Unit Conversion Calculator & Chart
Complete Guide to Units of Measurement and Conversions
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What are Unit Conversions?
Unit conversion is the process of changing a measurement from one unit to another equivalent unit while maintaining the same quantity. This fundamental concept is essential in science, engineering, medicine, cooking, construction, and everyday life.
Units of measurement provide a standard way to express physical quantities such as length, mass, time, temperature, and volume. Different countries, industries, and scientific fields often use different unit systems, making conversions necessary for communication, calculation, and comparison.
The most common unit systems include the International System of Units (SI), the Imperial system (used primarily in the United States), and various specialized systems used in specific fields like astronomy, medicine, and engineering.
Major Unit Systems
🌍 Metric System (SI)
Used by: 95% of the world
- Length: Meter (m)
- Mass: Kilogram (kg)
- Time: Second (s)
- Temperature: Kelvin (K) / Celsius (°C)
- Volume: Liter (L)
- Advantage: Decimal-based, logical prefixes
🇺🇸 Imperial System
Used by: USA, UK (partially)
- Length: Inch, Foot, Yard, Mile
- Mass: Pound (lb), Ounce (oz)
- Temperature: Fahrenheit (°F)
- Volume: Gallon, Quart, Pint, Cup
- Challenge: Non-decimal relationships
🔬 Scientific Units
Used by: Scientists worldwide
- Energy: Joule (J), Calorie (cal)
- Pressure: Pascal (Pa), Atmosphere (atm)
- Power: Watt (W)
- Force: Newton (N)
- Advantage: Standardized for research
Comprehensive Unit Conversion Charts
📏 Length/Distance Conversions
| Unit | Symbol | Meters (m) | Feet (ft) | Inches (in) |
|---|---|---|---|---|
| Millimeter | mm | 0.001 | 0.00328 | 0.0394 |
| Centimeter | cm | 0.01 | 0.0328 | 0.394 |
| Meter | m | 1.0 | 3.28 | 39.4 |
| Kilometer | km | 1,000 | 3,280 | 39,370 |
| Inch | in | 0.0254 | 0.0833 | 1.0 |
| Foot | ft | 0.305 | 1.0 | 12.0 |
| Yard | yd | 0.914 | 3.0 | 36.0 |
| Mile | mi | 1,609 | 5,280 | 63,360 |
⚖️ Weight/Mass Conversions
| Unit | Symbol | Grams (g) | Kilograms (kg) | Pounds (lb) |
|---|---|---|---|---|
| Milligram | mg | 0.001 | 0.000001 | 0.0000022 |
| Gram | g | 1.0 | 0.001 | 0.0022 |
| Kilogram | kg | 1,000 | 1.0 | 2.20 |
| Ounce | oz | 28.35 | 0.0284 | 0.0625 |
| Pound | lb | 454 | 0.454 | 1.0 |
| Ton (Metric) | t | 1,000,000 | 1,000 | 2,204 |
🌡️ Temperature Conversion Formulas
Celsius to Fahrenheit
\[ °F = (°C × \frac{9}{5}) + 32 \]
Fahrenheit to Celsius
\[ °C = (°F - 32) × \frac{5}{9} \]
Celsius to Kelvin
\[ K = °C + 273.15 \]
Key Reference Points
- Water Freezes: 0°C = 32°F
- Water Boils: 100°C = 212°F
- Body Temp: 37°C = 98.6°F
Essential Conversion Factors
🥤 Volume Conversions
- 1 Liter = 1,000 ml = 1.06 qt = 0.264 gal
- 1 Gallon (US) = 3.785 L = 4 qt = 8 pt
- 1 Cup = 240 ml = 16 tbsp = 48 tsp
- 1 Fluid Ounce = 29.57 ml = 2 tbsp
- 1 Tablespoon = 15 ml = 3 tsp
📐 Area Conversions
- 1 m² = 10.76 ft² = 1,550 in²
- 1 km² = 100 hectares = 0.386 mi²
- 1 Acre = 4,047 m² = 43,560 ft²
- 1 ft² = 0.093 m² = 144 in²
- 1 Hectare = 10,000 m² = 2.47 acres
🏃 Speed Conversions
- 1 m/s = 3.6 km/h = 2.24 mph
- 1 km/h = 0.278 m/s = 0.621 mph
- 1 mph = 1.609 km/h = 0.447 m/s
- 1 Knot = 1.852 km/h = 1.151 mph
- Speed of Light = 299,792,458 m/s
⚡ Energy Conversions
- 1 Joule = 0.239 cal = 0.000278 Wh
- 1 Calorie = 4.184 J = 0.00116 Wh
- 1 kWh = 3.6 MJ = 860 kcal
- 1 BTU = 1,055 J = 252 cal
- 1 Food Calorie = 1 kcal = 4,184 J
🌊 Pressure Conversions
- 1 Pascal = 1 N/m² = 0.000145 psi
- 1 Atmosphere = 101.3 kPa = 14.7 psi
- 1 Bar = 100 kPa = 0.987 atm
- 1 PSI = 6.895 kPa = 0.068 atm
- 1 mmHg = 133.3 Pa = 0.019 psi
⏰ Time Conversions
- 1 Minute = 60 seconds
- 1 Hour = 60 minutes = 3,600 seconds
- 1 Day = 24 hours = 1,440 minutes
- 1 Week = 7 days = 168 hours
- 1 Year = 365.25 days = 8,766 hours
Practical Applications of Unit Conversions
👩🍳 Cooking & Baking
- Converting recipe measurements between metric and imperial
- Temperature conversions for oven settings
- Scaling recipes up or down
- Converting between volume and weight measurements
- International recipe adaptations
🏗️ Construction & Engineering
- Blueprint measurements and specifications
- Material quantity calculations
- Pressure and force calculations
- Area and volume calculations for projects
- International building code compliance
🔬 Science & Medicine
- Dosage calculations based on body weight
- Laboratory measurement conversions
- Temperature monitoring and recording
- Concentration and dilution calculations
- International research collaboration
✈️ Travel & Navigation
- Distance calculations for trip planning
- Speed limit understanding in different countries
- Fuel efficiency calculations (mpg vs L/100km)
- Weather temperature conversions
- International driving and navigation
💼 Business & Commerce
- International trade and shipping calculations
- Product specifications for global markets
- Manufacturing and quality control
- Energy consumption and efficiency
- Supply chain optimization
📚 Education & Academia
- Physics and chemistry problem solving
- Mathematics and engineering calculations
- International curriculum standards
- Research data analysis and comparison
- Student exchange program preparation
Unit Conversion Tips & Best Practices
🎯 Accuracy Tips
- Use precise conversion factors, not rounded approximations
- Maintain significant figures throughout calculations
- Double-check critical conversions with multiple sources
- Consider measurement uncertainty and tolerances
- Use dimensional analysis to verify calculations
❌ Common Mistakes
- Confusing US and Imperial gallon (US = 3.785L, UK = 4.546L)
- Mixing up mass and weight in different gravity
- Using incorrect temperature formulas
- Forgetting to square or cube units for area/volume
- Misunderstanding compound units (like km/h to m/s)
🧠 Mental Math Tricks
- Celsius to Fahrenheit: Double and add 30 (approximate)
- Miles to Kilometers: Multiply by 1.6 or use Fibonacci sequence
- Pounds to Kilograms: Divide by 2.2
- Inches to Centimeters: Multiply by 2.5
- Feet to Meters: Divide by 3.28
About the Author
Adam
Co-Founder @ RevisionTown
Math Expert specializing in various curricula including IB, AP, GCSE, IGCSE, and more