Cube Generator

Play rate

A card's play rate is how much constructed Magic plays it: for each format in the Meta Lens data (Vintage, Legacy, Duel Commander, Modern, Pioneer, Standard, Pauper), the share of decks on file that run it in the main deck, with a deck that runs it only in the sideboard counting a quarter, since sideboard cards like Rest in Peace are narrow in a cube. Each card pool weighs the formats that fit it (a Legacy cube leans on Legacy and Duel Commander, a Pauper cube on Pauper alone; a cube from chosen sets weighs every format on file alike), and adds a small tiebreak from EDHREC rank for cards no deck on file runs. The seed moves every score up to 15% either way, so another seed gives another cube from the same pool. A theme raises matching cards (by role tags, rules text or type) to 1.6 times their score plus a small fixed amount, so on-theme cards with little constructed play still get in. The play-rate floor keeps a card only when some format on file runs it in at least that share of its decks.

play rate = sum over formats of (format weight x share of that format's decks running the card) + small EDHREC tiebreak

From chosen sets

Pick any of the sets the site knows (Scryfall's list, less token, promo, memorabilia and minigame sets). A draft set counts the cards its boosters held: a card is in a set when one of its printings there is found in boosters, by Scryfall's booster field, so starter kit cards numbered in the set (Serra Redeemer and four others in Dominaria United) and a Commander Legends deck's reprints stay out; other sets keep every card. Each set's row counts its cards once each, at the rarity printed there, and how many of them each format allows today; the counting runs in a worker so the page stays quick. A card printed in more than one chosen set counts once in the cube, and when it was printed at more than one rarity in those sets, it counts at the lowest. Then the rules, each with the count it leaves: rarity (as printed in the chosen sets; special rarity goes with rares and mythics), colors (lands are kept or left by the card type rule instead), card types (the front face), the play-rate floor, the budget and your Collection.

Size: every card that passes, or a size, which the slots below fill by play rate. Copies: one of each; by rarity, as Lucky Paper's set cube (4 of each common, 2 of each uncommon, 1 of each rare and mythic); or the same number of each. Basic lands are kept beside the cube, not in its packs or its card count, and go into the text and .dek lists only when you ask. Beside the rules, a table shows the cards that pass in each color against the slots a cube of that size gives, and how many times over each color could fill its slots.

Who gets in

The card pool is every card legal in the chosen pool (Vintage, Legacy, Modern or Pioneer legality; the Pauper cube means a common printing on paper or Magic Online, which is Scryfall's Pauper legality with Pauper's own banned cards kept, as The Pauper Cube keeps them, and the cards every format bans left out; the Peasant cube means a common or uncommon printing of a Vintage-legal card, the cube convention, not the Peasant constructed format, which allows five uncommons a deck and has its own list; the Arena pool means cards on MTG Arena), or the chosen sets, minus basics, the ante cards (their rules text plays for ante, and every format bans them), and card types that aren't played in a game (conspiracies, schemes, planes, attractions, contraptions, stickers and the like), then the rules. A card that mentions a commander (Minsc & Boo, Timeless Heroes, Fierce Guardianship) is a real card and stays. Creatures count by their front face, as the card type rule reads it, so Fable of the Mirror-Breaker and the Invasion battles count as what they are when cast. Slots: 8% lands (6% for Pauper and Peasant), 10% gold cards, 8% colorless cards, and the rest split evenly across the five colors. Inside a color, cards go in by play rate while the curve has room (targets of 16% at one mana, 26% at two, 22% at three, 16% at four, 11% at five and 9% at six or more), with creatures and noncreature spells each capped at 60%, and then the lowest play-rate cards give way to removal, counterspells and bounce until 15% of the color can interact. Gold cards are split evenly across the ten color pairs; lands start with one land that makes both colors of each pair. The filling runs in a worker.

Players and formats

Choose the players (2 to 16, where the format allows) and a way to draft: booster draft, Pick-Two, Rochester, Rotisserie, burn draft (Glimpse), sealed, team sealed, Winston, Grid, Winchester, Solomon or Housman. Each is written as its source states it, with the source linked, and the page works out the night: the cards it deals out, what each player ends with, the packs and pack size, and for a cube, how many cards stay in the box and what share of the cube is dealt, which is also the chance a given card is in play that night when the cards are dealt at random. In Rotisserie every card is face up and chosen, not dealt, so it isn't a chance there. Draft Sim seats you first in Rotisserie's snake unless you choose another seat or a random one. A cube too small for the choice says by how much, the most players it seats at those settings, and the pack size or pick count that fits. Where a source leaves a number open, the page says what it assumes (burn draft's last pass; Winchester's card count for 3 or 4 players).

booster draft: cards = players x packs x cards a pack; each player drafts packs x cards a pack

burn draft: picks a pack = cards a pack / (1 + cards burned with each pick), rounded up

share of the cube dealt = cards dealt / cube size; cards left in the box = cube size - cards dealt

Times, from the Magic Tournament Rules, Appendix B: a booster draft with the pick clock (40 seconds for a full pack down to 5) and a review period after each pack but the last: "The time for review after the first booster pack is 60 seconds. Each subsequent review period increases by 30 seconds." So 60 and 90 for three packs, then 120, 150 and on for more. Rochester: "The review period for a booster after it has been laid out on the table and before the first card is drafted is 20 seconds. Players have 5 seconds for each pick."

booster draft time = packs x (the clock for one pack) + 60 + 90 + ... (one review after each pack but the last)

Rochester time = packs opened x (20 + 5 x cards a pack) seconds; 8 players, 3 packs of 15: 24 x 95 = 2,280 seconds, about 38 minutes

Rotisserie: two or three hours in person (Lucky Paper). Winchester for three or four players follows Lucky Paper's page: "Add another 40 or 45 cards for each player", and "Each player builds a 40+ card deck from their draft pool"; the page lets you choose 40 or 45 (45 to start). Pick-Two follows Wizards' Pick-Two Draft page, a tabletop format for 4 to 7 players: "players always select two cards from each booster pack", and "each player will have about 42 cards" from three Play Boosters of 14; from a cube, packs of 15 give 45.

A Captain cube and the Admiral Phase

Captain drafts open with the Admiral Phase (Chad's league charter: "Admiral Phase first: snake-draft Captains before anything else"): legendary creatures that can take the Seat only, 8 to 12 Captains each, then the main draft. On the players and formats tab, switch it on for any cube: the page states how many Seat-eligible legends the phase uses against how many the cube has, what that leaves for the main draft, and the cube's legends by color identity (each pair exactly, and those holding both of a pair's colors), as counts.

legends used = players x Captains each (Winston: 2 x Captains each; Grid: 9 x the grids that give each player at least that many)

"A Captain cube" builds one: the legends the phase uses plus the legends kept for the main draft (10 unless chosen), into slots, then the rest of the cube from the rules above with Seat-eligible legends left out. Two players drafting Winston unless chosen.

pair slots = 60% of the legends / 10, to the nearest whole number (at least 1); single-color slots = 25% / 5, rounded down (at least 1); the rest: three or more colors and colorless

size = the smallest multiple of 45 holding the legends used plus the main draft's cards, and at least 180

Each slot takes legends by play rate, as every card here is chosen; a slot the card pool can't fill passes its count on to the rest. The cube opens on its night with the Admiral Phase on, and Draft Sim starts it that way.

A Captain cube is held to Captain's lists unless you choose "Cracked cube": its card pool is Captain's own, it holds no card on the banned list or the Reserved List, no legend on Banned as Captain goes into the Admiral Phase, and it holds at most the Game Changers chosen for each player's pool (3, Comp's limit for a deck, unless chosen), the legends' first by play rate. The cube says what it holds ("0 banned, 0 Reserved List, 6 Game Changers"), and its list marks each Game Changer. From the Captain page, Cube Generator opens with the Captain cube builder first.

Game Changers in the cube <= Game Changers for each player x players

The cube night tab keeps no log of its own: every match is logged once, in the game diary, carrying the cube's id, and the record by colors is read from there (a deck's colors: its Captain's color identity, else its spells' colors). Matches logged from a Draft Sim deck drafted from the cube carry it too.

The balance check

For any cube, generated or brought in: each color's cards, creatures, removal, interaction, card draw, average mana value and curve, and each color pair's gold cards, fixing lands, the cards and removal it can cast, and what its gold cards wait for with how many cards supply it and wait for it. Removal and the themes are read with Set Lab's rules: removal is a card whose card facts say it can exile, destroy, damage, shrink, make its controller sacrifice, put into the library, take or shut off a creature, confirmed by a line of its text; a pair's themes are what its gold cards wait for, read sentence by sentence with the Interaction Oracle's reader, and a card supplies a theme when a line of its own text (or a card fact) says so. Interaction counts cards whose role tags include spot removal, board wipes, edicts, counterspells, bounce, pacifism effects or theft. Every count counts each copy.

Against the night on the players and formats tab: what a pack holds on average and what a player's pool holds if the cards came at random.

per pack = count x cards a pack / cube size; per player = count x cards each player ends with / cube size

It lists a line, with the count and the threshold, when a color's count is more than 15% off the average, when its interaction is under 15% of its cards (or under 60% of the colors' average, a check that leaves green out unless you tick it in, since green has the least interaction in most cubes), when it's under 30% creatures or under 30% one- and two-drops, when removal comes to under 2 a pack, when a pair has no gold cards or no land that makes both its colors, when fewer than 4 cards a pair can cast supply what its gold cards wait for, when gold cards are over 12% of the cube while lands are under 6%, when the list isn't singleton, and when the cube is too small for the night. Every threshold can be changed on the page, and is kept in this browser; each runs from 0 to 100, and a number typed outside that is set to the nearest end, in the box too, with a note.

Lists in and out

In: plain text (one card per line, counts and set codes allowed, a sideboard section skipped; a line that is a card's whole name is that card before any count or set code is read off it; a count is a number under 1,000, so 1996 World Champion is a name; and a set code is written in capitals or lower case, so Hazmat Suit (Used) keeps its (Used)), Cube Cobra's CSV export (its name, set and collector number columns; maybeboard rows skipped), Draftmancer card lists (settings and custom card blocks skipped) and MTGO .dek files. A row or line with a set code and collector number is found by those first, in Scryfall's printings, so a card printed under another name (Universes Within and Secret Lair renames: "Kefka Palazzo" in FCA is Purphoros, God of the Forge) is the card it is, and the balance tab lists each one found that way. A printing found that way whose card isn't in the card list cubes are built from (an acorn card, a non-tournament promo) is listed apart, with its set and number. Other names are matched to the site's card list; lines that don't match are listed. Out: a text list with counts, a CSV with Cube Cobra's column names (a row for each copy), and an MTGO .dek file; each reads back into the page card for card. A share link carries the whole list, compressed, in the address itself, and opening it shows the cube under a banner with “save a copy”; nothing is uploaded, and a link's names are matched to the site's card list. A link opens up to 12,000 different cards and 250 copies of one (the cap for an imported list); past either, the page says what it left out. The printable pick list goes by color, a box to tick for each card, and prints without the rest of the page.

Versions

Every save keeps a version: what was added and cut, with the date. Changes within ten minutes are one version; up to 300 are kept. Bringing a version back is itself a version, and can be undone. Compare sets any two versions, cubes, pasted lists or share links side by side, by name.

Pack rules

A pack is slots, each a Super Search query and a count. Packs are dealt with the most restrictive slot first, a card used once at most, and cards named together (a bundle) placed in the same pack; a slot with nothing left is filled from the rest of the cube, and the sample packs and the draft say how often. A query matches a card on either face, as Super Search does.

Drafted 1,000 times

Draft Sim runs the cube with its pick model in every seat (about one seat in six on the top-player fit), the cube's own pack rules if it has them, seeds sim-1 to sim-N so a run can be repeated. For each card: how often it was dealt and taken, its average pick, how often it was a first pick, and how often it made a deck; for each color pair, how many decks. The cube rating it uses is 60% constructed play rate and 40% a reading of the card text, so these are counts of a model, not records of real cube drafts.

Sources

• Meta Lens decklists (see the Meta Lens page for its sources and dates): the play shares behind the play rate.
• EDHREC rank as published by Scryfall: the tiebreak.
• Card roles, answer methods and effect classes from the site's card facts data; legality, sets, printings and prices from Scryfall.
• The draft formats and cube sizes, read September 25, 2026: Lucky Paper's format guides (booster, Rochester, Rotisserie, Winston, Winchester, Grid, Solomon, burn, Housman, team sealed), Lucky Paper's cube FAQ and set cubes articles (Anthony Mattox), Wizards' Winston Draft (2005), Wizards' Arena Cube Draft (September 8, 2025: 540 cards), Magic Online's Vintage Cube (540 cards), MTG Wiki's Pauper Cube page (450 cards), Draftsim on Commander cubes, MTG Salvation's two-player guide and Rochester basics, and Wikipedia's formats page for Rochester's pick order.
• Magic Tournament Rules (effective February 27, 2026), Appendix B: the pick clock, the review periods and Rochester draft timing, quoted above; read September 26, 2026.
• Wizards of the Coast, "Pick-Two Draft" (the formats page) and Lucky Paper, "Winchester", read September 26, 2026.
• Which cards a set's boosters held: Scryfall's booster field, read with its search (-is:booster game:paper) September 26, 2026, matched against every paper printing's set and collector number. It applies to draft sets (expansions, core sets, Masters and draft innovation sets).