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What size battlemap do you actually need? A grid math guide
Every map vendor lists a resolution — 1K, 2K, 4K — like it’s supposed to mean something to you. It doesn’t, not on its own. A 2048-pixel-wide image could be a comfortable single room or a blurry mess stretched across forty squares, and the number alone won’t tell you which. What matters is squares per side, and that depends on a second number almost nobody puts on the box: pixels per square.
This is the math, worked all the way through, so you can look at any map file and know in advance whether it’ll hold up on your screen or your table.
Start from the grid, not the pixel count
D&D 5th edition (and most of the systems built on its chassis) runs on a five-foot grid: one square equals five feet, which is roughly the space a medium creature needs to fight in. Every resolution decision downstream of that is really a question of “how many five-foot squares am I trying to fit into how many pixels.”
So the real unit you’re buying isn’t “2K.” It’s “2048 pixels, divided across however many squares wide the room is.” A tiny guard closet at 2048 pixels wide looks incredible. A sprawling forty-square great hall at the same 2048 pixels looks soft, because each square is only getting about 50 pixels to work with.
Pixels per square: what your VTT actually expects
Virtual tabletops render maps by dividing them into a grid and snapping tokens to it, and each platform has conventions for how many pixels a “clean” square should be:
- Roll20 shipped for years with a 70-pixel-per-square default. Plenty of legacy map packs still target this, and it’s still a safe floor for readability at typical zoom levels.
- Foundry VTT doesn’t enforce a number, but the community has drifted toward 100 pixels per square as the sweet spot for modern, high-DPI displays — enough resolution to zoom in on a token without the map turning to mush.
- Higher-fidelity references (maps meant to be zoomed in tight, or projected on a TV) benefit from 150+ pixels per square, but you pay for it in file size fast.
None of these are hard rules — you can run a 70px/square map on Foundry and it’ll work fine, it’ll just look softer at high zoom than a 100px/square map would. The number is a quality dial, not a compatibility requirement.
1K vs 2K vs 4K, translated into squares
Here’s the part that actually answers the question. Take the pixel width of the map and divide by your target pixels-per-square:
| Resolution | Pixel width | At 70 px/square | At 100 px/square |
|---|---|---|---|
| 1K | 1024 px | ~14 squares | ~10 squares |
| 2K | 2048 px | ~29 squares | ~20 squares |
| 4K | 4096 px | ~58 squares | ~40 squares |
Read that as a ceiling, not a target — a map that exactly fills the frame edge-to-edge with zero margin for walls, borders, or that extra corridor you’ll want to add later. In practice, budget some headroom: a “20-square room” battlemap is more comfortable cast at 2K than crammed to the absolute edge of 1K.
This is also why a single “4K battlemap” claim means very little without context. A 4K image of one 10-square room is overkill — you’ll never see the difference from 2K. A 4K image of a sixty-square dungeon complex, on the other hand, is the only way to keep every room legible.
When 4K actually matters
4K resolution earns its keep in three specific situations:
- Multi-room complexes. A dungeon, mansion, or temple with a dozen-plus connected rooms needs enough total pixels that no individual room gets starved. This is the most common real reason to reach for 4K — not because any one room needs it, but because the whole floor plan does.
- Print. More on the DPI math below, but physical printing eats resolution fast, and 4K is often the minimum for a print that doesn’t look soft on the table.
- Zoomed VTT play. If your table zooms in tight during combat — tracking exact facing, cover, or precise movement — the extra pixels-per-square headroom keeps token-adjacent detail sharp instead of blocky.
If none of those apply — a single tactical room, viewed at a normal VTT zoom, never printed — 1K or 2K will look just as good and load noticeably faster.
Printing a battlemap: the DPI math changes the rules entirely
Screen resolution and print resolution are different units solving different problems, and this is where most people get the size wrong.
The standard physical scale for a printed D&D battlemap is one square equals one inch — that’s what lines up with standard 1-inch miniature bases. So the question becomes: how many pixels does one printed inch need to look good?
- 150 DPI is the practical floor for a battlemap viewed at arm’s length across a table. Below that, edges and text start to look visibly soft.
- 300 DPI is “photograph quality” — the number you’d want if the map might get held up close, photographed, or used as a hero prop.
Run the numbers: a 20-square-wide room, printed at one inch per square, needs 20 inches of paper. At 150 DPI, that’s 3,000 pixels wide — solidly into 4K territory. At 300 DPI, it’s 6,000 pixels — beyond a single 4K frame, which is why large printed maps are often composited in tiles or panels rather than cast as one image.
The short version: if you’re printing, size for inches-times-DPI, not for “4K sounds big enough.”
The short answer
- Casual VTT play, one tactical room: 1K is plenty.
- Multi-room encounters, or anything you’ll zoom in on: 2K.
- Full dungeon complexes, anything headed for a printer, or set pieces you want razor-sharp: 4K.
RealmCast casts at 1K and 2K on every plan, with 4K unlocked on Archmage and above — because the honest answer to “what resolution do I need” is almost always “it depends how many rooms you’re trying to fit,” and we’d rather you pick the right one than pay for headroom you won’t use.