We’ve just bought some fruit and vegetables from Coles Edgecliff 2027. we queried the cost of a single lebanese cucumber with the self check out assistant. She weighed the cucumber and came out with the same weight and cost. On returning home we checked our groceries and they all weighed less and so cost us much more! They should check the scales and recalibrate them. How do we know this hasn’t been happening for years!
Welcome to the Community @Christina2
The shops are legally obliged to have their scales checked for accuracy. Two returning the same weight and both equally out of calibration would be surprising even if not impossible.
For comparison and clarity, has your home scale been calibrated and is known accurate? If not, would you let us know if it is electronic (haptic), spring, or weight and balance?
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Hi @Christina2, welcome to the community.
It is assumed the scales in Coles were digital scales and not the old style spring scales with analogue dial.
As outlined by @PhilT, Coles is bound by weights and measures under the National Measurement Institute. Coles would be servicing and calibrating their balances regularly in accordance with NMI requirements.
Home scales aren’t usually serviced and calibrated. Over time their accuracy can wander, and start reading higher or lower. Wandering accuracies isn’t usually an issue for home use.
However, any balance can go out of calibration at any time. An easy way for precision balances is to give them a knock, dropping something onto them or placing something in excess of the design capacity of the balance.
There is a possibility that the Coles balance is weighing incorrectly, but the probability of where the weighing error exist will be with your home scales.
If you are concerned about the risk of a balance being ‘out’, the major supermarkets have calibrated balances in their fruit and vegetable sections. One can check the weight of things in store, and if it is found the weigh is significantly different at the checkout (say more than a couple of percent), then the weight at the checkout can be challenged. Note: one needs to check the balance in store has been tared to zero before placing anything on the balance.
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It’s an electronic kitchen scale. we’ve just weighed some packaged dried goods that indicate the scale is accurate
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Thank you
Just a question: how much was the difference in the weights? What did the cucumber weigh in store and on your kitchen scales?
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I agree your weight should be very close to accurate then as dry goods packets tend to be pretty accurate as points of comparison.
In your situation I would return to the Coles with your goods having disputed weights and have a chat with the manager. Some fresh F&V will change weights over a few days as they age, so worth taking that into consideration - eg do it immediately and do not rely on your photos of the item on your own scale as it would be challenged.
I doubt anything is intentional but it does happen. We always use the local Coles electronic ‘nut scale’ to weigh our F&V and have found the checkout scale is usually +/- a bit, but not so much as to complain about. The Coles F&V scales are spring scales of lesser accuracy. Woolies in contrast has installed electronic scales through their F&V section but there remain minor variations at checkout.
From my own electronic kitchen scale if I weigh the same item multiple times in succession it will vary by as much as 2g. Not much to affect a price very much, unless one is weighing saffron 
It is also possible the attendant cross-checked your questioned weights with a spring scale and used a calculator for all one knows, although one would hope they were trained not to do that and had a reference scale available.
Next time would you go back and let us know how it went?
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