It measures to 0.01 grams, BUT has a margin of error of plus/minus 0.02 grams, so when something measures 0.15 gram, it could actually be anywhere from 0.13 to 0.17 - when used for medications, that 0.13 to 0.17 could be the difference between not quite enough and a little too much. Don't like that.

This is most problematic when adding material slowly. I will start with an amount, then add a little, and add a little, and add a little and the reported weight does not change. Then I take the cup off, and put it back on, the BAM, now I have too much.

Also, and this is REALLY annoying - it goes off after 1 minute of use. When it turns back on, it does not remember the weight of my measuring cup. Which means I have to dump every thing out, put the cup back on, zero it out, and start over. There is no way to change the 1 minute time.

But it gets two stars instead of one because it DOES measure things.

The scale wasn't "calibrated at the factory," and if it was, who and what they used to calibrate it, I cannot figure out. I got this to measure out quantities of (CENSORED), and it's not capable of doing that, or just about anything else. I opened it up, turned it on, it rested at "0." Then, within a second or two, it went to 0.04, then to 0, then to 0.04, over and over and over. I read the instructions to calibrate it and put it in calibration mode, I read somewhere that a nickel is 5 grams exactly. I don't have calibration weights so I decided to measure 100g in nickels and pennies. I had 12 nickels (5x12=60), and 16 pennies (2.5x16=40). Within putting JUST THREE nickels on it, the calibration weight that was supposed to measure fully at 100g started to say "overload" (or rather, "O-LD") Overload at 15 grams? When I turned it off and back on and rested a single nickel on it, I got 12.6 grams, which fluctuated by ~.4 grams up and down. Flatout, it doesn't work.

Actually I bought it 6 years, 11 months, and 21 days ago...I may as well be exact as this scale...Back then it cost $16.35 + $5.58 shipping since I didn't have Prime yet...I'd gladly pay the same amount for another one, but this one still functions as if it was brand new...

Some reasons why this is a kickass scale, whether old or new :

-The blue backlighting is a discrete convenience...
-Two AAA batteries last a very long time...
-Even if it DID eat batteries, the chamber in back holds a spare set...
-If I didn't know how to use it, all I'd have to do is look at the lid/tray...
-Still accurate to within 1/100 of a gram, according to my other scales...
-Fits in a jeans pocket no problem, and goes wherever I go...
-Doesn't need constant calibration...(Haven't calibrated it this YEAR, but it's still dead on)
-Tare function comes in very handy when weighing hundreds of pills at once...
-Didn't cost much, so I don't really care if it gets a bit banged around...
-The fact that it CAN get banged around...

A few things I've learned :

-It must be on a flat, stable surface or it won't read right...
-The heavier you can make that surface the better, even if it's just a large book...
-To get the best accuracy, press down a little (as lightly as possible) when placing on whatever you are weighing...Don't know why this works, but it does...
-Adjust the position so that the majority of the mass is resting on the center of the weighing platform...
-To clean, breathe on the metal and wipe with something that won't leave traces, such as a shop rag, eyeglass cloth, etc. while the scale is off...I usually do this a few times...
-A bill from your wallet should weigh exactly 1 gram, and makes for a quick tray with plenty of shape options...A fast tool...

Difficult to go wrong with AWS...Employ common sense and it works fine...

HIGHLY RECOMMENDED

Hopes this helps...

GOOD LUCK !!!

I bought this scale in April and have only used it a total of 3 or 4 times. It's kept in it's original box, sitting on my desk. It hasn't been dropped or mistreated. It's never even left my office. Today I tried to use it and it says "FULL". I tried replacing the batteries and the display still reads "FULL". So I google AWS 100 and google suggests "AWS 100 Reads Full". I select that because apparently others have Googled the same issue. All I found was tons of people with the same story as mine and no solution. I tried to reset the scale per directions and that didn't work. I guess you get what you pay for. Do yourself a favor and don't waste your money. Update - I called AWS and they said it can't be fixed, it needs to be sent back on warranty. I pay the shipping and they will send a new one. The guy who answered my call sounded like he was at home. The background noise, kitchen cabinets being shut and then he yawned into the phone and told me he had to go log into his computer. He said he would send me an email to return it. I never got the email so I now have to call back.

I actually ordered 2 scales. One to keep at my place and one for my girls house. Both scales are manufactured by America Weigh Scales. I needed a portable digital scale to help me manage my meal time, caloric intake, because of diabetes. The scales digital readout is mounted on the side of the scale and actually is only open when using the device. The AWS scale has all the bells and whistles of a weighing device that easily costs 3-4 times as much. The new scale has possibly, the most easy, self-intuitive, curve there is for learning the scales features, controls, and various functions. It has 4 modes for weighing. It weighs (g)grams, (oz)ounces, (ct)carats and (gn)grains. Just tap the mode button to switch between measurement units. The scale has a very nice 2 piece, plastic case to protect the scale when not in use. The 2 pieces of the case consists of 1 large base and a smaller sized lid, which can both be used to weigh with.There's also a tare button, which takes and automatically subtracts the weight of your weighing container so your a measurements are precise and exact. You put your container on the powered up scale tray. The backlit display shows the weight of your measuring container. Just tap the tare button again, the display will now read 0.00, you're now ready to add your desired item to be weighed, onto the weighing container. Your scale has a +/- tolerance of 0.02 g. It's well constructed and has a 10 year warranty. By the way, it's powered by 2 AAA batteries. I will gladly recommend this wholeheartily to you, my family and friends.