Free Unit Converter
Convert 800+ units across 23 categories with animated visualizations and formula display — a free alternative to Wolfram Alpha. No sign-up required.
Convert between 800+ units across 23 categories — length, weight, temperature, time, plus engineering and scientific units like viscosity, thermal conductivity, and torque. Features animated scale visualizations, the underlying conversion formula displayed inline, batch conversion of multiple values, and a keyboard-first command palette. A free alternative to Wolfram Alpha and ConvertWorld for everyday and specialist conversions.
Built and maintained by James Nicolaus
Engineering & Scientific Units
Go beyond kg-to-lbs — convert viscosity, thermal conductivity, torque, pressure, flow rate, and 18 more categories used by engineers and scientists daily.
Animated Scale Visualizations
See your conversions come alive — thermometers for temperature, balance scales for mass, speedometer gauges for speed, and proportional bars for everything else.
Keyboard-First Workflow
Press Ctrl+K to type natural language like "5 miles to km". Tab through fields, swap units with a keystroke, and batch-convert lists of values.
Instant Formula Display
Every conversion shows the underlying math with syntax-highlighted formulas and animated variable substitution — perfect for students and engineers.
About Free Unit Converter
Free Tool Shed's Unit Converter is a comprehensive conversion tool covering 800+ units across 23 categories — from everyday measurements like length and temperature to specialized engineering units like viscosity, thermal conductivity, and torque. Unlike basic converters, it features animated scale visualizations, real-time formula display, batch conversion, and a keyboard-first command palette.
Solving STEM problems? Pair this with the free graphing calculator for equations and the free interactive periodic table for molar mass, electron configurations, and element properties.
Tips, Mistakes & Takeaways
Tips
- →Pin frequently-used units to favorites — saves scrolling through 800+ entries every time.
- →Use the command palette (Ctrl/Cmd+K) to jump straight to a unit instead of clicking through categories.
- →Batch convert by pasting a column of values — the result column updates in real time.
- →Toggle the inline formula display when you need to show the work, not just the answer.
- →Adjust decimal precision when working with very small or very large numbers — defaults are tuned for everyday use.
Common Mistakes
- !Confusing US gallons with Imperial gallons — they're 3.785 L vs 4.546 L. The category label distinguishes them.
- !Converting between dimensionally non-equivalent units (energy → power) and expecting a result — they're different physical quantities.
- !Trusting locale-specific defaults silently — verify category and unit selection match what you actually mean.
Key Takeaways
- ✓Conversions run client-side — no network round-trip, no rate limits, works offline once cached.
- ✓Covers everyday measurements through specialist engineering units like viscosity, torque, and thermal conductivity.
- ✓Designed for quick lookups and bulk conversions, not symbolic algebra over units.