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Mastering Unit Conversions Without a Calculator
Five shortcuts that turn unit conversions into mental math you can do at the grocery store or on a trip.
Calculator7 Editorial Team
Unit conversions don't have to mean reaching for your phone. A few simple ratios cover 90% of everyday situations.
Five rules to memorize
1 mile ≈ 1.6 km. 1 kg ≈ 2.2 lb. 1 inch = 2.54 cm. 1 liter ≈ 0.26 gallons. °F = °C × 1.8 + 32.
For temperature, a quick shortcut: double the Celsius value and add 30. It's not exact, but it's close enough for weather forecasts.
Practice with real scenarios
Traveling to a metric country? Estimate distances using 'miles × 1.6'. Cooking with a foreign recipe? Remember 250 ml ≈ 1 cup. The more you practice, the more automatic it becomes.
