Why magnet size matters
Magnetizing your minis only works if the magnet is the right size for the base. Too small and a model won't hold to the sheet — especially a tall or heavy one. Too large and it won't fit a small base, grips so hard you can't lift the figure cleanly, or costs more than it needs to. The goal is a magnet that centers neatly under the base and holds the model firmly upright when the box is tilted, but still lets you pluck it off the sheet without a fight.
The sweet spot most hobbyists use
Across countless setups, the size that keeps coming up is a neodymium disc around 5x2mm — that's roughly 5mm across and 2mm thick. It's strong enough to hold an infantry model firmly on a receptive sheet, but not so strong it's a nuisance to pull off, yanks itself out of the glue, or makes models cling to each other. Nearby sizes like 4x3mm, 5x1.5mm, and 3x2mm all work in the same range. Bigger magnets (say 10x2mm) give more glue surface but are overkill for most models and just add cost and cling. Use neodymium (rare-earth) discs; weaker magnet types won't hold reliably.
Magnet size by base diameter
A practical starting point, matching common round base sizes to disc magnet diameter. Step up a size for tall or metal models.
- Small bases (around 25mm): a roughly 5mm disc (the 5x2mm sweet spot) centers neatly and holds light infantry.
- Medium bases (around 32mm): 5–6mm still works well; step up slightly for taller models.
- Large bases (40mm and up): a 6–8mm disc, or two magnets, for the extra weight and leverage.
- Very large or heavy models: multiple magnets spread across the base, since tall figures tip more easily.
Weight and height change the answer
Base size is the starting point, but model weight and height decide the final magnet. A light plastic trooper on a small base holds with a tiny magnet; a heavy metal character or a tall, top-weighted model on the same base needs more pull or it'll flop over when the box tilts. When in doubt, go a little stronger — a magnet that's slightly too strong just grips firmly, while one that's too weak fails exactly when you need it, in transit. For very tall models, spreading two magnets across the base beats one oversized one.
One reason not to go too strong
There's a real downside to oversized magnets beyond cost. If every base carries a powerful magnet, adjacent models on the table or in a tray start sticking to and repelling each other — annoying to separate and, with fragile parts, sometimes damaging. This is one argument for the modest 5x2mm size, and for the washer-in-base approach: put a steel washer in the base and magnetize only the storage sheet, so models grip the box but stay neutral toward each other.
Special cases: clear and flight bases
Not every base is a solid disc. Clear flying bases and large oval bases don't give you a neat spot to sink a small magnet, and a tiny disc lost in the middle of a wide base won't hold a top-heavy winged model. For those, a larger flat sticky magnet sized closer to the base — around 32mm for a big round flight base — spreads the hold across the whole footprint so the model doesn't pivot. The principle is the same as everywhere else: enough contact area and pull to keep the model planted, without going so strong that removal becomes a wrestling match.
Thickness, fit, and consistency
Magnet thickness matters as much as diameter. Too thick and it lifts the base off the ground so the mini wobbles; too thin and it may not reach a recessed base bottom. Aim for flush or slightly recessed — around 2mm is the reason the 5x2mm disc is so popular. Finally, keep your whole collection consistent: same size, same orientation on every base, so every mini is compatible with every magnetic box you own. Buy an assortment if you mix small troopers and large characters, and let glue cure fully before storing — a magnet that pops off in transit undoes the whole point of magnetizing.