Once every couple of weeks, I see someone ask about using 1:72 scaled miniatures along with their 28mm miniatures.
This isn’t a dumb question: I’ve certainly asked it myself, there’s a plethora of inexpensive 1:72 stuff out there, and 28mm is kind of a weird, messy scale that doesn’t have a convenient 1:something ratio and is often accompanied by freakish, unusual proportions.
1:72 is a fine scale (I find it unsatisfying from a hobby perspective, but I’ve been convinced that from a gaming perspective it’s the greatest of scales), but it is wildly out of whack with 28mm miniatures.
As you can see: the 1:72 scale miniature is about half as tall as a 28mm scaled miniature. They simply are not even close. The only scenario in which one might want to mix the two scales would be if they wanted to use the 1:72 figures as halflings.
If you’re looking for something you can use with 28mm figures, look instead for something between 1:43 and 1:56 or O scale.
Bolt Action is good proof of this: Warlord’s figures are 28mm and their vehicles are Italeri 1:56 models. To my tastes, I find the vehicles on the small side, but some of that is caused by Warlord’s heroic scale proportions (the pumpkin-sized heads and baseball mitt-sized gloves I prefer).
The tank on the left is a 1:56 Company B Sherman Tank, with a Warlord/Italeria tank driver sticking out of the the bop. Compare the size on the head of the tank driver (1:56) to the 28mm Warlord Marines. The car on the right is a 1:43 Greenlight Fast & Furious Dodge Charger.
When it came time to buy some trucks for my Bolt Action French Resistance, I picked up some Welly/Ledo models: the one on the left is (I believe) a 1:64 Ledo Days Gone truck and the one on the right is the same vehicle, but in 1:43 and manufactured by Welly. The former is, clearly, too small, and the latter just right.
I don’t have any 1:72 cars or tanks, but I believe this is a 1:72 Mustang next to a 28mm Warlord Marine. Compare the size of the heads.
So, 1:56 is close enough but on the small side, 1:43 is close enough but on the large side. 1:72 isn’t even close.
I hope this is helpful, and that person who’s trying to math their way into proving that 1:72 is, indeed, close enough to use with 28mm miniatures (there’s always at least one); I’m sure they’re well-intentioned but they don’t know what the hell they’re talking about.