Convert between length, weight, temperature, volume, area, speed, and digital storage units. Supports metric, imperial, and US customary systems with instant results.
| Unit | Value |
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Whether you are cooking with a recipe from another country, traveling, shopping online from international stores, or working on technical projects, unit conversion is a daily necessity. This guide covers the most common conversions, mental math shortcuts, and why the world uses different systems.
| Conversion | Quick Rule | Example |
|---|---|---|
| km → miles | × 0.6 | 100 km ≈ 60 miles |
| kg → pounds | × 2.2 | 70 kg ≈ 154 lbs |
| °C → °F | ×2 + 30 | 25°C ≈ 80°F |
| liters → gallons | ÷ 4 | 20 L ≈ 5 gal |
| cm → inches | ÷ 2.5 | 10 cm ≈ 4 in |
Scenario 1: International Recipe. A British recipe calls for 200g flour, 150ml milk, and an oven at 180°C. Converting for a US kitchen: flour = 7.05 oz, milk = 0.63 cups, oven = 356°F. Our converter handles all three in seconds.
Scenario 2: Travel Distance. Maria is driving in the US where signs show miles. Her rental car shows km/h. The speed limit is 65 mph = 104.6 km/h. Distance to her hotel: 120 miles = 193 km. Use our Fuel Cost Calculator for trip cost.
Scenario 3: Online Shopping. David orders a desk from a US site: 60 x 30 inches. His room measurement is in cm. The desk is 152.4 x 76.2 cm. It fits his 160 cm wall space with 7.6 cm to spare.
Scenario 4: Fitness Tracking. Priya’s US-based running app shows miles, but she thinks in km. Her 5-mile run = 8.05 km. Her pace of 9:30/mile = 5:54/km. Her weight of 132 lbs = 59.9 kg for the BMI calculator. Use our Running Pace Calculator for detailed conversions.
💡 Key insight: The most useful mental conversion tricks are approximations. You do not need exact numbers in daily life. km × 0.6 = miles (off by 0.8%). kg × 2.2 = lbs (exact). °C × 2 + 30 = °F (off by 1-3°). Master these three and you will never feel lost in any unit system.
| 1 mile | 1.609 km |
| 1 pound | 0.454 kg |
| 1 gallon | 3.785 L |
| 1 inch | 2.54 cm |
| 1 acre | 4,047 m² |