Unit Conversion Sheet
| Conversion | Formula | Example |
|---|---|---|
| inches → cm | ×2.54 | 12 in = 30.48 cm |
| feet → meters | ×0.3048 | 6 ft = 1.83 m |
| miles → km | ×1.60934 | 10 mi = 16.09 km |
| lbs → kg | ×0.45359 | 150 lbs = 68.04 kg |
| oz → grams | ×28.3495 | 8 oz = 226.80 g |
| °F → °C | (°F−32)×5/9 | 72°F = 22.2°C |
| gallons → liters | ×3.78541 | 5 gal = 18.93 L |
| ft² → m² | ×0.09290 | 1000 ft² = 92.9 m² |
How to Use a Unit Conversion Sheet for Exams
Dimensional Analysis Step-by-Step
Dimensional analysis is the most reliable method for unit conversion: (1) Write the starting value with units, (2) Multiply by conversion factors written as fractions that equal 1, (3) Cancel matching units, (4) Calculate the result. Example: 60 mph → km/h: 60 mi/h × 1.60934 km/mi = 96.56 km/h. For speed conversions, use our speed converter.
Metric Prefix Ladder Method
The metric prefix ladder helps students visualize conversions: kilo (10³) → base (10⁰) → milli (10⁻³) → micro (10⁻⁶) → nano (10⁻⁹). Moving down the ladder multiplies by 1000 each step. Example: 5 km = 5,000 m = 5,000,000 mm. Moving up divides by 1000: 5,000 mA = 5 A.
Avoiding Common Conversion Errors
The most frequent errors: (1) Inverting the conversion factor (multiplying when you should divide), (2) Forgetting squared/cubed units (1 m² ≠ 100 cm², it equals 10,000 cm²), (3) Mixing mass and weight, (4) Using the wrong temperature formula. Always check that your answer's magnitude makes physical sense.
Engineering Applications of Conversion Sheets
Laboratory Measurements
Laboratory work requires precise unit handling: molarity (mol/L), concentration (g/L or ppm), pressure (Pa, atm, mmHg), temperature (K, °C, °F). A unit conversion sheet ensures consistent calculations across experiments. For chemistry-specific conversions, see our chemical unit conversion guide.
Technical Drawing Conversions
Engineering drawings may use millimeters (ISO standard), inches (ANSI standard), or mixed units. Common scales: 1:1 (full size), 1:2 (half size), 1:10 (architectural). Converting between drawing units and real-world dimensions is a daily task in mechanical and civil engineering.