MTG Card Size Guide: Official Dimensions, Sleeve Specs, and Why Proxies Fit
MTG card size is exactly 2.5 inches by 3.5 inches (63.5mm × 88.9mm), with a thickness of 0.012 inches (0.305mm) and a 2.5mm corner radius. Every Magic: The Gathering card — from a 1993 Alpha Lightning Bolt to a 2026 Showcase reprint — is cut to the same spec, and that spec is defined in the Comprehensive Rules under rule 108.2a. It is the single reason a Standard sleeve fits a Pokémon TCG card, a Lorcana card, a Sol Ring from 1993, the proxy you printed last Tuesday, and a Custom Card Artwork order from our shop. If you are building a deck, ordering sleeves, or evaluating a proxy vendor, the official size is the first number that has to be right. Per the Wizards tournament policy, every traditional card in your deck must fall inside those tolerances — anything outside the spec is marked as a proxy or illegal for sanctioned play.
This guide covers the exact dimensions, the sleeve size they call for, how MTG compares to other TCGs, what to look for in a proxy print, and the four real-world ways the spec gets violated. If you have ever had a card stick in a sleeve, pop out the corner of a deck box, or shuffle a deck that felt thicker than the one you played last week — this is the spec behind all of it.
The Official Size, Broken Down
A standard MTG card is what the playing-card industry calls Standard American Poker size. The deck has used this exact dimension since 1993 because Wizards of the Coast contracted Cartamundi — a Belgian card manufacturer — to produce the first print runs. Cartamundi still makes the cards today, and the cut tolerance on a 2026 print run is the same as it was on a 1993 Alpha print. If you stack a Black Lotus from 1993 next to a Sol Ring from last week, the height, width, and corner radius will line up to within a hair.
Three numbers define the spec:
1. Width and height: 63.5mm × 88.9mm (2.5″ × 3.5″). Rounded down to 63mm × 88mm in marketing material, but the cut is decimal-precise. Measure with calipers and you will see 63.5, not 63. 2. Thickness: 0.012″ (0.305mm) for non-foil, ~0.014″ (0.35mm) for foil. The thickness is what makes a deck feel “right” when you shuffle it. A deck of 60 non-foil cards should be about 18mm thick at the long edge. 3. Corner radius: 2.5mm (1/10″). The cut is deliberate — it prevents the corners from dog-earing during a riffle shuffle and protects the card from chip damage at the most common wear point.
If you are buying proxies, every one of those three numbers has to match the Wizards spec. A proxy that is 0.5mm too tall will not fit a KMC Perfect sleeve. A proxy that is 0.05mm too thick will make a 60-card deck feel like 70. A proxy with sharp 90-degree corners will dog-ear in a riffle shuffle within two games.
MTG vs. Other TCGs
MTG shares its size with two other major TCGs and one that uses a smaller cut. The table below is from a side-by-side measurement of all major TCGs and the QP Market Network TCG size database:
The practical takeaway: if you have a stack of Standard-size sleeves, they fit MTG, Pokémon, Lorcana, and standard poker cards interchangeably. If you try to sleeve a Yu-Gi-Oh card into a KMC Perfect, the card will rattle inside. The reverse — a Yu-Gi-Oh sleeve on an MTG card — fits but leaves 4.5mm of slack at the bottom, which makes the deck feel sloppy and the cards slide during a riffle.
The Sleeve Spec — What “Standard” Actually Means
Every major sleeve brand markets its product as “Standard” or “MTG size.” The internal dimensions those sleeves are cut to are 66mm × 91mm — 2.5mm of clearance in each direction. That clearance is engineered: it lets the card slide in without forcing it, and it stops the card from rattling once sleeved. The math works out to about 1.25mm of play on each side, which is enough to compensate for the corner radius and the slight cut variance between print runs.
KMC Perfect (the Japanese-made inner sleeve most double-sleevers use) measures 66mm × 91mm exactly. Dragon Shield Matte is 66mm × 91mm. Ultra PRO Eclipse is 66mm × 91mm. Kattobi is 66mm × 91mm. If you measure a sleeve and the dimensions are off by more than 0.5mm in either direction, you have either a defective product or a sleeve cut for a different TCG.
The thickness of a sleeve matters as much as the cut. A 60-card deck sleeved in 100-micron KMC Perfects is about 19.5mm thick — roughly the same as a 60-card deck in 80-micron Dragon Shields. If you switch from one brand to another, the deck feels different in the hand. Most players settle on a single brand and stick with it for the consistency.
The Four Ways the Spec Gets Violated
Most “bad” proxies are not bad because the print is low-resolution or the colors are off. They are bad because the print violates one of these four spec points. When you evaluate a proxy vendor, run their sample through these checks before you order a full deck.
1. Over-tall or over-wide. A 0.5mm cut variance — common with low-end digital printers — pushes the card just past 64mm wide. The card still fits a Standard sleeve by force, but the corner sticks out, the top-loading deck box won’t close, and a judge will call it as a marked card in any sanctioned event. The fix is to measure with calipers before you order in bulk.
2. Over-thick. A 14pt or 16pt cardstock makes a 60-card deck feel like 70. Double-sleeving a deck of 14pt proxies forces the inner sleeve to stretch, which tears it after 3-4 shuffles. The fix is to spec 12pt (300gsm) or 14pt (350gsm) blue-core cardstock and reject anything heavier. 350gsm is the sweet spot for premium proxies — same weight as a real card, slight stiffness that holds up to double-sleeving.
3. Sharp corners. A 0mm corner radius (a 90-degree cut) is the most common manufacturing defect on cheap digital prints. The corner snags in a riffle shuffle, dog-ears after two games, and chips if you clip the deck. The fix is to require a 2.5mm corner radius on the order spec — premium printers cut with the same die Cartamundi uses, so the radius is built into the die.
4. Wrong color core. A card printed on solid white cardstock has a “glow” when held up to a light — you can see the back of the card through the front. Real MTG cards use a blue or black opaque core (depending on the era) specifically to prevent that glow. The fix is to require blue-core or black-core cardstock. White-core proxies are the easiest tell that you are looking at a home print, not a premium service.
How to Verify a Proxy Print in 30 Seconds
Once you have a proxy deck in hand, four field tests confirm whether the print meets spec. None of them require a caliper or a light box — just your hands, a sleeve, and a real Magic card for comparison.
1. Calibrate against a real card. Drop a real Magic card on top of the proxy. The edges should line up flush. If the proxy is taller or wider, you have a cut violation. If it is shorter or narrower, the print was scaled down (a 95% scale print is the most common home-printer error). 2. Sleeve test. Drop the proxy into a KMC Perfect. It should slide in with about 1.25mm of play on each side and no force. If the card sticks or the sleeve bows, the proxy is over-thick or the cut is off. 3. Shuffle test. Bridge-shuffle the proxy into a 30-card stack 20 times. The corners should not dog-ear and the edges should not chip. If the corners fray, the cut is too sharp. 4. Light test. Hold the proxy up to a strong light source. You should see a faint blue or black glow through the center, not a clear view of the back. A clear glow = white-core cardstock = home print.
If the proxy passes all four, the print meets the spec. Order the full deck. If it fails any, request a sample of the same spec from another vendor and compare.
The Bottom Line
The 2.5″ × 3.5″ Standard American Poker spec is the foundation everything else rests on. Sleeves, deck boxes, toploaders, playmats with card wells, judge calls at sanctioned events, and the shuffle feel of a 60-card deck all assume that spec is met. When you order proxies, the only number that matters first is the cut.
A 100-card Commander deck printed at the right spec costs US$80 at MakeProxyCard’s tier 91-198 bulk rate — the same total whether you go with KMC Perfect-sleeved playability or a full-art Booster Pack. The proxy deck shuffles, sleeves, and double-sleeves exactly like a paper deck.
Our proxies are cut on Cartamundi-spec dies with a 2.5mm corner radius, printed on 350gsm blue-core cardstock at 0.305mm thickness. They pass the four field tests above, fit a KMC Perfect sleeve with 1.25mm of play, and shuffle into a real deck without sticking. For a deck that costs US$1.60 per card to start and US$0.80 per card at bulk tier, the spec is the one thing we will not compromise on.
Related Reading
- MTG Proxy Prices 2026: How Much Do MTG Proxies Cost? Bulk tier pricing, Commander math, and how to hit your best rate.
- How to Spot Quality MTG Proxies (And Avoid the Bad Ones) Six quality benchmarks including cardstock weight and finish types.
- Proxy Card Sleeves and Backs: What Tournament Players Should Know Five sleeve types ranked, plus the double-sleeve workflow.
- The Complete MTG Proxy Guide 2026 (Pillar Page) Topic cluster hub linking 30+ proxy guides across legality, cost, quality, formats, and etiquette.
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