Diameter to Circumference Calculator

Diameter and circumference defined by the formula C = πd, where π is equal to 3.14159, our diameter to circumference calculator helps convert the circumference of a circle when given its diameter.

We have a circle with a diameter of 10 units, we can use the calculator to find that its circumference is approximately 31.42 units.

Diameter to Circumference Calculator

Inches Diameter to	Circumference (inches)
1 inch	3.14 inches
1.5 inches	4.71 inches
2 inches	6.28 inches
2.5 inches	7.85 inches
3 inches	9.42 inches
3.5 inches	10.99 inches
4 inches	12.57 inches
4.5 inches	14.14 inches
5 inches	15.71 inches
5.5 inches	17.28 inches
6 inches	18.85 inches
6.5 inches	20.42 inches
7 inches	21.99 inches
7.5 inches	23.56 inches
8 inches	25.13 inches
8.5 inches	26.70 inches
9 inches	28.27 inches
9.5 inches	29.84 inches
10 inches	31.42 inches
10.5 inches	32.99 inches
11 inches	34.56 inches
11.5 inches	36.13 inches
12 inches	37.70 inches
12.5 inches	39.27 inches
13 inches	40.84 inches
13.5 inches	42.41 inches
14 inches	43.98 inches
14.5 inches	45.55 inches
15 inches	47.12 inches
15.5 inches	48.69 inches
16 inches	50.27 inches
16.5 inches	51.84 inches
17 inches	53.41 inches
17.5 inches	54.98 inches
18 inches	56.55 inches
18.5 inches	58.12 inches
19 inches	59.69 inches
19.5 inches	61.26 inches
20 inches	62.83 inches

Diameter to Circumference Chart

Diameter	Circumference
1 cm	3.14 cm
2 cm	6.28 cm
3 in	9.42 in
4 ft	12.57 ft
5 m	15.71 m
6 mm	18.85 mm
7 km	21.99 km
8 mi	25.13 mi
9 yd	28.27 yd
10 cm	31.42 cm
11 in	34.56 in
12 ft	37.70 ft
13 m	40.84 m
14 mm	43.98 mm
15 km	47.12 km
16 mi	50.27 mi
17 yd	53.41 yd
18 cm	56.55 cm
19 in	59.69 in
20 ft	62.83 ft

This chart provides comprehensive reference for converting between diameter and circumference for various units of measurement, including centimeters (cm), inches (in), feet (ft), meters (m), millimeters (mm), kilometers (km), miles (mi), and yards (yd).

Diameter to Circumference Formula

The formula to calculate the circumference (C) of a circle from its diameter (d) is:

C = πd

Where π (pi) is approximately equal to 3.14159.

For a circle with a diameter of 7 units: C = π 7 ≈ **3.14159 7 ≈ 21.99 units**

If the diameter is 15 cm: C = π 15 ≈ **3.14159 15 ≈ 47.12 cm**

How do you convert diameter to circumference?

• Identify the diameter: Measure or note the given diameter of the circle.
• Multiply by π: Multiply the diameter by π (3.14159).
• Round if necessary: Round the result to the desired number of decimal places.

Let’s convert a diameter of 12 inches to circumference.

Diameter = 12 inches

Multiply by π: 12 * 3.14159 = 37.69908 inches

Rounding to two decimal places: 37.70 inches

The circumference of a circle with a 12-inch diameter is approximately 37.70 inches.

Is diameter 2 times the circumference?

No, the diameter is not 2 times the circumference. In fact, it’s the other way around: the circumference is approximately 3.14159 (π) times the diameter.

Explanation:

• Circumference = πd
• Diameter = C / π

If the diameter were 2 times the circumference, we would have: d = 2C
C = πd = π(2C) = 2πC

This would imply that π = 1/2, which is incorrect. The actual value of π is approximately 3.14159, not 0.5.

What is the circumference of a 20 inch diameter circle?

Rounded to two decimal places, the circumference is 62.83 inches.

To find the circumference of a 20-inch diameter circle:

1. Use the formula: C = πd
2. Plug in the values: C = π * 20
3. Calculate: C ≈ 3.14159 * 20 ≈ 62.83 inches

Detailed calculation: C = 3.14159265358979 * 20 = 62.8318530717959 inches

What is the circumference of a 5 ft diameter circle?

Rounded to two decimal places, the circumference is 15.71 feet.

For a circle with a 5 ft diameter:

1. Apply the formula: C = πd
2. Insert the values: C = π * 5 ft
3. Compute: C ≈ 3.14159 * 5 ≈ 15.71 ft

Detailed calculation: C = 3.14159265358979 * 5 = 15.7079632679489 ft

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