Cube has exactly two truths:
- There are no hard rules.
- If you ignore the boring logistics (size, packs, lands, sleeves), your first cube night gets weird fast.
What is an MTG Cube?
An MTG Cube is a custom draft format where you curate a pool of cards and draft it like a booster draft—except you’re making the packs yourself. Traditionally, cubes start at 360+ unique cards, but Cube can be whatever you want it to be. Yes, that includes silly constraints and “because it’s funny” themes.
The “3×15” assumption (why 45 matters)
Most cube math starts with the classic booster-draft structure:
- 3 packs per player
- 15 cards per pack
- That’s 45 drafted cards per player
That’s why you’ll constantly hear “multiples of 45.” If each player drafts 45 cards, then every +45 cards in your cube supports one more drafter (assuming the standard structure).
The core formula:
- Cards needed = Players × 45
- Players supported = Cube size ÷ 45
So:
- 360 supports 8 players (8×45)
- 450 supports 10
- 540 supports 12
- 720 supports 16 (or two 8-player drafts without reshuffling)
Cube sizes that actually make sense (and what they feel like)
Here’s the practical view. This table assumes the classic 3×15 draft.
| Cube size | Max players (3×15) | Common use | What it feels like | The tradeoff |
|---|---|---|---|---|
| 180 | 4 | Small group cube | Focused, repeats often (in a good way) | Less variety; narrow themes need careful density |
| 360 | 8 | The “first cube” default | Consistent environment; every card shows up in an 8-player draft | Can feel samey if your group plays constantly |
| 450 | 10 | “More variety” without going huge | You draft 360 of 450 with 8 players, so each draft changes | Slightly less consistency for synergy decks |
| 540 | 12 | Variety sweet spot | 8-player drafts see ~2/3 of the list, so it stays fresh | More shuffling, more storage, more balancing work |
| 720 | 16 | Big lists / events | Tons of novelty, room for pet cards | Harder to tune; unique effects show up less often |
The sneaky lesson: bigger cubes buy you variety, but they also increase the workload—more sleeves, more shuffling, more storage, and more “why didn’t the deck come together?” moments if your themes are narrow.
“How big does my cube need to be?” (quick answers)
If you want a dead-simple rule set:
- If you draft like a normal booster draft, 360 is the minimum for 8 players (3×15).
- If you have a small playgroup (2–4), a cube can be as small as 180 and still draft well.
- If you want extra cards for variety, go up in +45 chunks (450, 540, 585, etc.) and just set aside the undrafted cards each session.
How many basic lands do you need?
Enough that nobody is sweating basics while deckbuilding.
A solid, low-stress baseline for an 8-player cube night is 30–40 of each basic land. If your cube runs a lot of nonbasic fixing lands, you’ll need fewer basics in practice—but having extras is cheap insurance for smooth nights.
Does a cube have to be singleton?
Nope. Singleton is common because it’s fun and varied, but duplicates are totally valid.
People break singleton for a bunch of practical reasons:
- Redundancy (so an archetype shows up more often)
- Fixing lands (because good mana makes better games)
- Unique effects that don’t have many close substitutes
- Lowering complexity (fewer one-off weird cards for newer drafters)
The best rule is: run what makes your cube draftable and fun, not what makes it “official.”
Archetypes and themes: how much support is “enough”?
This is where new cube builders overthink themselves into paralysis.
There’s no universal formula for “how many cards support an archetype,” because it depends on:
- how consistently you want that deck to appear
- how contested the pieces are
- how much overlap the archetype has with other decks
Also: you don’t need the “ten guilds = ten archetypes” structure. It’s common because it’s tidy, but lots of great cubes use looser “lanes” (aggro, midrange, control, plus some synergy seasoning) or uneven themes that match what the playgroup likes.
What you need to host a cube draft (the not-glamorous checklist)
You can absolutely run cube with “a pile of cards and a dream,” but a tiny bit of prep makes it feel smooth and intentional.
- A fully sleeved cube (matching sleeves; mismatched sleeves turn into marked-card drama)
- A basic land station (pre-sleeved if your cube is sleeved)
- Tokens / dice (or a simple substitute like dry-erase tokens)
- A pack plan (how many players, how many packs, when you stop)
- A way to store it that won’t explode in your backpack
The most important FAQ: “Do I need to make it perfect before we draft?”
No—and you shouldn’t try.
Your first draft is how you learn what your cube actually is:
- Is mana working?
- Are games ending in a fun window?
- Are there enough cheap plays?
- Do certain cards rot in sideboards every time?
Cube gets good through iteration. Draft, adjust a small batch, draft again.