chemCal is a basic chemistry concentration (molarity, moles per liter) and dilutions calculator for students of chemistry, biology, biochemistry, and biomedical sciences at school, college or university. The calculator is easy to use, just input the concentrations (Molar, mM etc.), molecular weights, percentages, and dilutions (liters) you wish to use, and you get the answer. The calculator can also easily and quickly convert between different unit values such as milli (m), micro (μ), nano (n), pico (p) and femto (f).