There are times when I rely on the nanodrop (that I use for Yeast/E. coli measurements) to measure DNA amounts. The machine tells me concentrations in terms of ng/ul but that number is useless most of the time so Steve created this concentration converter that will turn ng/ul into molarity (M) depending on the length of the DNA sequence being analyzed. I’m now sharing this calculator with you all. Public editing is turned on, and you should be able to create your own copy in Google Docs. Otherwise, just edit the DNA length (column labeled “length of ds”) and the concentration (column labeled “mass conc.”) and the third column will show you the concentration in nM.