Unit Converter Guide: Over 6,000 Conversions in 37 Categories

Calc Pro's Unit Converter handles virtually any measurement conversion you'll ever need. With 37 categories and over 6,000 conversions, it's the most comprehensive conversion tool at your fingertips.

Overview

The Unit Converter features:

• 37 conversion categories: 19 everyday categories, plus 18 specialist categories with Pro Premium in the iPhone & iPad app
• Over 6,000 conversions
• Instant real-time conversion
• Easy-to-use interface

The 19 Everyday Categories

These 19 categories are included free.

1. Distance

Convert between units of length and distance.

Unit	Abbreviation	Description
Meter	m	SI base unit
Kilometer	km	1000 meters
Centimeter	cm	0.01 meters
Millimeter	mm	0.001 meters
Mile	mi	1.609 km
Yard	yd	0.9144 m
Foot	ft	0.3048 m
Inch	in	2.54 cm
Nautical Mile	nmi	1852 m
Light Year	ly	9.461×10¹⁵ m
Parsec	pc	3.086×10¹⁶ m

Common conversions:

• 1 mile = 1.609 kilometers
• 1 inch = 2.54 centimeters
• 1 foot = 12 inches = 30.48 cm

2. Temperature

Convert between temperature scales.

Unit	Symbol	Zero Point
Celsius	°C	Water freezes at 0°
Fahrenheit	°F	Water freezes at 32°
Kelvin	K	Absolute zero at 0
Rankine	°R	Absolute zero at 0

Formulas:

• °F = (°C × 9/5) + 32
• K = °C + 273.15
• °R = (°C + 273.15) × 9/5

Common reference points:

• Water freezes: 0°C = 32°F = 273.15K
• Water boils: 100°C = 212°F = 373.15K
• Body temperature: 37°C = 98.6°F

3. Speed

Convert velocity measurements.

Unit	Abbreviation
Meters per second	m/s
Kilometers per hour	km/h
Miles per hour	mph
Feet per second	ft/s
Knots	kn
Mach	Ma

Useful conversions:

• 1 m/s ≈ 3.6 km/h ≈ 2.237 mph
• 1 knot = 1.852 km/h (nautical)
• Mach 1 ≈ 343 m/s (at sea level, 20°C)

4. Weight / Mass

Convert between mass and weight units.

Unit	Abbreviation	Value in kg
Kilogram	kg	1
Gram	g	0.001
Milligram	mg	0.000001
Metric Ton	t	1000
Pound	lb	0.4536
Ounce	oz	0.02835
Stone	st	6.35
Short Ton	US ton	907.2
Long Ton	UK ton	1016
Carat	ct	0.0002

Common conversions:

• 1 kg ≈ 2.205 pounds
• 1 pound = 16 ounces
• 1 stone = 14 pounds

5. Area

Convert surface area measurements.

Unit	Description
Square meter (m²)	SI unit
Square kilometer (km²)	1,000,000 m²
Hectare (ha)	10,000 m²
Acre	4,047 m²
Square mile (mi²)	2.59 km²
Square yard (yd²)	0.836 m²
Square foot (ft²)	0.0929 m²
Square inch (in²)	6.452 cm²

Useful conversions:

• 1 acre = 43,560 sq ft
• 1 hectare ≈ 2.47 acres
• 1 sq mile = 640 acres

6. Volume

Convert capacity and volume measurements.

Unit	Volume
Liter (L)	1000 cm³
Milliliter (mL)	1 cm³
Cubic meter (m³)	1000 L
Gallon (US)	3.785 L
Gallon (UK)	4.546 L
Quart	0.946 L
Pint	0.473 L
Cup	0.237 L
Fluid ounce	29.57 mL
Tablespoon	14.79 mL
Teaspoon	4.93 mL

Note: US and Imperial gallons differ!

• US gallon = 3.785 liters
• UK gallon = 4.546 liters

7. Time

Convert time intervals.

Unit	Value
Second	Base unit
Millisecond	0.001 seconds
Minute	60 seconds
Hour	3600 seconds
Day	86400 seconds
Week	604800 seconds
Month (avg)	~2.628×10⁶ seconds
Year	~3.154×10⁷ seconds

8. Pressure

Convert pressure and stress measurements.

Unit	Description
Pascal (Pa)	SI unit
Kilopascal (kPa)	1000 Pa
Bar	100,000 Pa
Atmosphere (atm)	101,325 Pa
PSI	Pounds per sq inch
Torr/mmHg	133.3 Pa

Common conversions:

• 1 atm = 101.325 kPa = 14.7 PSI
• 1 bar ≈ 0.987 atm

9. Energy

Convert energy and work measurements.

Unit	Description
Joule (J)	SI unit
Kilojoule (kJ)	1000 J
Calorie	4.184 J
Kilocalorie (food Cal)	4184 J
Watt-hour (Wh)	3600 J
Kilowatt-hour (kWh)	3.6 MJ
BTU	1055 J
Electron volt (eV)	1.602×10⁻¹⁹ J

Note: Food "Calories" are kilocalories (kcal).

10. Power

Convert power and rate of energy transfer.

Unit	Description
Watt (W)	SI unit
Kilowatt (kW)	1000 W
Megawatt (MW)	10⁶ W
Horsepower (hp)	745.7 W
BTU/hour	0.293 W

Useful conversion:

• 1 horsepower ≈ 0.746 kilowatts

11. Data Storage

Convert digital storage units.

Unit	Value
Bit (b)	Base unit
Byte (B)	8 bits
Kilobyte (KB)	1000 B
Kibibyte (KiB)	1024 B
Megabyte (MB)	10⁶ B
Mebibyte (MiB)	2²⁰ B
Gigabyte (GB)	10⁹ B
Gibibyte (GiB)	2³⁰ B
Terabyte (TB)	10¹² B
Tebibyte (TiB)	2⁴⁰ B

Note the difference:

• Decimal: KB, MB, GB (×1000)
• Binary: KiB, MiB, GiB (×1024)

12. Flow Rate

Convert how much liquid or gas moves in a given time.

Unit	Common use
Liters per second/minute/hour	Pumps, taps and hoses
Milliliters per minute	IV drips and lab work
Cubic meters per second/minute/hour/day	Rivers, HVAC and water supply
Cubic feet per second/minute/hour/day	Streams, ventilation (CFM)
US and UK gallons per second/minute/hour/day	Plumbing and irrigation
Million US gallons per day	Water treatment plants
Oil barrels per day	Oil production

Practical example:

• 1 US gallon per minute ≈ 3.785 liters per minute

13. Acceleration

Convert acceleration measurements.

Unit	Description
m/s²	SI unit
ft/s²	Imperial
g (gravity)	9.807 m/s²
Gal	0.01 m/s²

14. Density

Convert density measurements.

Unit	Description
kg/m³	SI unit
g/cm³	Common for liquids
lb/ft³	Imperial
lb/gal	Liquids (US)

Common densities:

• Water: 1 g/cm³ = 1000 kg/m³
• Air: ~1.225 kg/m³ at sea level

15. Force

Convert force measurements.

Unit	Description
Newton (N)	SI unit
Kilonewton (kN)	1000 N
Dyne	10⁻⁵ N
Pound-force (lbf)	4.448 N
Kilogram-force (kgf)	9.807 N

16. Torque

Convert rotational force measurements.

Unit	Description
Newton-meter (N·m)	SI unit
Foot-pound (ft·lb)	1.356 N·m
Inch-pound	0.113 N·m

Useful for:

• Automotive torque specs
• Engineering applications

17. Fuel Economy

Convert fuel efficiency measurements.

Unit	Description
km/L	Kilometers per liter
mi/gal (US)	Miles per gallon
mi/gal (UK)	Imperial MPG
L/100km	Liters per 100 km

Note: L/100km is inverse (lower = more efficient)

• 50 MPG ≈ 4.7 L/100km

18. Angle

Convert angular measurements.

Unit	Description
Degree (°)	360 per circle
Radian (rad)	2π per circle
Gradian (grad)	400 per circle
Arc minute (')	1/60 degree
Arc second (")	1/60 arc minute

Key conversion:

• π radians = 180°
• 1 radian ≈ 57.296°

19. Cooking Measurements

Convert kitchen measurements.

Unit	Description
Cup	Standard cooking cup
Tablespoon	3 teaspoons
Teaspoon	Standard tsp
Fluid ounce	Volume measure
Milliliter	Metric

18 Specialist Categories — Pro Premium

In the iPhone & iPad app, these categories unlock with the Pro Premium in-app purchase.

Category	Used for
Concentration	Chemistry and lab solutions
Data Transfer	Internet and network speeds (bps, Mbps, MB/s)
Electric Charge	Electronics and physics
Electric Current	Electronics and electrical work
Frequency	Radio, audio and rotating machinery (Hz, rpm)
Illuminance	Lighting design and photography
Magnetism	Physics and engineering
Metric Prefixes	Moving between nano, micro, milli, kilo, mega and more
Radiation Dose	Medical and radiation safety
Radioactivity	Nuclear physics and safety
Resistance	Electronics
Specific Heat	Thermodynamics and heat transfer
Surface Tension	Fluid science
Thermal Conductivity	Insulation and heat transfer
Typography	Print and web design
Viscosity (Dynamic)	Fluids and lubricants
Viscosity (Kinematic)	Fluids and lubricants
Voltage	Electronics and electrical work

Practical example (Data Transfer):

• 100 Mbps connection = 12.5 MB/s theoretical max

How to Use the Unit Converter

Step 1: Select Category

1. Open the Unit Converter
2. Browse the category list
3. Tap your desired category (e.g., "Distance")

Step 2: Choose Units

1. Select the "From" unit (source)
2. Select the "To" unit (target)

Step 3: Enter Value

1. Type your value using the number pad
2. The conversion displays instantly

Example: Convert 5 Miles to Kilometers

1. Open Unit Converter
2. Select "Distance" category
3. Set "From": Miles
4. Set "To": Kilometers
5. Enter: 5
6. Result: 8.047 km

Advanced Tips

Chaining Conversions

Convert through an intermediate unit:

• Miles → Meters → Centimeters

Understanding Precision

Calc Pro maintains high precision internally but displays rounded values. The full precision is used in calculations.

Favorite Conversions

Frequently used conversions are easy to access—the most common units appear first in each category.

Real-World Applications

Cooking

Converting recipes between metric and imperial:

• "250g flour" → "2.08 cups" (approximately)
• "350°F" → "177°C" oven temperature

Travel

Understanding foreign measurements:

• Speed limits in km/h vs mph
• Fuel economy comparisons
• Temperature for weather forecasts

Shopping

Comparing prices across different units:

• Price per ounce vs price per gram
• Square footage vs square meters for real estate

Health & Fitness

• Weight tracking (lbs ↔ kg)
• Running distances (miles ↔ km)
• Calorie counting (calories ↔ kilojoules)

Science & Engineering

• Unit analysis in physics problems
• Converting between measurement systems
• Checking calculation results

Quick Reference Cards

Length Quick Reference

From	To	Multiply by
inches	cm	2.54
feet	m	0.3048
miles	km	1.609
yards	m	0.9144

Weight Quick Reference

From	To	Multiply by
pounds	kg	0.4536
ounces	g	28.35
stones	kg	6.35

Volume Quick Reference

From	To	Multiply by
gallons (US)	liters	3.785
quarts	liters	0.946
cups	mL	237

Conclusion

Calc Pro's Unit Converter eliminates the guesswork from measurement conversions. With 37 categories covering virtually every type of unit you'll encounter, it's your go-to tool for cooking, traveling, studying, or working in any field that involves measurements.

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