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Rink is a unit-aware calculator. It can be used for physics and engineering calculations, as well as dimensionality analysis.

Rink supports most systems of measurements including SI, CGS, natural, international customary, US customary, UK customary, as well as historical measurements. In addition, Rink supports currency conversions.

Unique features:

  • High-precision bignum rational arithmetic
  • Detailed error messages
  • Shows SI physical quantities
  • Finds applicable SI derived units automatically
  • Helps with dimensionality analysis, such as by offering unit factorizations and finding units for quantities.
  • Open source
  • First-class support for non-absolute temperature scales

Describes (hopefully) everything you need to know to use Rink's expression language.

Rink is available via a web interface in addition to the terminal-based interface. Useful for doing calculations on mobile.


The most common version of Rink is the command line interface rink.

Package Manager Command
Cargo cargo install rink
Pacman pacman -S rink
Nix nix-env -i rink
Scoop scoop install rink


> kWh/year -> W
0.1140795 watt (power)
> W -> J
Conformance error: 1 watt (power) != 1 joule (energy)
Suggestions: multiply left side by time, multiply right side by frequency
> gallon gasoline -> kWh
approx. 36.63388 kWh (energy)
> googol^100
1.0e10000 (dimensionless)

Library Usage

rink-core = "0.6"


Rink source code is licensed under the Mozilla Public License, version 2. See LICENSE-MPL for details.

The data file definitions.units is licensed under the GNU General Public License, version 3. See LICENSE-GPL for details.


Contribution guide can be found on the wiki:

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work will grant the rights lined out in the MPL, including larger works with secondary licenses.


See here: