Digital Vs traditional scale discrepancies

I have an unusual problem. Although, it might be more usual than I think. I’ve been using a Garmin index scale for several years now with no problems. However I jumped on the traditional health-o-meter manual scale at the gym and got a 6 lb difference… To the lighter side. To be clear the two weights were taken within 20 minutes of each other. I checked the scale at the gym by putting a 50 lb dumbbell on it and it showed 50 lbs on the dot. Thinking my Garmin index might be wrong I put a 25 lb kettlebell on it and it read 25 lbs on the dot. So, as far as I can tell both scales are accurate with a known weight but they both give me different readings on my own body weight by 6 lbs.
To make it more interesting I was actually wearing more clothing on the manual scale at the gym, shoes etc.
What gives?

a Gravitational Anomaly ? 6Lbs. = what percent of total weight ? in my case it would be something like just under 3%

I have always treated scales as N=1 even though they may be calibrated etc. they never seem to agree so I always just use the same scale for tracking etc. and treat others as a general check

About 3%.
I would expect the manual one at the gym to be the more accurate of the two.

The weights you used may not be “accurate” to the claimed value. Without verifying on a more accurate and calibrated scale, I’d avoid putting too much faith in the claimed weights.

As such, you should use the same exact weight on both scales if at all possible. That’s the only real way to have a decent comparison.


Yes, that was my first thought too. Dumbbell weights can vary a lot. As can plates. Calibrated plates cost hundreds of dollars for just a single pair, so almost no commercial gyms use them…