A2, A3, or Roll? Sizing TTRPG Battle-Maps for Home Printers

Roll Initiative... and Roll Out a Map!

You’ve crafted the perfect encounter. There’s a tavern with questionable stew, a troll under a bridge with opinions, and your party’s rogue has already tried to seduce the innkeeper’s cat. All you need now is the battlefield, a beautifully detailed TTRPG battle-map to set the stage for glory (or chaos).

But here's the rub: you’ve bought a digital map online, or perhaps you made one yourself, and now you’re staring down the printer tray wondering...

“How the heck do I print this thing at home without summoning a paper elemental?”

Fear not. Whether you’ve got an A4 home printer, a crafty streak, or ambitions of a full table-spanning battlemat, this post will guide you through sizing, printing, and piecing together TTRPG battle-maps like a kobold with a glue stick and a plan.

We'll cover:

• What print sizes mean (A4 vs A3 vs A2 and beyond)
• Grid scaling for miniatures
• Practical printing tips for different home setups
• Tiling software like rasterbator.net
• Tricks for keeping maps modular, storable, and table-friendly

So grab a brew, maybe your favourite dice, and let’s make some map magic happen.

Understanding Map Sizes: A4, A3, and the Glorious Scroll of Doom

Let’s get our bearings with paper sizes. If you’re in the UK or anywhere that uses ISO 216 sizing (basically the A4 system), here’s how things stack:

• A4 (210 × 297 mm) – The humble hero of home printers. Your standard sheet of paper.
• A3 (297 × 420 mm) – Double the size of A4. Many home printers can’t handle it, but copy shops can.
• A2 (420 × 594 mm) – Four A4s stuck together. Perfect for big encounters.
• Roll printing / Plotters – Continuous banner printing used by pro printers. Rare for home use, but achievable with tiling.

Here’s where it gets spicy: most commercial gridded battle-maps (especially those scaled for 28mm miniatures) are designed with 1-inch squares or hexes, and if you’re printing in the UK with A4 paper, that can throw things off just a bit.

So the question becomes less “What size is the image?” and more “How big do I need each square to be, and how much can I fit per page?”

Miniatures and Grid Scale: The Magic Number is 7

When printing battle-maps with 1-inch squares (or near enough, 25.4 mm per side), the reality is that an A4 sheet can fit roughly 7 squares across its shorter edge with a small border.

That’s the number to remember.

Want to print an 8x10 room? You’ll need two A4s, ideally tiled side-by-side.

Want a proper dungeon crawl with winding hallways and a few ambush points? You’re likely looking at multiple sheets, unless you resize the grid.

Now, if you’re printing on A3, that jumps to around 10–11 squares per short edge. Suddenly your forest clearing looks a lot more spacious. A2? You’re in full fortress territory.

The real trick is working out your preferred grid scale and matching the map image size to your physical tabletop footprint.

Digital Maps: Resizing Without Ruining Detail

Most digital battle-maps you download will be supplied as high-res JPEGs or PNGs. Some might even include pre-sized PDFs, but if not, you’ll want to do a bit of tweaking before printing.

Let’s say you’ve got a 24x36 inch map, designed for print shops.

At 300 DPI, that’s 7200 x 10800 pixels. Yikes.

Open that in Photoshop, GIMP, or even the free Photopea in your browser, and resize to something manageable.

If you want it to print over six A4 sheets (3 across, 2 down), work backwards:

• Each A4 sheet = 210mm wide (~8.3 inches), minus margins.
• So 3 sheets = ~24.9 inches wide.
• Perfect. Resize your image to 24.9 inches wide and let your printer software handle the rest.

We’ll talk tiling next.

Tiling Maps at Home: The Kobold’s Favourite Tools

Unless you own a wide-format printer (or a helpful friend at a school graphics department), you’re probably tiling maps onto A4 sheets.

Thankfully, modern kobolds have access to powerful tools:

1. Rasterbator.net

Despite the questionable name, this is a brilliant free web app for turning one big image into multiple sheets.

• Upload your battle-map
• Choose paper size (A4 or US Letter)
• Select output size in pages or metres
• Add optional borders for trimming
• Download a tidy PDF

It’ll even let you overlay a light grid if you forgot to include one. Fancy.

2. Adobe Acrobat (free version)

If your map is a high-res PDF, open it and use Print > Poster. Adjust tile scale to 100% and add overlap (5–10mm) for trimming. It’s not flashy, but it gets the job done.

3. Posterazor (Windows)

Old but gold. Breaks a JPEG into sheets with clear guides. Offers more control than Acrobat, less fiddly than giant Photoshop files.

Whichever tool you choose, you’re creating a jigsaw puzzle of A4 pages, ready to be sliced, trimmed, and taped together like a crafty villain plotting their dungeon layout.

Assembly & Craft: Turning Printouts into Playable Maps

Once you’ve printed your sheets, it’s time to make them table-ready.

Here’s how to do it without summoning the spirit of wonky edges:

1. Trim borders – Use a metal ruler and a craft knife. Line up cuts precisely or leave overlap if using glue.
2. Align the grid – Work from one corner and add each sheet like a tile. Taping the backs helps keep the surface flat.
3. Laminate (optional) – If you want dry-erase capability or durability, consider laminating each A4 sheet individually and reassembling. Or use clear contact paper.
4. Modular Magic – For dungeon crawls or reveal-based maps, consider printing smaller zones separately. Attach magnets or Blu Tack to place them mid-session.
5. Storage – Once assembled, roll the map loosely or store flat in an art portfolio folder. Or trim to specific zones and tuck into envelopes like a secret GM stash.

Printing on A3 and A2: Bigger Is Better (If You Can)

If you have access to an A3 printer, or can pop into your local copy shop, the battlemap possibilities expand exponentially.

A3 maps are a sweet spot. You can print most room-sized encounters on a single sheet, or break larger dungeons into fewer tiles with better alignment.

A2 posters are excellent for boss arenas, large-scale wilderness battles, or tactical city streets.

Remember: the key with larger prints is to ensure your image file is high enough resolution (ideally 300 DPI at target size). Blurry goblins are no fun.

A good local print shop can help, and many accept files by email with same-day pickup. Ask if they’ll print on matte paper for less glare, or synthetic tear-resistant stock for repeated use.

Going Off the Roll: Banner Printing and Scroll Maps

Now, for the ambitious kobolds: roll printing.

A few higher-end home printers can handle banner prints (long continuous paper instead of individual sheets). These are ideal for winding forest paths, desert chases, or sewer tunnels that go on for far too long.

To do this:

• Check your printer specs for “banner mode” or custom page sizes
• Load roll paper (often 210mm wide)
• Set a custom print size (e.g., 210mm × 1200mm)
• Mind your margins and test print in segments

The final result? A dramatic scroll-style map you can unroll with flourish. Very on-brand for ancient ruins or elven temples.

Just… maybe don’t let the cat sit on it mid-game.

Tips for GMs: Map Use, Scaling & Grid-Free Play

We’ve talked printing, but what about actual gameplay?

Not all players (or GMs) like to play with strict 1-inch grid systems. Here are a few alternate methods to keep your sessions flowing:

• Use loose grid guidelines – Print gridless maps and place a transparent acetate grid over the top
• The “7 squares = A4” rule – Just eyeball it. If a room is 3 A4s wide, you know it’s roughly 21 squares across.
• Play theatre of the mind + reference map – Use your map more as a visual aid, especially for exploration scenes.
• Grid overlays – Some players use vinyl sheets with grids drawn on in permanent marker. Place them over printed maps to save on reprinting.

The important thing is to match the map to your style of play. There’s no wrong way, only different types of fun.

Final Thoughts: Building Your Battlemap Hoard

Home printing your TTRPG battle-maps is one of those things that starts with frustration (“why is this file 48 inches wide!?”) but ends with enormous satisfaction – especially when your players gasp at the epic spread you lay down.

And you don’t need fancy tools, pricey gear, or even an A3 printer. With a bit of planning, some trimming, and a dose of kobold enthusiasm, you can create table-ready maps on a standard A4 printer.

Remember:

• Seven grid squares per A4 sheet is your baseline
• Use Rasterbator.net for easy tiling
• Scale your maps based on table size, not fantasy
• Always print a small test zone before committing to 16 pages of underdark corridors

With this knowledge, you're ready to level up your maps from “scrap paper sketch” to “cinematic battlefield”.

Bonus Links for the Brave:

• Rasterbator.net – free tiling poster tool
• Photopea.com – browser-based Photoshop alternative
• Posterazor – open-source poster slicer

Until Next Time, Brave GM...

Print boldly. Scale cleverly. And always keep your scissors sharp. Because nothing ruins immersion like a misaligned corridor.

We’d love to see your printed map setups! Tag us on Instagram @thekoboldguild and show off your tabletop conquests.

Now roll a D20 for “Map Assembly Skill Check”... and try not to glue your sleeve to the table.