Calculators
2 tools in the Units area.
Formula with Units
A unit-aware calculator: type variables with values in any mix of SI and US customary units (kN, lbf, slug, ft/s, deg …), a formula in plain syntax, and the tool evaluates it with the site's symbolic unit engine. Every variable is reduced to the seven SI base units (plus the radian), the formula is checked dimensionally (a force cannot be added to a length, the argument of a sine must be dimensionless), and the result is reconstructed into a derived unit, shown in SI with a sensible prefix, in US customary units, in any requested compatible unit and as its base-unit form. An optional Buckingham Pi analysis gives the dimension matrix of the variable list, its rank, the number of independent dimensionless groups and the groups themselves.
4 worked examples reproduced, listed on the tool page.
Unit Calculator Pad
A multi-line scratch pad for calculations with units: type lines such as F = 12 kN, A = 0.5 in^2, stress = F / A in MPa, L = 3 ft + 4 in or x = sqrt(2 * 9.81 m/s^2 * 10 m), with unit literals anywhere in an expression, comments after #, and later lines using the names defined earlier. Every line is carried in the SI base units with its exponent vector, so a sum of a length and a time, a sine of a force or an unknown unit spelling is refused in words, and the result sheet gives each line in its natural derived unit (N, Pa, J, W, with an SI prefix), in the unit you asked for, in US customary units, in base units and as a dimension vector. A variables table closes the sheet, the unit algebra of every operation can be shown step by step, and the sheet can be copied as text. Conversion factors follow NIST SP 811 (2008) Appendix B; the default pad is a twelve-line worked example (a rod stress, a pipe flow, a kinetic energy, a pressure head and the 60 mi/h = 88 ft/s chain) whose values are the SP 811 ones.
1 worked example reproduced, listed on the tool page.