How to build a Magic: The Gathering cube

A cube is a curated set of cards you own that acts as a self-contained draft environment — no booster packs, no randomness, just the gameplay you want every time. Building one is one of the most rewarding projects in Magic, but it starts with knowing exactly what you already have.

What is a Magic cube, exactly?

In a normal draft, players crack random booster packs and pass cards around the table. A cube replaces the packs with a fixed pool of cards you've handpicked and sleeved up. You shuffle the whole pool, deal out packs of 15 cards, and draft just like at a store — except every card in the pool was chosen by you.

The result is a draft experience that stays consistent across sessions, is tunable over time, and costs nothing to run once built. Most cube owners treat their cube as a living project, adding and cutting cards as new sets come out or as they discover which archetypes are too strong or too weak.

How big should a cube be?

The standard size is 360 cards — exactly enough for eight players to each draft three packs of 15. That's the most common configuration because it matches the pod size at a typical game night.

Smaller cubes are absolutely viable:

• 180 cards — works for four players, or two players doing a "rotisserie" style pick.
• 270 cards — comfortable for six players and a bit easier to build balanced archetypes with fewer slots.
• 450–540 cards — popular for groups that want more variety per draft or a "peasant" cube with lots of commons.

For a first cube, 360 is the right target. It's large enough to support eight distinct two-color archetypes (one per color pair) while staying manageable to sleeve and store.

What power level should I aim for?

Power level is the single most important design decision in cube, and there's no universally correct answer — only what's right for your playgroup.

• Vintage / powered cube — the Power Nine, dual lands, and the strongest cards ever printed. Elite gameplay, very high cost if you're buying singles.
• Unpowered / legacy cube — no Power Nine, but still uses format staples like Force of Will and original dual lands. The most common "competitive" configuration.
• Modern cube — cards legal in Modern or printed in roughly the last decade. Easier on the wallet and often more familiar to newer players.
• Peasant or pauper cube — mostly commons and uncommons with a limited number of rares. Extremely affordable and often surprisingly deep.
• Themed cube — built around a specific set, block, mechanic, or aesthetic. Popular options include an Innistrad cube, a tribal cube, or an artifact-themed cube.

If your group plays Commander, a "Commander cube" — where each player drafts a 60-card pool and builds a 30-card Commander deck from it — is a fun hybrid format.

How do I design the archetypes?

A balanced cube supports a predictable number of two-color archetypes so drafters can read signals and build coherent decks. For a 360-card cube, plan on roughly ten archetypes (one per color pair in a five-color format), each needing 20–25 dedicated cards plus access to a shared pool of gold cards, artifacts, and lands.

The baseline color split is simple: divide your 360 slots roughly equally across white, blue, black, red, and green — around 50–55 cards per color — then fill the remaining slots with multicolor cards, artifacts, and lands. Keep at least 40–45 land slots so every drafter can fix their mana.

For each archetype, identify the central game plan (aggro, control, combo, midrange) and make sure the enablers for that plan are spread across both colors. A white-red aggro archetype needs cheap threats in both colors, not all of them in white.

How do I build from cards I already own?

The most cost-effective approach is to start by cataloging what you already have, then identify the gaps. This sounds obvious, but collectors with thousands of cards often have no idea which key cube staples are sitting in boxes they haven't opened in years.

The workflow that works: digitize your collection first, then search your digital library for the cards on your cube list. Every card you already own is one you don't have to buy. For most collectors with a few years of cards, a first cube at Modern power level is largely buildable from existing stock.

Once you know your gaps, build a want list for the remaining cards. Sorting by price lets you prioritize cheap pickups first — many draft staples cost well under a dollar each.

How do I store and maintain a cube?

Sleeve every card — ideally in a consistent opaque sleeve so no card is identifiable from the back during a draft. Most cube owners use a single color or brand of sleeve and replace the set whenever sleeves start showing wear. Worn sleeves are marked sleeves, which breaks draft integrity.

Store the sleeved cube in a dedicated box with dividers separating the colors and card types. Dragon Shield cube shells and BCW 1600-count boxes are popular options. Some owners keep a separate binder or box of "on-deck" swaps — cards being tested as potential replacements — so cuts and additions are easy to make between sessions.

Keep a digital list of your cube's contents updated whenever you make changes. A card that's been physically removed from the cube but is still on the list will mess up your archetype ratios the next time you try to iterate. Many cube owners maintain their list on CubeCobra (a free cube-building tool) alongside their physical inventory in a collection app.

When should I start drafting?

As soon as you have 360 sleeved cards in a rough configuration. A first cube doesn't need to be perfect — it needs to be played. You'll learn more from one four-person draft about which archetypes are too powerful, which cards never get picked, and which synergies people missed than from weeks of theorycrafting.

After each session, ask players which color pairs felt strong, which felt unplayable, and which individual cards overperformed or underperformed. That feedback loop is what turns a rough first draft into a great play experience over time.