Unit Conversion in Go
Convert units in Go using dimensional analysis, custom types, and the golang.org/x/text package.
Published:
Tags: unit conversion Go programming, Go unit converter, Golang measurement conversion
Unit Conversion in Go Go's strong typing and zero-overhead custom types make it well-suited for unit conversion code where dimensional correctness matters. With a few patterns, you can catch unit errors at compile time. --- The Base Unit Pattern The most maintainable approach for any-to-any unit conversion: convert to a canonical base unit, then convert from base to the target. This reduces units from needing direct conversion functions to functions. Type-Safe Units with Custom Types Go's type system prevents accidentally mixing units when you define them as distinct types: Temperature Conversion (With Offset) Temperature is a special case because it uses an additive offset, not just a multiplicative factor: Parsing Unit Strings A common need is parsing strings like "10.5 km" into a value…
Frequently Asked Questions
How do I implement unit conversion in Go?
The standard Go pattern: define a custom numeric type for each unit (type Kilogram float64), write convert-to-base and convert-from-base functions, and compose them. For a length converter: func ToMetres(v float64, from Unit) float64 and func FromMetres(v float64, to Unit) float64. Call ToMetres first, then FromMetres to get any-to-any conversion.
What Go libraries handle unit conversion?
Key options: gonum.org/v1/unit (part of Gonum scientific computing suite, type-safe SI units), github.com/bcicen/go-units (flexible unit graph with ~100 built-in units), and github.com/martinlindhe/unit (simple, dependency-free conversion library). For locale-aware number formatting, golang.org/x/text/message is the standard.
How do I use custom types for unit safety in Go?
Define distinct types: type Metre float64 and type Foot float64. Assign them as different types so Go's type system prevents you from accidentally adding metres to feet. Write explicit conversion functions: func MetreToFoot(m Metre) Foot { return Foot(m * 3.28084) }. The compiler will reject Foot + Metre without an explicit call.
How do I parse unit strings in Go?
Use strings.Fields or a regex to split a string like '10.5 km' into value ('10.5') and unit ('km'). Parse the value with strconv.ParseFloat. Use a map[string]float64 of conversion factors keyed by unit string. Handle case-insensitivity with strings.ToLower and common aliases (e.g., 'kilometre', 'kilometer', 'km' all mapping to the same factor).
What is dimensional analysis in Go?
Dimensional analysis in Go means tracking units through your program as first-class type information. If Temperature and Duration are distinct types, you can't accidentally divide temperature by temperature when you meant to divide distance by time. Libraries like gonum.org/v1/unit use struct embedding and method chains to enforce dimensional correctness at compile time.
All articles · theproductguy.in