Checking Whether Your Scale Is Telling the Truth

Kitchen scales are trusted implicitly and almost never verified. Checking one takes five minutes and occasionally reveals something worth knowing.

When to Check

When a scale is new, after it has been dropped, after a battery change, if results have started going wrong for no obvious reason, and once a year as a matter of routine.

Also after any move between very different temperatures, since the load cell needs to equalise before it reads correctly.

What to Check With

• Calibration weights, which are inexpensive and are the proper answer
• Coins, which have published specified masses
• Water, since a litre at room temperature is very close to a kilogram
• Anything with a printed net weight, as a rough check only
• The same object repeatedly, to test consistency rather than accuracy

Where a manufacturer states a tolerance for a model, of the kind published in escali scale specifications, that figure is what a result should be judged against rather than an assumption of perfection.

Check at Two Points

The step most people skip. A scale can be correct at 500 grams and noticeably off at 50 grams, or the reverse.

Testing a light load and a heavy one reveals whether the error is a fixed offset or a proportional one, which are different problems.

Test the Corners

Place the same weight at the centre and then at each corner of the platform.

Significant differences mean either the surface is uneven, the feet are dirty or damaged, or the load cell mounting has been disturbed. This is a common and easily fixed cause of inconsistent results.

The Surface Matters

A scale needs a hard, flat, level surface. A worktop with a seam under one foot, a tablecloth, or a slightly warped chopping board all distort the reading.

This is the single most common cause of a scale that seems to have gone wrong, and moving it resolves it.

Batteries

Low batteries produce erratic and drifting readings before the low-battery indicator appears.

Any scale behaving oddly should have fresh batteries before anything else is concluded. Mixing old and new cells causes the same problem.

What Consistency Really Means

For cooking, a scale that reads two per cent high consistently is entirely usable, because every ingredient is scaled by the same factor and the ratios hold.

A scale that reads differently each time is not usable, however close its average is to correct.

When It Cannot Be Fixed

A scale that has been overloaded may have a permanently deformed load cell, which no recalibration corrects.

Standing on a kitchen scale is the usual cause, and the damage is invisible.