How to Do Common Conversions Manually – Easy Step-by-Step Guide

Need help figuring out measurements or numbers without a calculator or converter? These simple, step-by-step guides will show you how to do common conversions by hand. Each one is easy to follow—no complicated math, just clear instructions and examples!

How to Find What Percentage One Number Is of Another

Want to know what percent 25 is of 200?

Step-by-step:
Divide the smaller number by the larger number:

25 ÷ 200 = 0.125

Multiply the result by 100:

0.125 × 100 = 12.5%

So, 25 is 12.5% of 200.

How to Calculate a Percentage of a Number

What is 30% of 80?

Step-by-step:
Change the percent to a decimal:

30% = 0.30

Multiply the decimal by the number:

0.30 × 80 = 24

So, 30% of 80 is 24.

How to Convert Kilometers to Miles

Want to convert 10 kilometers to miles?

1 kilometer = 0.6214 miles

Step-by-step:
Multiply the kilometers by 0.6214:

10 × 0.6214 = 6.214

So, 10 kilometers is about 6.21 miles.

How to Convert Miles to Kilometers

Trying to convert 5 miles to kilometers?

1 mile = 1.6093 kilometers

Step-by-step:
Multiply the miles by 1.6093:

5 × 1.6093 = 8.0465

So, 5 miles is about 8.05 kilometers.

How to Convert Pounds to Kilograms

Want to know how many kilograms are in 150 pounds?

1 pound = 0.4536 kilograms

Step-by-step:
Multiply the pounds by 0.4536:

150 × 0.4536 = 68.04

So, 150 pounds is about 68.04 kilograms.

How to Convert Kilograms to Pounds

Want to convert 50 kilograms to pounds?

1 kilogram = 2.2046 pounds

Step-by-step:
Multiply the kilograms by 2.2046:

50 × 2.2046 = 110.23

So, 50 kilograms is about 110.23 pounds.

How to Convert Celsius to Fahrenheit

Want to convert 20°C to Fahrenheit?

Use this formula:
Fahrenheit = (Celsius × 1.8) + 32

Step-by-step:
Multiply 20 × 1.8 = 36

Add 32: 36 + 32 = 68

So, 20°C is 68°F.

How to Convert Fahrenheit to Celsius

Trying to convert 77°F to Celsius?

Use this formula:
Celsius = (Fahrenheit − 32) ÷ 1.8

Step-by-step:
Subtract 32: 77 − 32 = 45

Divide by 1.8: 45 ÷ 1.8 = 25

So, 77°F is 25°C.

How to Convert Minutes to Hours

How many hours is 150 minutes?

Step-by-step:
Divide the minutes by 60:

150 ÷ 60 = 2.5

So, 150 minutes is 2.5 hours (or 2 hours and 30 minutes).

How to Convert Liters to Milliliters

Need to convert 3 liters to milliliters?

1 liter = 1,000 milliliters

Step-by-step:
Multiply the liters by 1,000:

3 × 1,000 = 3,000

So, 3 liters = 3,000 milliliters.

How to Convert Inches to Centimeters

Want to know how long 12 inches is in centimeters?

1 inch = 2.54 centimeters

Step-by-step:
Multiply the inches by 2.54:

12 × 2.54 = 30.48

So, 12 inches is 30.48 centimeters.

How to Convert Centimeters to Inches

Trying to convert 50 centimeters to inches?

1 centimeter = 0.3937 inches

Step-by-step:
Multiply the centimeters by 0.3937:

50 × 0.3937 = 19.685

So, 50 centimeters is about 19.69 inches.

How to Convert a Decimal to a Percentage

Want to turn 0.75 into a percent?

Step-by-step:
Multiply the decimal by 100:

0.75 × 100 = 75

Add a % sign:

75%

So, 0.75 = 75%.

How to Convert a Fraction to a Percentage

What percent is ⅘?

Step-by-step:
Divide the top number by the bottom:

4 ÷ 5 = 0.8

Multiply by 100:

0.8 × 100 = 80

So, ⅘ is 80%.

Want More?

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