I wrote Avogadros Calculator to make benchwork easy--and now I use it every day. Here's what you can do with it:
-Convert between mass and moles, mass/volume and molarity
-Use a wide range of units (so you never get 0.0000001 mg)
-Easily figure out how to get the concentration you need, no matter the units or volume
-Make serial dilutions when you have a big dilution factor
-Use it to make up solutions, whether you need to know how many grams to use to get 500 mL of a 1 M solution or you just want to make as much 250 nM solution as you can from 10 mg of your compound.
-Determine the number and volume of aliquots you can make.
-Calculate the volumes of each reagent to use in a master mix for the number of wells you need, plus overage.
-Save master mixes, so you can just type it in once, save it, and load it up in the future.
-Send a copy of any calculation by email or to other apps for record-keeping.
-Just type in the chemical formula and it'll determine the molar mass, so you don't have to look it up.
-Free, with no ads! I made it because I wanted to use it.
-Under active development. Request new features at email@example.com