Free Unit Conversion Calculator 2026 to convert length, weight, temperature, volume, area, speed, and more with fast and accurate results.
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This section explains the mathematical formulas used for common unit conversions.
Length conversion changes a value from one unit to another using fixed ratios.
Formula (meters to kilometers):
Example: 500 meters → kilometers
Weight conversion uses standard mass ratios.
Formula (kilograms to grams):
Example: 2 kg → grams
Temperature conversion uses specific formulas, not fixed ratios.
Formula (Celsius to Fahrenheit):
Example: 25°C → °F
Area conversion scales values based on squared units.
Formula (m² to km²):
Example: 2,000,000 m² → km²
Volume conversion uses cubic unit relationships.
Formula (liters to milliliters):
Example: 3 L → mL
Speed conversion adjusts distance and time units.
Formula (km/h to m/s):
Example: 72 km/h → m/s
Time conversion converts between seconds, minutes, hours, and days.
Formula (hours to minutes):
Example: 2 hours → minutes
Confusing Mass vs Weight
Mass (kg, g) measures amount of matter. Weight (lb, N) measures gravitational force. Use the correct category for your application.
Mixing Metric and Imperial Units
Always convert all measurements to the same system before calculations. Mixing systems causes errors in engineering and construction.
Temperature Scale Confusion
Celsius and Fahrenheit are not linear conversions. Use °F = (°C × 9/5) + 32, not simple multiplication. Kelvin starts at absolute zero.
Rounding Too Early
Always keep full precision during intermediate calculations. Round only the final result to avoid accumulated errors.
All unit conversion factors are verified using internationally accepted measurement standards from NIST (National Institute of Standards and Technology) and ISO unit definitions.
Calculations provide numerical precision up to 6 decimal places, suitable for engineering, scientific, academic, and financial applications.
Reviewed and maintained by the VIP Calculator Engineering Team. Our methodology focuses on accuracy, reliability, and adherence to international measurement standards.
Last technical review: December 2025
All calculations are performed locally in your browser. No data is stored or transmitted.
You can convert length (meters, feet, inches), weight (kg, pounds), temperature (Celsius, Fahrenheit), volume (liters, gallons), and many more unit types.
All conversions use standard conversion factors and provide results accurate to multiple decimal places.
Yes, the calculator supports conversions between metric, imperial, and US customary units.
The calculator can handle very large and very small numbers, making it suitable for both everyday and scientific use.