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Everyday Conversion Formulas

The exact conversion factors for the most common US ↔ metric pairs, pulled from the same NIST / SI constants used by every UnitFig converter. Bookmark it, print it, or paste it into your study notes.

Pounds to kilograms

1 lb = 0.45359237 kg

Example: 150 lb = 68.039 kg (exact factor)

Kilograms to pounds

1 kg = 2.2046226218 lb

Example: 70 kg = 154.32 lb

Feet to meters

1 ft = 0.3048 m

Example: 10 ft = 3.048 m (exact)

Inches to centimeters

1 in = 2.54 cm

Example: 1 inch = exactly 2.54 cm

Miles to kilometers

1 mi = 1.609344 km

Example: 5 miles = 8.047 km (exact)

US gallons to liters

1 US gal = 3.785411784 L

Example: 1 gallon = 3.785 L; 1 liter ≈ 0.264 US gal

US cups to milliliters

1 US cup = 236.5882365 mL

Example: 1 cup = 236.6 mL; 1 mL ≈ 0.004227 cup

mph to km/h

km/h

1 mph = 1.609344 km/h

Example: 60 mph = 96.56 km/h

Square feet to square meters

m²

1 sq ft = 0.09290304 m²

Example: 500 sq ft = 46.45 m²

Horsepower to kilowatts

1 hp = 0.745699872 kW

Example: 200 hp = 149.14 kW

PSI to bar

bar

1 psi = 0.0689475729 bar

Example: 35 psi = 2.41 bar

Binary data

binary units

1 GiB = 1,024 MiB

Example: 8 GiB = 8,192 MiB (binary); decimal 1 GB = 1,000 MB

Practice the conversion too

These examples convert US customary to metric using the exact NIST / SI constants. Open a converter to check any value:

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Frequently Asked Questions

Are these conversion factors exact or rounded?

Every factor on this sheet is the exact internationally agreed constant (e.g. 1 lb = 0.45359237 kg, 1 in = 2.54 cm). Results shown are rounded for readability; the underlying constants are exact.

How do I remember which way to multiply?

Check the units: to go from a smaller unit to a larger one, divide; larger to smaller, multiply. 1 mile = 1.609 km (mile is larger, so 5 mi × 1.609 = 8.045 km).

Is a US gallon the same as a UK gallon?

No. US liquid gallon = 3.785 L; UK imperial gallon ≈ 4.546 L. These sheets use US units, matching everyday American life.

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Last Updated 2026 | Formulas are standard textbook content; conversion constants trace to NIST SP 330 & the BIPM SI Brochure.