In the US every gas pump I've seen (I have not check the majority of states, but still a good sample) has a sticker on it stating inspections and who runs the state department that inspects them. Usually it is a yearly inspection (at least according to the sticker, maybe they do it more often I don't know)

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Gormo 2 hours ago | parent [-]

Not just gas pumps, but any measuring device used to determine the price of a metered product. The scales at the register at supermarkets also have calibration stickers in my state.

	▲	bluGill 2 hours ago \| parent [-]
		Now that you mention it, I've seen them at some grocery stores - but generally not in a place I'd be looking unlike gas pumps where is is right next to the price and so you won't miss it.