Weigh some things you know the exact weight of like 1L of water or your phone (you can google most phones weights, without the case and only if you dont have a screen protector of course).
I had the same issue at home but realized my scale was jus off most of the time.
If your scale is 0.01g precise, just measure a coin. Everyone has them and they have really exact weight (down to the .01g).
I imagine this varies a lot on which country you're in. In the US, coins seem to be mostly toleranced at around 3-5%, but you could probably get away with a large number of coins in good condition from different years.
Scales that go to 0.01g can't weigh 400g. Or at least not with the same precision. At 0.01g you definitely need to calibrate the thing to local gravity and, depending on your geology and whatnot, insulate it against vibrations. Weighing stuff gets crazy fast when it comes to accuracy though 0.01g isn't yet in "hold your breath" territory.
Generally speaking if your scales don't come with a spec sheet don't trust the number of digits. And I've never seen a spec sheet for a kitchen scale that wasn't from G&G, a manufacturer of professional scales that happens to build kitchen scales with left-over sensors not making the cut for the professional series. Their top consumer model does 0.1g from 0-3kg, 1g up to 15kg, forget about weighing spices or such with any other scale with that kind of range you need a second much smaller one. 55 Euro, doesn't like rechargeable batteries but can run off a wall plug and you can also solder on the data port that's missing it will spit out measurements over it just like the professional ones. Oh: LED display. As in not LCD. Green on black, actually readable. In a sense it's worth the money just for that.
I think you're thinking about 0.001g scales. Those are definitely sensitive to air currents and whatnot. But 0.01g scales are relatively cheap to get, and surprisingly accurate for the price! Maybe not down to the .01g exactly but close enough.
But yeah you don't want to use one of those to weigh 400g :P
Weigh some things you know the exact weight of like 1L of water or your phone (you can google most phones weights, without the case and only if you dont have a screen protector of course). I had the same issue at home but realized my scale was jus off most of the time.
If your scale is 0.01g precise, just measure a coin. Everyone has them and they have really exact weight (down to the .01g).
I imagine this varies a lot on which country you're in. In the US, coins seem to be mostly toleranced at around 3-5%, but you could probably get away with a large number of coins in good condition from different years.
Scales that go to 0.01g can't weigh 400g. Or at least not with the same precision. At 0.01g you definitely need to calibrate the thing to local gravity and, depending on your geology and whatnot, insulate it against vibrations. Weighing stuff gets crazy fast when it comes to accuracy though 0.01g isn't yet in "hold your breath" territory.
Generally speaking if your scales don't come with a spec sheet don't trust the number of digits. And I've never seen a spec sheet for a kitchen scale that wasn't from G&G, a manufacturer of professional scales that happens to build kitchen scales with left-over sensors not making the cut for the professional series. Their top consumer model does 0.1g from 0-3kg, 1g up to 15kg, forget about weighing spices or such with any other scale with that kind of range you need a second much smaller one. 55 Euro, doesn't like rechargeable batteries but can run off a wall plug and you can also solder on the data port that's missing it will spit out measurements over it just like the professional ones. Oh: LED display. As in not LCD. Green on black, actually readable. In a sense it's worth the money just for that.
I think you're thinking about 0.001g scales. Those are definitely sensitive to air currents and whatnot. But 0.01g scales are relatively cheap to get, and surprisingly accurate for the price! Maybe not down to the .01g exactly but close enough.
But yeah you don't want to use one of those to weigh 400g :P