Temperature Conversion
Temperature is more than just a number on a weather app — it’s a critical measurement in cooking, science, health, and everyday comfort. Around the world, different scales are used, including Celsius (°C), Fahrenheit (°F), and Kelvin (K). Understanding how to convert between them helps avoid confusion whether you’re setting your oven, checking body temperature, or interpreting lab data.
Celsius to Fahrenheit
To convert Celsius to Fahrenheit, use the formula:
°F = (°C × 9/5) + 32
Examples:
Celsius (°C) | Formula | Fahrenheit (°F) |
---|---|---|
0 | (0 × 9/5) + 32 | 32 |
10 | (10 × 9/5) + 32 | 50 |
20 | (20 × 9/5) + 32 | 68 |
30 | (30 × 9/5) + 32 | 86 |
100 | (100 × 9/5) + 32 | 212 |
Fahrenheit to Celsius
To convert Fahrenheit to Celsius, use this formula:
°C = (°F − 32) × 5/9
Examples:
Fahrenheit (°F) | Formula | Celsius (°C) |
---|---|---|
32 | (32 − 32) × 5/9 = 0 × 5/9 | 0 |
68 | (68 − 32) × 5/9 = 36 × 5/9 | 20 |
98.6 | (98.6 − 32) × 5/9 = 66.6 × 5/9 | 37 |
212 | (212 − 32) × 5/9 = 180 × 5/9 | 100 |
Celsius to Kelvin
Kelvin is used in scientific contexts and starts at absolute zero.
K = °C + 273.15
Examples:
Celsius (°C) | Kelvin (K) |
---|---|
-273.15 | 0 |
0 | 273.15 |
25 | 298.15 |
100 | 373.15 |
Quick Reference Summary
°C | °F | K |
---|---|---|
-40 | -40 | 233.15 |
0 | 32 | 273.15 |
20 | 68 | 293.15 |
37 | 98.6 | 310.15 |
100 | 212 | 373.15 |
Length Conversion
Length is one of the most commonly used measurements in daily life — from checking your height, measuring a piece of wood, calculating walking distance, or understanding product dimensions. Different regions use either the metric system (millimeters, centimeters, meters, kilometers) or the imperial system (inches, feet, yards, miles), and switching between them is often necessary.
Metric System Basics
These conversions are based on powers of ten, making the metric system highly logical and easy to use:
- 1 centimeter = 10 millimeters
- 1 meter = 100 centimeters = 1,000 millimeters
- 1 kilometer = 1,000 meters
Metric Examples
Unit | Conversion |
---|---|
1 cm | 10 mm |
1 m | 100 cm = 1,000 mm |
1.5 m | 150 cm = 1,500 mm |
2.3 km | 2,300 m = 230,000 cm |
Imperial System Basics
The imperial system is used in the United States and parts of the UK. The most common units are:
- 1 foot = 12 inches
- 1 yard = 3 feet = 36 inches
- 1 mile = 5,280 feet = 1,760 yards
Imperial Examples
Unit | Equivalent |
---|---|
1 ft | 12 in |
3 ft | 36 in = 1 yd |
2 miles | 10,560 ft = 3,520 yds |
Metric to Imperial Conversion
These conversions are approximate but commonly used:
- 1 inch = 2.54 centimeters
- 1 foot = 30.48 centimeters = 0.3048 meters
- 1 yard = 0.9144 meters
- 1 mile = 1.609 kilometers
Examples: Metric to Imperial
Metric Value | Imperial Equivalent |
---|---|
10 cm | 3.94 inches |
1 m | 3.28 feet (39.37 inches) |
100 m | 109.36 yards |
5 km | 3.11 miles |
Imperial to Metric Conversion
Reverse conversions:
- 1 inch ≈ 0.3937 cm
- 1 foot ≈ 0.3048 m
- 1 yard ≈ 0.9144 m
- 1 mile ≈ 1.609 km
Examples: Imperial to Metric
Imperial Value | Metric Equivalent |
---|---|
5 in | 12.7 cm |
6 ft | 1.83 m |
100 yd | 91.44 m |
2 miles | 3.218 km |
Quick Reference Table
Unit | Converts To |
---|---|
1 inch | 2.54 cm |
1 cm | 0.3937 inches |
1 foot | 0.3048 m |
1 meter | 3.2808 ft |
1 mile | 1.609 km |
1 km | 0.6214 miles |
Area Conversion
Area is used to describe the amount of surface a shape covers — whether it’s a room floor, a field, a wall, or even an entire plot of land. It’s crucial in real estate, agriculture, construction, architecture, and everyday measurements like square footage in homes or land size in hectares.
Metric Units of Area
The metric system handles area using squared versions of its length units:
- 1 square centimeter (cm²) = 100 mm²
- 1 square meter (m²) = 10,000 cm² = 1,000,000 mm²
- 1 hectare (ha) = 10,000 m²
- 1 square kilometer (km²) = 1,000,000 m² = 100 hectares
Metric Area Examples
Unit | Equivalent |
---|---|
1 m² | 10,000 cm² |
1 ha | 10,000 m² = 100 ares = 0.01 km² |
0.5 km² | 500,000 m² = 50 hectares |
25 cm × 25 cm | 625 cm² (area of a square) |
Imperial Units of Area
In countries using the imperial system, area is often measured in:
- square inches (in²)
- square feet (ft²)
- square yards (yd²)
- acres
- square miles (mi²)
Key relationships:
- 1 ft² = 144 in²
- 1 yd² = 9 ft²
- 1 acre = 43,560 ft² = 4,840 yd²
- 1 mi² = 640 acres
Imperial Area Examples
Unit | Equivalent |
---|---|
1 yd² | 9 ft² |
1 acre | 43,560 ft² |
1 mi² | 640 acres = 27,878,400 ft² |
Room: 12 ft × 15 ft | 180 ft² |
Metric ↔ Imperial Conversion
These are the most commonly needed cross-system conversions:
- 1 m² ≈ 10.764 ft²
- 1 ft² ≈ 0.092903 m²
- 1 acre ≈ 4,046.86 m² ≈ 0.4047 ha
- 1 ha = 10,000 m² ≈ 2.471 acres
Examples: Area Conversions
Value | Converted Value |
---|---|
100 m² | 1,076.4 ft² |
500 ft² | 46.45 m² |
1 hectare | 2.471 acres |
2 acres | 8,094 m² = 0.809 ha |
1 km² | 1,000,000 m² = 247.1 acres |
Quick Area Conversion Table
Unit | Equivalent |
---|---|
1 m² | 10.764 ft² |
1 ft² | 0.092903 m² |
1 ha | 10,000 m² = 2.471 acres |
1 acre | 4,046.86 m² = 0.4047 ha |
1 km² | 1,000,000 m² = 100 ha = 247.1 acres |
Volume Conversion
Volume tells us how much space something occupies — whether it’s water in a bottle, fuel in a tank, or ingredients in a recipe. Units of volume vary depending on the context: liters and milliliters in the metric world, gallons, quarts, and cups in the imperial system. Knowing how to convert between them is especially useful in cooking, science, and logistics.
Metric Units of Volume
The metric system makes volume conversions easy since it follows a decimal structure.
- 1 milliliter (mL) = 1 cubic centimeter (cm³)
- 1 liter (L) = 1,000 milliliters (mL)
- 1 cubic meter (m³) = 1,000 liters
Examples:
Unit | Equivalent |
---|---|
500 mL | 0.5 liters |
1 liter | 1,000 mL = 1,000 cm³ |
2.5 L | 2,500 mL |
1 m³ | 1,000 L = 1,000,000 mL |
Imperial Units of Volume
In the imperial system (primarily used in the U.S.), common volume units include:
- Fluid ounce (fl oz)
- Cup
- Pint (pt)
- Quart (qt)
- Gallon (gal)
Key relationships:
- 1 cup = 8 fl oz
- 1 pint = 2 cups = 16 fl oz
- 1 quart = 2 pints = 32 fl oz
- 1 gallon = 4 quarts = 128 fl oz
Metric to Imperial Conversions
These are approximate values commonly used:
- 1 liter ≈ 33.814 fl oz (US)
- 1 liter ≈ 1.057 quarts (US)
- 1 liter ≈ 0.2642 gallons (US)
- 1 mL ≈ 0.0338 fl oz
Examples:
Metric Value | Imperial Equivalent |
---|---|
250 mL | ≈ 8.45 fl oz |
500 mL | ≈ 16.91 fl oz = ~1 US pint |
1 liter | ≈ 33.81 fl oz = ~1.057 qt = 0.2642 gal |
2 liters | ≈ 67.63 fl oz = ~0.528 gal |
Imperial to Metric Conversions
These are also useful for interpreting American packaging or recipes:
- 1 US fluid ounce = 29.5735 mL
- 1 cup = 236.59 mL
- 1 pint = 473.18 mL
- 1 quart = 946.35 mL
- 1 gallon = 3.785 liters
Examples:
Imperial Value | Metric Equivalent |
---|---|
1 cup | ≈ 236.6 mL |
1 pint | ≈ 473.2 mL |
1 gallon | ≈ 3.785 liters |
12 fl oz | ≈ 355 mL (a standard soda can) |
Quick Volume Conversion Table
Unit | Equivalent |
---|---|
1 mL | 0.0338 fl oz |
1 liter | 1,000 mL ≈ 33.81 fl oz = 1.057 qt = 0.264 gal |
1 gallon (US) | 128 fl oz ≈ 3.785 L |
1 cup (US) | 8 fl oz ≈ 236.6 mL |
Weight Conversion
Weight (or more precisely, mass) is a measurement we constantly encounter — in cooking, travel, shipping, fitness, and science. Depending on where you live, you might use grams and kilograms, or ounces and pounds. Let’s walk through how to convert between the different units with ease.
Metric Units of Weight
The metric system is based on powers of ten and is straightforward to work with:
- 1 kilogram (kg) = 1,000 grams (g)
- 1 gram = 1,000 milligrams (mg)
- 1 tonne (metric ton) = 1,000 kilograms = 1,000,000 grams
Metric Examples
Unit | Equivalent |
---|---|
1 g | 1,000 mg |
1 kg | 1,000 g = 1,000,000 mg |
0.5 kg | 500 g |
2 tonnes | 2,000 kg = 2,000,000 g |
Imperial Units of Weight
Used primarily in the United States and a few other countries:
- 1 pound (lb) = 16 ounces (oz)
- 1 stone (UK, rarely used elsewhere) = 14 pounds
- 1 US ton = 2,000 pounds
- 1 UK (long) ton = 2,240 pounds
Imperial Examples
Unit | Equivalent |
---|---|
1 lb | 16 oz |
2 lbs | 32 oz |
1 stone | 14 lbs |
1 ton (US) | 2,000 lbs |
Metric to Imperial Conversion
These are widely used approximations:
- 1 kilogram = 2.2046 pounds
- 1 gram = 0.0353 ounces
- 1 tonne = 2,204.62 pounds
- 1 mg = 0.000035 oz
Examples: Metric to Imperial
Metric Value | Approximate Imperial Equivalent |
---|---|
100 g | 3.53 oz |
1 kg | 2.20 lbs |
2.5 kg | 5.51 lbs |
50 kg | 110.23 lbs |
1 tonne | 2,204.6 lbs |
Imperial to Metric Conversion
Use these key ratios:
- 1 pound = 0.4536 kilograms
- 1 ounce = 28.35 grams
- 1 ton (US) = 907.18 kilograms
- 1 stone = 6.35 kilograms
Examples: Imperial to Metric
Imperial Value | Approximate Metric Equivalent |
---|---|
1 lb | 453.6 g = 0.4536 kg |
10 oz | 283.5 g |
150 lbs | 68.04 kg |
1 stone | 6.35 kg |
1 US ton | 907.18 kg |
Quick Weight Conversion Table
Unit | Equivalent |
---|---|
1 g | 0.0353 oz |
1 kg | 2.2046 lbs |
1 lb | 16 oz = 0.4536 kg |
1 oz | 28.35 g |
1 stone | 14 lbs = 6.35 kg |
1 tonne | 1,000 kg ≈ 2,204.62 lbs |
1 US ton | 2,000 lbs ≈ 907.18 kg |
Speed Conversion
Speed measures how fast something moves — whether it’s a car on a highway, a runner on a track, or a plane in the sky. You’ll most commonly see speed expressed in kilometers per hour (km/h), miles per hour (mph), or meters per second (m/s). For nautical and aviation purposes, the unit knot is also used. Let’s see how these units compare and convert.
Common Speed Units
- Kilometers per hour (km/h) — used globally in road traffic
- Miles per hour (mph) — used in the US and UK for driving
- Meters per second (m/s) — used in physics and sports
- Knots (nautical miles per hour) — used in aviation and maritime
Kilometers per Hour to Meters per Second
Conversion:
1 km/h = 0.27778 m/s
1 m/s = 3.6 km/h
Examples:
Speed | In m/s |
---|---|
10 km/h | 2.78 m/s |
50 km/h | 13.89 m/s |
100 km/h | 27.78 m/s |
Kilometers per Hour to Miles per Hour
Conversion:
1 km/h ≈ 0.6214 mph
1 mph ≈ 1.609 km/h
Examples:
Speed (km/h) | Speed (mph) |
---|---|
10 | 6.21 |
60 | 37.28 |
100 | 62.14 |
120 | 74.56 |
Knots to Kilometers and Miles per Hour
A knot is one nautical mile per hour.
- 1 knot = 1.852 km/h ≈ 1.15078 mph
- 1 km/h = 0.53996 knots
Examples:
Knots | km/h | mph |
---|---|---|
10 | 18.52 | 11.51 |
20 | 37.04 | 23.02 |
30 | 55.56 | 34.54 |
50 | 92.6 | 57.54 |
Meters per Second to Kilometers per Hour
A helpful conversion in athletics or physics:
1 m/s = 3.6 km/h
Examples:
Speed (m/s) | Speed (km/h) |
---|---|
2 | 7.2 |
5 | 18 |
10 | 36 |
15 | 54 |
Quick Speed Conversion Table
Unit | Converts To |
---|---|
1 km/h | 0.27778 m/s = 0.6214 mph = 0.53996 knots |
1 mph | 1.609 km/h |
1 m/s | 3.6 km/h |
1 knot | 1.852 km/h = 1.15078 mph |
Time Conversion
Time units are part of nearly every activity — from setting alarms and measuring work hours to calculating project timelines or understanding how long a year truly is. The basics are well-known, but once you start multiplying hours into days, months into minutes, or years into seconds — things get interesting. Let’s explore these conversions step by step.
Fundamental Time Units
- 1 minute = 60 seconds
- 1 hour = 60 minutes = 3,600 seconds
- 1 day = 24 hours = 1,440 minutes = 86,400 seconds
- 1 week = 7 days
- 1 year = 365 days (366 in leap years)
Time Breakdown (Non-Leap Year)
Unit | Value |
---|---|
1 day | 24 hours / 1,440 minutes / 86,400 seconds |
1 week | 168 hours / 10,080 minutes / 604,800 sec |
1 month (avg) | ~30.44 days ≈ 730.5 hours |
1 year | 365 days / 8,760 hours / 525,600 minutes |
1 year (sec) | 31,536,000 seconds |
Leap Year Time
A leap year has one extra day:
- 366 days = 8,784 hours = 527,040 minutes = 31,622,400 seconds
Practical Examples
Time Frame | In Hours | In Minutes | In Seconds |
---|---|---|---|
2.5 hours | 2.5 | 150 | 9,000 |
3 days | 72 | 4,320 | 259,200 |
1 week | 168 | 10,080 | 604,800 |
1 month (30 days) | 720 | 43,200 | 2,592,000 |
Working Days in a Year
Typically:
- ~250 workdays per year (varies by country and holidays)
- That equals roughly:
- 2,000 work hours
- 120,000 work minutes
Time Conversion Table
Unit | Equivalent |
---|---|
1 minute | 60 seconds |
1 hour | 60 minutes = 3,600 seconds |
1 day | 24 hours = 1,440 minutes = 86,400 seconds |
1 week | 7 days = 168 hours |
1 year | 365 days = 8,760 hours |
Leap year | 366 days = 8,784 hours |
Angle Conversion
Angles are used to describe rotation, direction, or shape — whether you’re measuring corners in geometry, turning a car’s steering wheel, or navigating with a compass. The two most common units are degrees (°) and radians (rad). Let’s look at how they relate and how to convert between them.
Degrees
Degrees divide a full circle into 360 equal parts:
- A right angle = 90°
- A straight line = 180°
- A full circle = 360°
Degrees are widely used in daily life, from architecture to sports.
Radians
Radians are used more often in scientific, engineering, and programming contexts. They’re based on the arc length of a circle:
- One full circle = 2π radians ≈ 6.2832 rad
- Half circle = π radians ≈ 3.1416 rad
This system simplifies formulas in trigonometry and calculus.
Conversion Formulas
- To convert degrees to radians:
radians = degrees × (π / 180) - To convert radians to degrees:
degrees = radians × (180 / π)
Examples: Degrees to Radians
Degrees (°) | Formula | Radians (rad) |
---|---|---|
30° | 30 × π / 180 | π/6 ≈ 0.5236 |
45° | 45 × π / 180 | π/4 ≈ 0.7854 |
90° | 90 × π / 180 | π/2 ≈ 1.5708 |
180° | 180 × π / 180 | π ≈ 3.1416 |
360° | 360 × π / 180 | 2π ≈ 6.2832 |
Examples: Radians to Degrees
Radians (rad) | Formula | Degrees (°) |
---|---|---|
π/6 ≈ 0.5236 | 0.5236 × (180 / π) | 30° |
π/2 ≈ 1.5708 | 1.5708 × (180 / π) | 90° |
1 rad | 1 × (180 / π) | ≈ 57.3° |
2 rad | 2 × (180 / π) | ≈ 114.6° |
Quick Angle Conversion Table
Degrees (°) | Radians (rad) |
---|---|
0° | 0 |
30° | π/6 ≈ 0.5236 |
45° | π/4 ≈ 0.7854 |
90° | π/2 ≈ 1.5708 |
180° | π ≈ 3.1416 |
360° | 2π ≈ 6.2832 |
Pressure Conversion
Pressure is the force applied per unit area. We encounter it in many situations: checking tire pressure, reading weather maps, adjusting espresso machines, or measuring blood pressure. Various units are used across different industries and countries, so converting between them is often necessary.
Common Pressure Units
- Pascal (Pa) – SI unit of pressure
- Kilopascal (kPa) – commonly used in engineering
- Bar – popular in automotive, technical, and espresso machines
- Atmosphere (atm) – standard reference pressure
- Millimeters of mercury (mmHg) – often used in medicine
- Pounds per square inch (psi) – widely used in the US
Pascal-Based Units
- 1 kPa = 1,000 Pa
- 1 MPa = 1,000,000 Pa
Standard atmospheric pressure at sea level:
- 1 atm = 101,325 Pa = 101.325 kPa
Conversions Between Units
Unit | Equivalent |
---|---|
1 atm | 101,325 Pa = 101.325 kPa ≈ 1.013 bar |
1 bar | 100,000 Pa = 100 kPa ≈ 0.9869 atm |
1 psi | 6,894.76 Pa ≈ 0.06895 bar |
1 mmHg | 133.322 Pa ≈ 0.00131579 atm |
1 kPa | 0.145 psi ≈ 0.009869 atm |
Examples: Converting to Bar
Value | In Bar |
---|---|
100,000 Pa | 1 bar |
202,650 Pa | 2.0265 bar |
1 atm | ≈ 1.013 bar |
30 psi | ≈ 2.07 bar |
Examples: psi to kPa and atm
psi | kPa | atm |
---|---|---|
14.7 | 101.325 | 1.0 |
32 | ≈ 220.6 | ≈ 2.18 |
50 | ≈ 344.7 | ≈ 3.4 |
Quick Pressure Conversion Table
Unit | Converts To |
---|---|
1 atm | 101.325 kPa = 1.013 bar = 14.7 psi |
1 bar | 100 kPa = 0.9869 atm = 14.5 psi |
1 psi | 6.89476 kPa = 0.0689 bar |
1 mmHg | 133.322 Pa = 0.001316 atm |
Energy and Power Conversion
Energy tells us how much work can be done, and power tells us how fast that energy is used. You see energy units on food labels, electricity bills, engine specs, and fitness trackers. The most common units include joules, calories, kilowatt-hours, watts, and horsepower.
Energy Units
- Joule (J) — SI base unit of energy
- Kilojoule (kJ) = 1,000 J
- Calorie (cal) — used in chemistry and food science
- Kilocalorie (kcal) = 1,000 cal — often called “calorie” on nutrition labels
- Kilowatt-hour (kWh) — used in electricity billing
Power Units
- Watt (W) — unit of power: 1 watt = 1 joule per second
- Kilowatt (kW) = 1,000 W
- Horsepower (hp) — still used in automotive specs
- 1 metric hp ≈ 735.5 W
- 1 mechanical hp ≈ 745.7 W
Energy Conversions
Unit | Equivalent |
---|---|
1 cal | 4.184 J |
1 kcal | 1,000 cal = 4,184 J = 4.184 kJ |
1 kWh | 3.6 million J = 3,600,000 J = 860 kcal |
1 J | 0.000278 kWh ≈ 0.239 cal |
Examples
Value | Converted Energy |
---|---|
100 kcal | 418,400 J |
1 kWh | 3,600,000 J = 860 kcal |
500 kJ | ≈ 119.5 kcal |
Power Conversions
Unit | Equivalent |
---|---|
1 W | 1 J/s |
1 kW | 1,000 W |
1 hp (metric) | 735.5 W |
1 hp (mechanical) | 745.7 W |
Examples
Power Rating | Description |
---|---|
1,500 W heater | 1.5 kW — uses 1.5 kWh per hour |
100 hp engine | ≈ 73.5 kW |
60 W lightbulb | 0.06 kW — 0.06 kWh in one hour |
Quick Conversion Summary
From | To |
---|---|
1 kcal | 4.184 kJ |
1 kWh | 860 kcal = 3.6 MJ |
1 J | 0.000239 kcal = 2.78 × 10⁻⁷ kWh |
1 hp | ≈ 0.7355 kW (metric) or 0.7457 kW (US) |
Measurement units are the foundation of how we understand and interact with the world — from tracking time and distance to managing energy, weight, and digital data. This guide walked you through the essential categories of conversion:
- Temperature, to help you interpret weather, cooking, and lab results
- Length and Area, to measure spaces, objects, and land
- Volume, to compare liquids in kitchens or tanks
- Weight, for health, trade, and logistics
- Speed, whether in sports, travel, or navigation
- Time, as it relates to productivity, planning, and science
- Angles, used in geometry, physics, and design
- Pressure, found in weather reports, machines, and medicine
- Energy and Power, for food labels, electricity, and engines
By understanding how to move between units with confidence, you gain control — whether you’re solving technical problems, making smart purchases, interpreting global standards, or just getting through everyday tasks more smoothly.
Keep this guide handy — and let it serve as your reliable reference in a world full of numbers.
FAQ
1. What is 200°C in Fahrenheit?
To convert Celsius to Fahrenheit, use the formula:
(200 × 9/5) + 32 = 392°F
So, 200°C = 392°F — a common baking temperature for roasting.
2. How many feet are there in a mile?
There are 5,280 feet in one mile. This is a fixed value used in both running events and land measurement in the U.S.
3. How do I convert a decimal to a fraction?
To convert a decimal like 0.75 into a fraction:
0.75 = 75/100 = 3/4 (simplified).
The process involves removing the decimal by multiplying and simplifying the fraction.
4. What is 25°C in Fahrenheit?
25°C × 9/5 + 32 = 77°F
So, a temperature of 25°C feels like a warm day: 77°F.
5. What time is it in Los Angeles right now?
Los Angeles is in the Pacific Time Zone (PT). To know the exact time, check a live clock. When it’s 12:00 in New York (ET), it’s usually 09:00 in LA (PT), except during daylight saving transitions.
6. How many seconds are there in a year?
A non-leap year has:
365 × 24 × 60 × 60 = 31,536,000 seconds
A leap year has 31,622,400 seconds.
7. How many ounces are in a pound?
There are 16 ounces (oz) in 1 pound (lb).
This is used in cooking, postal services, and body weight.
8. How tall is 170 cm in feet and inches?
To convert centimeters to feet:
170 cm ÷ 30.48 ≈ 5.577 ft, or about 5 feet 7 inches.
9. How many millimeters are in an inch?
1 inch = 25.4 millimeters.
So, to convert mm to inches: divide by 25.4.
Example: 40 mm ≈ 1.57 inches
10. How many liters are in a gallon?
It depends on the system:
- 1 US gallon = 3.785 liters
- 1 UK (Imperial) gallon = 4.546 liters