Overfilling the kettle when we only want one or two cups of tea could be driving up our energy bills.
And although probably not by much, the recent increase in energy prices means that most households are looking for ways to cut down in any way that they can.
One woman was "blown away" as she was filling up the kettle one day while keeping an eye on her energy habits - as she figured out how to make sure she had the right amount of water every time.
The Mirror reports that she could have been saving money all along, thanks to the simple tip.
Posting to TikTok as @buildabundle, mum Anna explained: "Cost of living tip. Who else has just discovered today that the numbers on a kettle don't tell you how many litres of water it holds..."
She continued: "...It actually tells you how many cups of tea that amount of water will make! So you only boil the amount you need. Mind blown! Who else never knew this?! I'm 35," she concluded.
If your kettle doesn't display any numbers on its side, then unfortunately this tip isn't for you.
But, if it does, then you can use this to determine how much water is put in depending on how many cups of tea or coffee you need to make.
While most commenters on the video were already aware of this tip, they were keen to share other money-saving tricks with each other.
One person wrote: "Yup, although they are usually based of a teacup size, if you use a mug just add a 1.5 of their cups," to which the mum replied: "Ahh that’s helpful thank you! I usually fill it half-full and boil loads of water I don’t need, can’t be affording that anymore!"
While a second person said: "same thing with boiling water for rice/eggs etc, you'll use more fuel to heat a bigger pan with more water than is needed."
And someone else advised: "If you’re worried about over boiling water, just microwave the water in a mug. It’s cheaper too." A different commenter questioned: "You really thought your kettle held 8 litres of water?" And the mum admitted: "Yes. Maths isn’t my stronger point!"
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