My thermometer is from a restaurant-supply company, and it can be calibrated. I haven't done it yet, though... But, the directions to calibrate say to fill a glass with half ice and half water, and you want the thermometer to read 32*. You could check yours and see if they do that. If they don't go that low, water boils at 212*, so you could take the temp of boiling water too. If you've got that many, you can figure which one is most accurate. Just a thought!