Unit Converter Guide: Convert Length, Weight, Temperature & Measurements
A unit converter transforms values across SI and US customary systems and many specialized categories (speed, energy, pressure, data). It preserves precision internally and rounds results for clear presentation.
What is Unit Converter?
The unit converter uses dimensionally consistent factors and affine formulas (for temperature) to convert between units like meters ↔ feet, liters ↔ gallons, joules ↔ BTU, and bytes ↔ bits/kilobytes.
How to Use the Unit Converter
- Choose a category (length, mass, volume, temperature, etc.).
- Enter a value and select from and to units.
- Convert to see the result with appropriate significant figures.
- Chain conversions (e.g., cm → in → ft) if desired; the tool keeps precision.
- Create custom units by defining a scale relative to a base unit.
Formulas & Methods
- Multiplicative conversions:
x_to = x_from * k(e.g.,1 in = 2.54 cm). - Temperature (affine):
C = (F - 32)*5/9;F = C*9/5 + 32;K = C + 273.15. - Compound units: derive from base units (e.g.,
1 N = 1 kg*m/s^2). - Data: distinguish decimal (kB=1000 B) and binary (KiB=1024 B) prefixes.
- Precision: carry extra digits internally and round to display with sensible sig figs.
Assumptions & limitations
- Some legacy US units (dry vs liquid gallon) vary; select the correct variant.
- Display rounding differs by context; engineering uses sig figs, finance uses decimal places.
- Conversions assume constant factors; real-world conditions (e.g., gas volume vs temperature) require separate models.
Examples
Example A — Length
72 in -> = 182.88 cm or = 6 ft.
Example B — Temperature
75 F -> 23.888... C -> 23.9 C (1 decimal).
Example C — Data
10 MB (decimal) = 10,000,000 B. In binary, MiB -> 9.54 MiB.
| Category | From | To | Result | |---|---|---|---| | Speed | 60 mph | km/h | 96.5606 | | Volume | 3 L | gal (US) | 0.7925 | | Pressure | 101.325 kPa | atm | 1.0 |
Pro Tips & Best Practices
- Keep units consistent within a calculation before converting final results.
- For temperature, remember offsets; do not treat like multiplicative conversions.
- Use binary prefixes for computing; decimal for storage marketing.
- Round once at the end; keep guard digits during calculation.
- Label outputs with units to avoid ambiguity.
Related Calculators
FAQ
Q: Which units can I convert?
A: Common categories include length, area, volume, mass, temperature, speed, energy, pressure, and data units.
Q: How do I avoid rounding errors?
A: Convert using full precision internally, then round for display; keep consistent significant figures.
Q: What is the difference between SI and US customary units?
A: SI is the metric system (meters, kilograms); US customary includes inches, feet, pounds, gallons.
Q: How do temperature conversions work?
A: They are affine (involve scaling and offset): C = (F - 32)*5/9 and K = C + 273.15.
Q: Can I make a custom unit?
A: Yes—define a unit scale relative to a base unit to create custom conversions.
Call to Action
Pick a category, choose units, and convert precisely—use sensible rounding and clear labels for professional results.