How to Build a Cube: Size, CubeCobra, Budget, and Proxies

Welcome to Level 4. Up to now you have been a drafter at someone else’s table. Sooner or later, many Cube drafters want a box of their own. It is one of the best projects in the hobby: part collection, part game design, part hosting. It is also easy to overbuild. This lesson is the short path to a first Cube your friends will want to draft, and the rest of the level shows how to balance it, improve it, and host it.

Start with what it is for

Before you choose a single card, decide who it is for. A Cube for teaching new players, a Cube for a group of longtime drafters, and a Cube for nostalgia are three different boxes. Our piece What Is Your Cube For? walks through the question, and it saves money later.

Choose a size

Size follows from how many people you expect to draft:

For a first Cube, 360 is the classic choice. It drafts eight people exactly, and the group learns it fast. Bigger Cubes cost more and take longer to learn. Our guides to Cube pack size and the 720-card Cube cover the tradeoffs.

Copy a list first

Do not design your first Cube from scratch. Copy a proven list, then change it over time.

CubeCobra is the usual place to start. It is an open-source website for building, managing, and playtesting Cubes. Owners post their lists there, so you can browse them, export one as your shopping list, and start your own from it. It also lets you draft a Cube solo against computer drafters, and its analytics help you check your Cube’s balance.

Look for a list that matches your budget and your group, with a primer and a long history of changes. A list that has been edited many times has usually been drafted many times. Then draft it against the bots a few times. You will learn more from two test drafts than from an evening of reading.

Our guide to building a first Cube goes step by step, and Build a Cube in a Weekend is the fast version.

Build on a budget

The price of a Cube comes almost entirely from a handful of expensive cards. Choose a power level that avoids them.

• Pauper Cube: commons only. The cheapest way to own a full Cube, and a great teaching Cube. See our Pauper Cube guide.
• Peasant Cube: commons and uncommons. A step up in power for a little more. See Peasant Cube.
• Budget high-power Cube: strong rares without the famous price tags. Our budget Cube under $200 shows one approach.

Start with what you already own. Many players have half a Cube sitting in bulk boxes. Our guide to building a Cube from your collection shows how to mine it.

What else goes in the box

• Sleeves. A Cube gets shuffled a lot. Matching sleeves protect the cards and keep any one card from standing out.
• Basic lands. Enough of each type for every drafter, sleeved to match.
• Tokens and counters, for the cards that make them.
• A long box or a case that fits it all.

Keep the colors balanced as you go. Our guides to Cube color balance and Cube land count give working numbers, and Cube building mistakes lists the ten every first Cube makes.

Where proxies fit

Proxies come up in every Cube conversation, so here is the plain version.

A proxy is a stand-in for a card you do not own. Some Cube owners use them, especially for powerful old cards that cost far more than most people can spend. Here is what we could confirm:

• Sanctioned tournaments do not allow player-made ones. The Magic Tournament Rules say players may not make their own proxies. Only the head judge can issue one, mainly to replace a card damaged during the event.
• Wizards has said it does not police playtest cards for personal, non-commercial use. Its 2016 statement described them as things like a basic land with a card’s name written on it, or a printed slip in a sleeve.
• Counterfeits are a different thing. A fake made to pass as a real card, or sold as one, is a counterfeit. Wizards says it works with law enforcement against them.
• Wizards’ Fan Content Policy leaves proxy cards out. It says making counterfeit or proxy cards does not count as fan content. That is why this course will never offer printable proxies.

So in a casual Cube, playtest cards are the owner’s choice. Keep them plainly not real, announce them before the draft, and never sell or trade one. Our article on MTG proxies covers the ethics and etiquette in more depth.

A Cube is never finished

Your first list is a draft, in both senses. After each night, note what nobody picked and what everyone fought over, then swap five to ten cards. Keep a short changelog so your drafters can see the Cube grow. Our pieces on Cube maintenance and updating a Cube show how to keep it fresh without breaking it, and the curation lesson later in this level turns that habit into a routine.