Are these converters accurate?

Yes. SwiftTooly uses well-known conversion factors (e.g. 1 in = 25.4 mm exactly, 1 lb = 0.453592 kg) verified against international standards.

Do I need an account?

No. Every converter runs in your browser with no sign-up, no upload and no logging of the values you type.

Unit Conversion Tools

Pre-set converters for the most common unit pairs — each with the formula, a quick-reference table and a working converter. Or use the full Unit Converter for any pair.

Length

Kilometers → Miles Miles → Kilometers Centimeters → Inches Inches → Centimeters Meters → Feet Feet → Meters Millimeters → Inches Inches → Millimeters Yards → Meters Meters → Yards

Weight / Mass

Kilograms → Pounds Pounds → Kilograms Grams → Ounces Ounces → Grams Kilograms → Stones Stones → Kilograms

Temperature

Celsius → Fahrenheit Fahrenheit → Celsius Celsius → Kelvin Kelvin → Celsius

Volume

Liters → Gallons (US)Gallons (US) → Liters Milliliters → Fluid ounces (US)Fluid ounces (US) → Milliliters Cups (US) → Milliliters Milliliters → Cups (US)

Speed

Miles per hour → Kilometers per hour Kilometers per hour → Miles per hour

Data Storage

Megabytes → Gigabytes Gigabytes → Megabytes Kilobytes → Megabytes