OneConvert - OneConvert - fast online calculator and free file converter. Allows to convert different file formats and allows quick and accurate conversion between many units of measure.
SpeedCrunch - SpeedCrunch. SpeedCrunch is a high-precision scientific calculator featuring a fast, keyboard-driven user interface. It is free and open-source software, licensed under the GPL. Download Documentation Donate .
iLovePDF - Free online PDF tool set
Qalculate! - Qalculate! is a multiplatform multi-purpose desktop calculator.
Material Unit Converter - Quick, free, online unit converter that converts common units of measurement, along with 77 other converters covering an assortment of units.
Numi App - Numi is a beautiful text calculator for Mac.