Can Scales Be Wrong? 8 Reasons Why You Might Not Weigh What You Think

There’s a distinct possibility you’ve internally pondered that question when stepping on the bathroom scales – especially after that all-inclusive to Cancun in 2008. The truth is there’s a number of factors to consider before you start signing yourself up to eat dust for the next 4 weeks, and we’ll cover them in this post so you can be armed with the facts next time you pull out the ‘sad step’.

Can Scales Be Wrong?

There’s no denying that when we know we’ve indulged, it takes some courage to clean off the scales and face the damage – and it’s unlikely we’ll be nicely surprised.  If you’re one of the lucky ones that barely fluctuates an ounce, then you probably know what your comfortable weight sits at without even using scales, and with minimal effort to boot. But then the chances are you didn’t Google and come across this blog post in the first place!  For the other 64% of us, the scales are what we (often mistakenly) define our health by, when usually it is only a small chapter to a much bigger story.

Human nature tells us it’s a number that matters, so, here are some reasons why your scales could be wrong.


  • You don’t weigh yourself consistently

When we say consistently, we’re not just talking about WHEN, but also HOW.

It doesn’t matter what day of the week it is, but remember whatever day you take a starting weight, that should be your unofficial weigh day. Reason being, we’re creatures of habit. 

Do you prepare homemade family dinners and discuss your day at the dining table after school or work weekdays? Do you enjoy a glass of wine (or entire bottle – no one’s judging) at the weekend watching Gogglebox? Does the inevitable hangover mean your midweek granola gets pushed to the back of the cupboard til Monday comes around again? 

If your routine doesn’t change too drastically week on week, then weighing on the same day – even at roughly the same time – can help ensure that the reading you’re getting is as accurate as it can be. If your scales reside in your bathroom, keep them there. Pick a floor tile and make that your weighing spot even. The best time would be first thing in the morning – with an empty stomach and an empty bladder. Your birthday suit weighs consistently the same whilst we’re at it!

If they call home a carpeted surface, or a hard one that isn’t completely level, then the pressure on the corner sensors in a digital set of scales will be uneven, and the reading inaccurate. Move them to a hard surface!

The ever-popular slimming clubs are definitely on to something here – by using the same set of scales in the same location and weighing you on the same day at roughly the same time, they can be sure your weight today is a true comparison to your weight last week. As in any experiment, the smaller the number of variables, the more accurate and reliable the results will be. If you wanted to take it to the extreme, if you’ve ever attended said slimming club, you’ll see there’s a queue for the loo before the queue for the scales. What’s more, you’d be forgiven for thinking that they all only own one outfit, because the seasoned weighers will have a specific outfit, and even perhaps a weigh day meal plan. It may seem excessive but wearing your UGG boots one week and taking your flip flops off for the next can impact your ‘weight’ by as much as 2-3 lbs. 

As much as you can do it too little, you can also do it too often – experts would also say don’t weigh yourself more than once every 7 days, as depending on your diet and lifestyle, the numbers can fluctuate drastically throughout the day as well as the week. 


  • The scales are broken

It might sound like the worst excuse in the book, but it’s completely plausible. If you want to do a basic check to see if your scales are indeed ready for the tip, you can weigh that litre of water we talked about – don’t forget to tare (zero) the scales when the container is still empty so you’re only weighing the water! Then test it a few more times; the repeatability of the scales can be equally as dodgy as the reading and may be another reason why your questioning your trust levels with the scales. 

If either the weight or the repeatability is off and you’re rocking a digital set, try changing out the batteries but some brand-new ones or getting them repaired . If they’re analogue, they could’ve taken a knock which is a lot more fiddly to fix. Perhaps it’s time to join the digital age…?

If you prefer to weigh on one of the coin-op scales you find in pharmacies or Boots, these should be calibrated regularly. The ones in the doctor’s surgery definitely will be!


  • You’ve just inhaled a salty or stodgy meal

Listen, it doesn’t have to be a diet-busting pepperoni pizza with stuffed crust and a whole tub of ice cream to affect the scales – even a veggie packed stir fry could get you chugging liquids like you’re on an Irish stag do if it’s slathered in soy sauce. Your body then stores as much H2O as possible in a bid to combat the jump in sodium levels. In addition, loading up on more refined carbs than your body needs (or is used to) causes the body to store the excess as glycogen in your liver, which attracts water like a sponge as well.


  • You’ve just drank a load of water

If you’re on a mission to lose the lockdown lbs, you’re probably already guzzling water like the tap is about to dry up. But just remember that a litre of water weighs a kilogram (or 2.22 lbs imperial), but don’t worry – water weight is only temporary.


  • You’ve just been to the gym

If you’re weighing yourself after an intense and sweaty session on the treadmill, then be prepared to see a drop on the scales. Woohoo! Oh, but that’s also temporary. Booo. 

As soon as you replenish those lost fluids, your weight will normalise again.


  • You’ve replaced fat for muscle

The old adage “muscle weighs more than fat” is a little misleading – a lb of anything weighs the same as a lb of anything! But it is true that muscle is denser than fat; this means that for the same weight in muscle, you’ll look leaner as it takes up about a third as much space on your bones. So, you’ll have dropped a clothing size or two, but the scales won’t reflect that. Whip out the tape measure and take progress pics!


  • You’re erm…constipated

Remember what we said about the queue for the loos? If you’re a fan of Peter Kay, you’ll know how much lighter you might be after a visit to the toilet. Every little helps!


  • You thought Covid calories didn’t count

We’ve done a lot of unofficial personal chocolate-based research on this subject for over a year and it’s just not true. That would be nice though, wouldn’t it?


So, there are a number of reasons why your bathroom scales might fluctuate throughout the month. Whether it is external factors such as food you have consumed, or something a little more in your control such as your scales being broken. If you find yourself needing calibration, here at GNW we can support your needs, simply call one of our friendly experts on 01704 536010 or email us at and we will get back to you.