OK, not really. But I knew the cheapo IKEA scale in the house we're renting was underestimating my weight. I've been adding 5 pounds to the reading, just as a guess. Today I weighed myself at the gym: turns out our home scale is 15 lbs off, not 5!
So, I have a leeetle further to go than I thought.
But, it's just a number, and it's going in the right direction.
Maybe it's not as far off as you think. If you've been weighing yourself in the morning before you eat or drink anything, and then you weighed yourself in the middle of the afternoon at the gym, your weight could have easily gone up just because of what you've eaten during the day, or that 16 ounces of water you drank while you did your workout or something. Don't get discouraged. Just pick one scale and go by that one! Keep up the great work!
Agreed with others that it may not be as far off as you think -- true, your rented scale may be under-estimating, but it's also VERY possible that the gym scale is over-estimating too (esp. if they aren't frequently maintained, since gym scales tend to take a lot of wear and tear from many folks weighing themselves throughout the day.)
The best thing to do is just pick one scale and weigh yourself on that consistently, so that regardless of how many pounds it's over- or under-estimating, you can still consistently track your weight changes.