Ultimate Guide to Unit Conversion
Unit conversion is essential in daily life - from cooking to construction, travel to science. Master all common conversions with formulas and our free calculators.
Types of Unit Conversions
1. Length Conversion
Convert between:
- Metric: mm, cm, m, km
- Imperial: inch, foot, yard, mile
- Length Converter
2. Weight Conversion
Convert between:
- Metric: mg, g, kg, tonne
- Imperial: ounce, pound, stone, ton
- Weight Converter
3. Temperature Conversion
Convert between:
- Celsius (°C)
- Fahrenheit (°F)
- Kelvin (K)
- Temperature Converter
4. Volume Conversion
Convert between:
- Metric: ml, l, cubic meter
- Imperial: fluid ounce, cup, pint, gallon
- Volume Converter
5. Area Conversion
Convert between:
- Metric: sq cm, sq m, hectare, sq km
- Imperial: sq inch, sq foot, acre, sq mile
- Indian: Bigha, Gaj, Kanal
- Area Converter
6. Speed Conversion
Convert between:
- km/h, m/s, mph, knots
- Speed Converter
7. Time Conversion
Convert between:
- Seconds, minutes, hours, days, weeks, months, years
- Time Converter
8. Currency Conversion
Convert between currencies with live rates
Length Conversion
Metric System
| Unit | Conversion | |------|-----------| | 1 km | 1,000 meters | | 1 m | 100 centimeters | | 1 cm | 10 millimeters |
Imperial System
| Unit | Conversion | |------|-----------| | 1 mile | 1,760 yards | | 1 yard | 3 feet | | 1 foot | 12 inches |
Metric ↔ Imperial
| Conversion | Formula | |-----------|---------| | Inch to cm | inch × 2.54 | | Foot to meter | foot × 0.3048 | | Yard to meter | yard × 0.9144 | | Mile to km | mile × 1.609 | | Meter to foot | meter × 3.281 | | Km to mile | km × 0.621 |
Examples
Example 1: Convert 5 feet 6 inches to cm
- 5 feet = 5 × 30.48 = 152.4 cm
- 6 inches = 6 × 2.54 = 15.24 cm
- Total = 167.64 cm
Example 2: Convert 180 cm to feet-inches
- 180 ÷ 30.48 = 5.905 feet
- 5 feet + (0.905 × 12) inches
- 5 feet 10.86 inches ≈ 5'11"
Quick convert: Length Converter
Weight Conversion
Metric System
| Unit | Conversion | |------|-----------| | 1 tonne | 1,000 kg | | 1 kg | 1,000 grams | | 1 g | 1,000 milligrams |
Imperial System
| Unit | Conversion | |------|-----------| | 1 ton | 2,000 pounds | | 1 stone | 14 pounds | | 1 pound | 16 ounces |
Metric ↔ Imperial
| Conversion | Formula | |-----------|---------| | Kg to pound | kg × 2.205 | | Pound to kg | pound × 0.454 | | Gram to ounce | gram × 0.035 | | Ounce to gram | ounce × 28.35 |
Examples
Example 1: Convert 70 kg to pounds
- 70 × 2.205 = 154.35 lbs
Example 2: Convert 150 pounds to kg
- 150 × 0.454 = 68.1 kg
Try: Weight Converter
Temperature Conversion
Formulas
Celsius to Fahrenheit: °F = (°C × 9/5) + 32
Fahrenheit to Celsius: °C = (°F - 32) × 5/9
Celsius to Kelvin: K = °C + 273.15
Fahrenheit to Kelvin: K = (°F - 32) × 5/9 + 273.15
Common Temperatures
| Celsius | Fahrenheit | Description | |---------|-----------|-------------| | -40°C | -40°F | Same value! | | 0°C | 32°F | Water freezes | | 10°C | 50°F | Cool | | 20°C | 68°F | Room temp | | 37°C | 98.6°F | Body temp | | 100°C | 212°F | Water boils |
Examples
Example 1: Convert 25°C to Fahrenheit
- °F = (25 × 9/5) + 32
- °F = 45 + 32 = 77°F
Example 2: Convert 70°F to Celsius
- °C = (70 - 32) × 5/9
- °C = 38 × 5/9 = 21.1°C
Instant conversion: Temperature Converter
Volume Conversion
Metric System
| Unit | Conversion | |------|-----------| | 1 liter | 1,000 milliliters | | 1 cubic meter | 1,000 liters |
Imperial System
| Unit | Conversion | |------|-----------| | 1 gallon | 4 quarts | | 1 quart | 2 pints | | 1 pint | 2 cups | | 1 cup | 8 fluid ounces |
Metric ↔ Imperial
| Conversion | Formula | |-----------|---------| | Liter to gallon | liter × 0.264 | | Gallon to liter | gallon × 3.785 | | Ml to fl oz | ml × 0.034 | | Cup to ml | cup × 236.588 |
Cooking Conversions
Indian Measurements:
- 1 cup = 240 ml
- 1 tbsp = 15 ml
- 1 tsp = 5 ml
Common Ingredients:
- 1 cup flour = 120 g
- 1 cup sugar = 200 g
- 1 cup rice = 180 g
- 1 cup water = 240 ml
More: Cooking Unit Converter | Cups to Grams
Area Conversion
Metric System
| Unit | Conversion | |------|-----------| | 1 sq km | 100 hectares | | 1 hectare | 10,000 sq meters | | 1 sq meter | 10,000 sq cm |
Imperial System
| Unit | Conversion | |------|-----------| | 1 sq mile | 640 acres | | 1 acre | 4,840 sq yards | | 1 sq yard | 9 sq feet | | 1 sq foot | 144 sq inches |
Indian Land Measurements
| Unit | Conversion | |------|-----------| | 1 Acre | 43,560 sq feet | | 1 Bigha | ~27,225 sq feet (varies by state) | | 1 Gaj | 1 sq yard = 9 sq feet | | 1 Guntha | 1,089 sq feet | | 1 Cent | 435.6 sq feet |
Metric ↔ Imperial
| Conversion | Formula | |-----------|---------| | Sq meter to sq foot | sq m × 10.764 | | Sq foot to sq meter | sq ft × 0.093 | | Acre to hectare | acre × 0.405 | | Hectare to acre | hectare × 2.471 |
Examples
Example 1: 1,000 sq ft apartment in sq meters
- 1000 × 0.093 = 93 sq meters
Example 2: 1 acre plot in sq meters
- 1 × 4,047 = 4,047 sq meters
Calculate: Area Converter
Speed Conversion
Common Conversions
| From → To | Formula | |----------|---------| | km/h → mph | km/h × 0.621 | | mph → km/h | mph × 1.609 | | m/s → km/h | m/s × 3.6 | | km/h → m/s | km/h × 0.278 | | knots → km/h | knots × 1.852 |
Examples
Example 1: Speed limit 100 km/h in mph
- 100 × 0.621 = 62.1 mph
Example 2: Running speed 5 m/s in km/h
- 5 × 3.6 = 18 km/h
Convert: Speed Converter
Time Conversion
Basic Time Units
| Unit | Conversion | |------|-----------| | 1 year | 365 days (366 in leap year) | | 1 month | 30-31 days (28-29 for Feb) | | 1 week | 7 days | | 1 day | 24 hours | | 1 hour | 60 minutes | | 1 minute | 60 seconds |
Quick Calculations
| Conversion | Formula | |-----------|---------| | Days to hours | days × 24 | | Hours to minutes | hours × 60 | | Minutes to seconds | minutes × 60 | | Weeks to days | weeks × 7 | | Years to days | years × 365.25 |
Examples
Example 1: 2 weeks in hours
- 2 × 7 × 24 = 336 hours
Example 2: 10,000 seconds in hours
- 10000 ÷ 60 ÷ 60 = 2.78 hours ≈ 2 hours 47 minutes
Calculate: Time Converter
Currency Conversion
Popular Conversions
- INR to USD (Rupee to Dollar)
- USD to INR (Dollar to Rupee)
- EUR to INR (Euro to Rupee)
- GBP to INR (Pound to Rupee)
- AED to INR (Dirham to Rupee)
Live Rates
Currency rates change daily. Use our converter for real-time rates: Currency Converter
Travel Calculations
Example: You have $1,000 USD, exchange rate is ₹83/USD
- Amount in INR = 1000 × 83 = ₹83,000
Conversion Shortcuts & Tricks
Length Shortcuts
- Quick feet to cm: Multiply by 30
- Quick inch to cm: Multiply by 2.5
- Quick mile to km: Multiply by 1.6 (or 8/5)
- Quick km to mile: Multiply by 0.6 (or 3/5)
Weight Shortcuts
- Quick kg to pound: Double it, add 10%
- 50 kg: 50×2 = 100, +5 = 105 lbs (actual: 110 lbs)
- Quick pound to kg: Halve it, subtract 10%
- 100 lbs: 100÷2 = 50, -5 = 45 kg (actual: 45.4 kg)
Temperature Shortcuts
- Quick °C to °F: Double it, add 30
- 20°C: 20×2 + 30 = 70°F (actual: 68°F)
- Quick °F to °C: Subtract 30, halve it
- 80°F: (80-30)÷2 = 25°C (actual: 26.7°C)
Note: These are approximations for mental math!
Common Conversion Mistakes
❌ Mistake 1: Mixing Systems
Don't mix metric and imperial in same calculation.
✅ Solution: Convert everything to one system first.
❌ Mistake 2: Wrong Formula Direction
Using multiplication instead of division (or vice versa).
✅ Solution: Remember: larger unit has smaller number.
❌ Mistake 3: Rounding Too Early
Rounding intermediate results causes errors.
✅ Solution: Round only the final answer.
❌ Mistake 4: Forgetting Square/Cubic
Area/Volume conversions require squaring/cubing factors.
✅ Solution:
- 1 sq foot = (0.3048)² sq meters
- 1 cu foot = (0.3048)³ cu meters
Real-World Conversion Examples
Example 1: Cooking Recipe
Problem: American recipe calls for 2 cups flour. Convert to grams.
- 2 cups × 120 g/cup = 240 grams
Example 2: Travel Distance
Problem: Road trip is 500 miles. Convert to km.
- 500 × 1.609 = 804.5 km
Use: Distance Calculator
Example 3: Property Size
Problem: Apartment is 1,200 sq feet. Convert to sq meters.
- 1200 × 0.093 = 111.6 sq meters
Use: Area Converter
Example 4: Body Weight
Problem: You weigh 165 pounds. Convert to kg.
- 165 × 0.454 = 74.9 kg
Use: Weight Converter | BMI Calculator
Example 5: Weather Report
Problem: Weather forecast is 86°F. Convert to Celsius.
- (86 - 32) × 5/9 = 30°C
Example 6: Fuel Efficiency
Problem: Car gives 15 km/l. Convert to mpg (miles per gallon).
- 15 × 2.352 = 35.3 mpg
Example 7: Running Pace
Problem: Running at 10 km/h. Convert to minutes per km.
- 60 ÷ 10 = 6 minutes/km
Industry-Specific Conversions
Construction & Real Estate
- Area Converter - Plot sizes
- Concrete Calculator - Volume
- Paint Calculator - Area coverage
- Tile Calculator - Floor area
Health & Fitness
- BMI Calculator - Weight/Height
- Calorie Calculator - Energy
- Body Fat Calculator - Percentage
Cooking & Baking
- Cooking Unit Converter - All units
- Cups to Grams - Weight
- Recipe Converter - Servings
- Oven Temperature - Heat
Travel & Navigation
- Currency Converter - Money
- Time Zone Converter - Time
- Distance Calculator - Routes
All Conversion Calculators
Basic Converters
Unit Converter | Length Converter | Weight Converter | Temperature Converter | Volume Converter | Area Converter | Speed Converter | Time Converter
Specialized Converters
Currency Converter | Fraction to Decimal | Percentage Calculator | Time Zone Converter | Number Base Converter | ASCII Converter | Color Converter
Cooking Converters
Cooking Unit Converter | Cups to Grams | Recipe Converter | Oven Temperature
Conclusion
Unit conversion is a fundamental skill used daily across all professions and activities. Whether you're cooking, traveling, shopping, or working, knowing how to convert units accurately saves time and prevents errors.
Key Takeaways:
- Learn common conversion factors
- Use mental math shortcuts for quick estimates
- Always double-check critical conversions
- Use online calculators for precise results
- Remember: larger unit = smaller number
👉 Convert any unit instantly: Free Unit Converter
Related Guides:
Quick Access Converters: Length | Weight | Temperature | Volume | Area | Speed | Currency | Time Zone
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