Inaccurate Data
In this article
Start here
The Core measures your weight. Everything else on the screen is estimated from that weight, an electrical signal passed through your body, and the height, age and sex in your profile. Estimates move around more than measurements do, which is why the trend over weeks matters more than any single morning.
This covers the Voltra Core. If the readings aren't reaching the app at all, see syncing problems instead.
What's measured and what's estimated
| Reading | Where it comes from |
|---|---|
| Weight | Measured directly by the scaleThe only figure taken by measurement alone |
| BMI | Calculated from your weight and the height in your profileArithmetic, not a measurement |
| Body fat, muscle mass, body water | Estimated from the electrical signal, your weight and your profileHold the handle or these won't be produced at all |
| Visceral fat, bone mass, metabolic rate | Estimated the same wayThese move least day to day, so a sudden jump usually means a poor reading rather than a real change |
None of this is a clinical measurement, and it isn't intended to be. It's built to show you which direction you're heading in.
Weigh yourself the same way every time
Most complaints about accuracy are really about inconsistency. Do these five things and the numbers settle down.
- Same time of day. First thing in the morning is best.
- After the toilet, before food and drink. A large glass of water is about half a kilo on its own.
- Bare feet and bare hands. Socks block the signal entirely.
- Hard floor, same spot. Carpet, rugs and uneven tiles all change the reading. Mark the spot if you have to.
- Stand still. Feet evenly placed, weight balanced, no leaning on anything, until the display stops changing.
Why your weight moves day to day
Two or three pounds of movement between mornings is completely normal and is almost entirely water and food, not fat. Common causes:
- Salty food the night before, which holds water for a day or two
- A hard workout, which can hold water while muscles recover
- Alcohol, which shows up as a drop first and a rise after
- Where you are in your menstrual cycle
- Illness, travel and poor sleep
- Simply not having been to the toilet yet
Look at the weekly average in the app rather than this morning against yesterday morning. Fat is gained and lost slowly, so anything that appears overnight isn't it.
Why body composition moves more than weight
The signal the scale uses travels through water, so anything that changes how hydrated you are changes the estimate. Dehydrated in the morning, body fat reads higher. Straight after a drink, it reads lower. Neither is your body changing within the hour.
That's why it's worth weighing in under the same conditions every time. You're not chasing a true number - you're making the readings comparable to each other so the trend means something.
Check your profile first
If your body composition figures look wildly wrong rather than slightly off, this is usually why. The estimates are built on the height, date of birth and sex in your profile, so a height entered in the wrong units, or a date of birth that's out by decades, will throw everything.
Check it under Mine, then Account information. If you share the scale, check the profile you're weighing against is actually yours - a reading taken under someone else's profile is calculated with their details.
It doesn't match my gym scale, or a body scan
It won't, and that's expected. Every scale and every scanner uses its own formula, and the same person weighed on three devices in one afternoon will get three different body fat figures. A hydrostatic tank, a DEXA scan and a bathroom scale are three different methods measuring different things.
Pick one device and stay with it. A number that falls steadily on your own scale is telling you something real, even if a different scale would put it two points higher.
Calibrating the scale
The Core zeroes itself, but it needs a moment to do it after being moved.
- Put it on a hard, level floor where it's going to live.
- Step on briefly and step off again. This wakes it and lets it settle on the surface.
- Wait for the display to clear, then weigh yourself as normal.
Do this any time the scale has been picked up, leaned against a wall or stored somewhere. Weighing on a scale that's just been moved is the most common cause of a reading that's out by a noticeable amount.
The weight is obviously wrong
A few kilos of drift is conditions. Tens of kilos, or a number that jumps around between consecutive readings, is a fault or a setup problem.
- Move it onto a hard floor and re-zero it using the steps above.
- Check nothing is under one corner - a bath mat edge or a loose tile is enough.
- Charge it. A very low battery can produce odd readings before it stops working altogether.
- Weigh a known object, like an unopened bag of sugar or a set of dumbbells, and see whether the figure is right.
If it fails the known-object test, it's a hardware fault, and it's covered by your warranty.
Still not right
Message us with your order number, what the scale is showing, what you'd expect it to show, and the floor surface it's standing on. If you've done the known-object test, tell us that result too - it's the quickest way for us to tell a faulty scale from a conditions problem.
Was this article helpful?