# Large kitchen scale shows very inaccurate results for large masses

I have a three different huge kitchen (?) scales with accuracy / being able to measure stuff to up to 200 kg / 440 lb.

When I compare the results, for first two scales they're:

• comparable or identical (+/- 0 to 0.5 kg) for 0-100 kg range,
• comparable (+/- 0.5 to 1.5 kg) for 100-200 kg range.

When I compare these two scales to the third one then the results are:

• comparable or identical (+/- 0 to 0.5 kg) for 0-100 kg range,
• way not comparable (+/- 6 to 9 kg) for 100-200 kg range.

How can that be? Has anyone ever heard about such situation? I can't say that my third scale is broken or inaccurate, because for 0-100 kg range it measures identical results as two other scales. Only going above 100 kg causes it to go wako.

• Yes you can say it's inaccurate for higher weights, because that's what it is. It's unclear what your question actually is, so long as didn't make a mistake while testing, one of your scales clearly loses accuracy as weight increases. Depending on the technologies used for each scale, it can happen for different reasons.
– eps
Aug 13, 2022 at 17:58
• For example if it uses springs, Hooke's law only applies within certain ranges, and beyond that F ~ x^2 no longer applies
– eps
Aug 13, 2022 at 18:01
• Springs can degrade or deform permanently, electronic components can drift over time, which correlates to error in measurements.
– eps
Aug 13, 2022 at 18:10
• @eps Thanks for trying to answer. I forgot to mention that this is a brand new electronic scale. So neither springs (affected by Hooke's law or by springs degradation) nor electronic components degradation. If that matters. Aug 13, 2022 at 18:50
• Despite this being a kitchen scale, it's not a good question for SA. You really need one of the electronics or DIY SE; answerers who know the internals of scales just don't hang out here. When posting it in another group, include the brand and model of each scale. It's not technically off-topic, so not voting to close, but I really think you'll get better answers elsewhere. Aug 13, 2022 at 19:19