which a child can follow illustrated instructions largely unaided, but still wants an adult to show the result to. Below six the adult does the build; above about ten a single monthly project starts to feel thin.
The published ladder is the other advantage. A household that starts at Kiwi Crate has an obvious step to Tinker Crate at nine and Eureka at twelve, without having to re-choose.
Replay signal
- Open-ended or one-shot
- Each crate is a one-shot build; the subscription is what creates the repeat
- Does anything run out
- Every crate runs out. That is the model, not a flaw — you are buying twelve projects, not one toy
- Room to grow
- KiwiCo publishes a ladder by age: Kiwi 6-9, Tinker 9-12, Eureka 12+
Why we say so: KiwiCo publishes the age bands and the one-project-per-month cadence. A subscription's replay value is structural — it arrives again next month — which is a different thing from a toy that keeps getting picked up, and the two should not be compared as if they were the same.
What’s wrong with it
Each crate is a single build. If a month is busy and the box goes unopened, that month is simply lost — there is no catching up.
| Stated age | Ages 6-9 |
|---|---|
| Cadence | “a brand-new project delivered to their door each month” |
| Plans | Monthly, 3-month, 6-month or 12-month |
| Subject | “hands-on STEAM” |
| Consumables | Yes — each crate is built once |
Every figure above is from KiwiCo, monthly crates by age. Blanks are shown as “not published” rather than filled in.
2. Best for 9 to 12
Tinker Crate monthly subscription
KiwiCo · Tinker Crate · maker rates it 9-12
The engineering rung: monthly builds that are machines rather than crafts.
- Stated age
- Ages 9-12
- Subject
- “learn how things work and create new inventions” through monthly hands-on STEM kits
- Cadence
- One project per month
- Plans
- Monthly, 3-month, 6-month or 12-month
KiwiCo publishes Tinker Crate for ages 9-12, described as learning how things work and creating new inventions through monthly hands-on STEM kits.
The shift from craft to mechanism is the point of this rung. A nine-year-old who has outgrown decorating things wants something with moving parts and a reason for them, and that is what these builds are.
The scheduling caveat is sharper here than at the younger band. A motivated eleven-year-old will finish a monthly project in a single evening, and the remaining three weeks are dead time. For that child, a big open-ended set like Snap Circuits Classic with 305 published projects is better value and always available.
Replay signal
- Open-ended or one-shot
- One-shot per crate, and the builds are more machine than craft at this age band
- Does anything run out
- Yes, monthly by design
- Room to grow
- Steps up into Eureka Crate at 12+
Why we say so: KiwiCo publishes the 9-12 age band, the monthly engineering-project format, and the step up to Eureka Crate at 12+.
What’s wrong with it
Still one project a month. At this age a child who is genuinely into engineering will finish it in an evening and have three weeks to wait.
| Stated age | Ages 9-12 |
|---|---|
| Subject | “learn how things work and create new inventions” through monthly hands-on STEM kits |
| Cadence | One project per month |
| Plans | Monthly, 3-month, 6-month or 12-month |
| Consumables | Yes — each crate is built once |
Every figure above is from KiwiCo, Tinker Crate. Blanks are shown as “not published” rather than filled in.
3. Best for real chemistry
MEL Chemistry monthly subscription
MEL Science · MEL Chemistry · maker rates it 10+
Genuine reagent chemistry monthly, with the equipment supplied once and reused.
- Stated age
- 10+
- Experiments per set
- 2-3
- Cadence
- A new kit by the 23rd of each month
- First shipment
- Includes a home lab — flask, solid fuel stove, safety glasses, beakers
MEL Science publishes 2-3 experiments per monthly set for ages 10 and up, arriving by the 23rd of each month, with the first shipment containing a home lab — flask, solid fuel stove, safety glasses and beakers.
The reusable-lab structure is the smartest thing in this roundup. After month one, each delivery is reagents rather than a whole restart, which is both cheaper for them and less wasteful than twelve boxes of duplicate plastic.
The supervision requirement is not a soft one. This is the only product on this page where an adult being unavailable means the month’s box cannot be opened at all, and that turns a scheduling problem into a subscription you are paying for and not using.
Replay signal
- Open-ended or one-shot
- Guided experiments, not open-ended play
- Does anything run out
- Each month's reagents run out; the equipment from the first shipment does not
- Room to grow
- The reusable home lab means later months arrive as refills rather than restarts
- Adult required
- A solid fuel stove and real reagents at a 10+ rating means an adult in the room
Why we say so: MEL Science publishes the 2-3 experiments per set, the monthly cadence, the 10+ rating and the contents of the first shipment's home lab.
What’s wrong with it
A solid fuel stove and real reagents at a 10+ rating means an adult must be present every single month, not most months.
| Stated age | 10+ |
|---|---|
| Experiments per set | 2-3 |
| Cadence | A new kit by the 23rd of each month |
| First shipment | Includes a home lab — flask, solid fuel stove, safety glasses, beakers |
| Consumables | Yes — reagents are used up each month |
Every figure above is from MEL Science, chemistry subscription. Blanks are shown as “not published” rather than filled in.
4. The alternative to a subscription
NATIONAL GEOGRAPHIC Mega Science Lab
National Geographic · Mega Science Lab · maker rates it 8+
One box, 45 kit experiments plus 85 household ones — available whenever someone is free rather than on the 23rd.
- Experiments in the kit
- 45, across chemistry, earth science and science magic
- Bonus guide
- 85+ further experiments using household items, for 130+ in total
- Includes
- Volcano build, glow-in-the-dark crystal growth, and the tools for both
- Stated age
- 8+
This is here as the honest alternative rather than as a subscription. National Geographic publishes 45 kit experiments plus a bonus guide of 85-plus using household items, rated 8+.
One hundred and thirty published experiments in a box that sits on a shelf until somebody is free is a fundamentally different proposition from twelve arriving on a schedule. It survives a busy month; a subscription does not.
For households where the honest answer to “will someone sit down with them on the 23rd?” is “probably not reliably”, this is the better purchase, and it is usually cheaper than three months of anything above.
Replay signal
- Open-ended or one-shot
- Guided, and the 45 in-kit experiments end. The 85 household ones do not
- Does anything run out
- The supplied materials run out; the household half of the book never does
- Room to grow
- The bonus guide is the genuinely durable part, and it costs the manufacturer almost nothing to include
- Adult required
- Supervision for the chemistry third; the earth science and household experiments are largely self-run
Why we say so: National Geographic publishes 45 in-kit experiments plus a bonus guide of 85+ using household items. That second number is why this kit outlasts most of its price band: roughly two-thirds of the published content needs nothing but a kitchen.
What’s wrong with it
No novelty arriving in the post, which for some children is most of the appeal of a subscription in the first place.
| Experiments in the kit | 45, across chemistry, earth science and science magic |
|---|---|
| Bonus guide | 85+ further experiments using household items, for 130+ in total |
| Includes | Volcano build, glow-in-the-dark crystal growth, and the tools for both |
| Stated age | 8+ |
| Consumables | Yes — the supplied chemicals and crystal compounds are used up |
Every figure above is from National Geographic toys, Mega Science Lab. Blanks are shown as “not published” rather than filled in.
Skip this one
4M Crystal Growing Experiment Kit
4M · 5557 · maker rates it 10+
Bought as a substitute for a subscription, it delivers seven slow results and then nothing.
- Experiments
- 7 crystal-growing experiments
- Contents
- 3 bags of crystal compound, 3 bags of seeding mixture, stirring bowl and spoon, 7 display bases, 7 display covers, 7 ring templates
- Stated age
- 10 years and up
- Consumables
- Yes — the compound is the whole product
This appears in subscription searches because it looks like a recurring thing — several experiments, spread over time. It is not. 4M publishes seven crystal-growing experiments from three bags of crystal compound, rated 10 and up.
The spread over time is the crystals growing, not the child doing anything, and that is a different experience entirely. Somebody shopping for a subscription wants recurring engagement; this delivers recurring waiting.
Replay signal
- Open-ended or one-shot
- One-shot, seven times over
- Does anything run out
- Definitively. Three bags of compound, and when they are gone the kit is a set of display cases
Why we say so: 4M publishes three bags of crystal compound across seven experiments. That is the arithmetic that decides this purchase: it is seven results, spread over weeks because crystals take days to grow, and then it is finished. Excellent as an event; poor as the main present.
What’s wrong with it
Three bags of compound, days between action and result, and a 10+ rating — none of which is what someone shopping for monthly engagement wants.
| Experiments | 7 crystal-growing experiments |
|---|---|
| Contents | 3 bags of crystal compound, 3 bags of seeding mixture, stirring bowl and spoon, 7 display bases, 7 display covers, 7 ring templates |
| Stated age | 10 years and up |
| Consumables | Yes — the compound is the whole product |
| Time per experiment | Days, not minutes — crystals grow on their own schedule |
Every figure above is from 4M, Crystal Growing Experiment Kit. Blanks are shown as “not published” rather than filled in.
We are not putting a buy button on this one. It is easy enough to find if you want it anyway — but we would rather send you to something that gets played with twice.
Questions people actually ask
Frequently asked
Are STEM subscription boxes worth it?
They are worth it if someone will reliably sit down with the child in the week the box arrives. They are poor value if boxes accumulate unopened. Price them as twelve projects across a year rather than as a toy, and compare that against a single large set — Snap Circuits Classic publishes 305 projects in one purchase.
What ages are KiwiCo crates for?
KiwiCo publishes Kiwi Crate for ages 6-9, Tinker Crate for 9-12, and Eureka Crate for 12+. Atlas Crate covers 6-12 on geography. Buying up a band goes wrong more sharply here than with a normal toy, because it produces twelve consecutive disappointments rather than one.
What is the difference between Kiwi Crate and Tinker Crate?
Age band and emphasis. Kiwi Crate is hands-on STEAM for 6-9 and leans toward making things. Tinker Crate is for 9-12 and leans toward mechanisms — how things work and building inventions.
Is MEL Chemistry suitable for a nine-year-old?
MEL Science rates it 10+, and that rating is about the contents rather than the difficulty: the first shipment includes a solid fuel stove and the monthly sets contain real reagents. It is not a rating to stretch. Chemistry sets by age.
Should I buy a twelve-month subscription?
Not first. Start with the shortest plan that is not punitively priced — KiwiCo publishes monthly, three, six and twelve-month options. What you are testing is not whether the projects are good but whether your household actually does them, and three months answers that.
Sources
Where these figures came from
Every specification on this page traces to one of these. If a manufacturer publishes nothing on a point, the page says so rather than filling the gap.
Read next
Where to go from here
Back to Science Kits, or read how we pick.