Circumference of a Circle Calculator

Circle Calculator

Circumference Area

Inputs:

Radius (r):		or
Diameter (d):		or
Area (A):
Unit of Lenght:

The circumference of a circle with radius 5 is 31.42(*)

Formulas:

C = 2·π·r

C = π·d

C = √4·π·A

π = 3.1415
A = area of the circle
C = circumference or perimeter
r = radius, d = diameter

Step-by-step Solution:

Circumference of a cicle in terms of radius:

Circumference = 2·π·r = 2·3.14·5 = 31.42^(*)

In terms of diameter:

Circumference = π·d = 3.14·10 = 31.4^(*)

In terms of area:

Circumference C = √4·π·A = √4·π·78.54 = 31.42^(*)

^(*) 31.42 meters exactly or limited to de precision of this calculator (13 decimal places).

Note: for simplicity, the operations above were rounded to 2 decimal places and π was rounded to 3.14.

Use the this circumference length calculator above to find the perimeter of a circle given its radius, or other parameters.

Formula to calculate the circumference of a circle

Here a three ways to find the circumference or perimeter of a circle:

Circumference length formula in terms of radius

C = 2·π·r

Circumference length formula in terms of diameter

C = π·d

Circumference length formula in terms of area

C = √4·π·A

Questions this calculator can answer:

How to find the perimeter of a circle with a radius of 5 meters?
A circle has a diameter of 10 meters. What is its circumference?
If a circle has a area of 78.54 square meters. What is its perimeter?

Relation between radius, diameter, area and circumference of a circle

Note: All values are rounded to two decimal places.

Radius	Diameter	Area	Circumference
0.1	0.2	0.03	0.63
0.15	0.3	0.07	0.94
0.2	0.4	0.13	1.26
0.25	0.5	0.2	1.57
0.3	0.6	0.28	1.88
0.35	0.7	0.38	2.2
0.4	0.8	0.5	2.51
0.45	0.9	0.64	2.83
0.5	1	0.79	3.14
0.55	1.1	0.95	3.46
0.6	1.2	1.13	3.77
0.65	1.3	1.33	4.08
0.7	1.4	1.54	4.4
0.75	1.5	1.77	4.71
0.8	1.6	2.01	5.03
0.85	1.7	2.27	5.34
0.9	1.8	2.54	5.65
0.95	1.9	2.83	5.97
1	2	3.14	6.28
1.01	2.02	3.2	6.35
1.02	2.04	3.27	6.41
1.03	2.06	3.33	6.47
1.04	2.08	3.4	6.53
1.05	2.1	3.46	6.6
1.06	2.12	3.53	6.66
1.07	2.14	3.59	6.72
1.08	2.16	3.66	6.79
1.09	2.18	3.73	6.85
1.1	2.2	3.8	6.91
1.10	2.2	3.8	6.91
1.11	2.22	3.87	6.97
1.12	2.24	3.94	7.04
1.13	2.26	4.01	7.1
1.14	2.28	4.08	7.16
1.15	2.3	4.15	7.23
1.16	2.32	4.23	7.29
1.17	2.34	4.3	7.35
1.18	2.36	4.37	7.41
1.19	2.38	4.45	7.48
1.2	2.4	4.52	7.54
1.20	2.4	4.52	7.54
1.21	2.42	4.6	7.6
1.22	2.44	4.67	7.67
1.23	2.46	4.75	7.73
1.24	2.48	4.83	7.79
1.25	2.5	4.91	7.85
1.26	2.52	4.99	7.92
1.27	2.54	5.06	7.98
1.28	2.56	5.14	8.04
1.29	2.58	5.23	8.11
1.3	2.6	5.31	8.17
1.30	2.6	5.31	8.17
1.31	2.62	5.39	8.23
1.32	2.64	5.47	8.29
1.33	2.66	5.55	8.36
1.34	2.68	5.64	8.42
1.35	2.7	5.72	8.48
1.36	2.72	5.81	8.54
1.37	2.74	5.89	8.61
1.38	2.76	5.98	8.67
1.39	2.78	6.07	8.73
1.4	2.8	6.15	8.8
1.40	2.8	6.15	8.8
1.41	2.82	6.24	8.86
1.42	2.84	6.33	8.92
1.43	2.86	6.42	8.98
1.44	2.88	6.51	9.05
1.45	2.9	6.6	9.11
1.46	2.92	6.69	9.17
1.47	2.94	6.79	9.24
1.48	2.96	6.88	9.3
1.49	2.98	6.97	9.36
1.5	3	7.07	9.42
1.50	3	7.07	9.42
1.51	3.02	7.16	9.49
1.52	3.04	7.25	9.55
1.53	3.06	7.35	9.61
1.54	3.08	7.45	9.68
1.55	3.1	7.54	9.74
1.56	3.12	7.64	9.8
1.57	3.14	7.74	9.86
1.58	3.16	7.84	9.93
1.59	3.18	7.94	9.99
1.6	3.2	8.04	10.05
1.60	3.2	8.04	10.05
1.61	3.22	8.14	10.12
1.62	3.24	8.24	10.18
1.63	3.26	8.34	10.24
1.64	3.28	8.45	10.3
1.65	3.3	8.55	10.37
1.66	3.32	8.65	10.43
1.67	3.34	8.76	10.49
1.68	3.36	8.86	10.56
1.69	3.38	8.97	10.62
1.7	3.4	9.07	10.68
1.70	3.4	9.07	10.68
1.71	3.42	9.18	10.74
1.72	3.44	9.29	10.81
1.73	3.46	9.4	10.87
1.74	3.48	9.51	10.93
1.75	3.5	9.62	11
1.76	3.52	9.73	11.06
1.77	3.54	9.84	11.12
1.78	3.56	9.95	11.18
1.79	3.58	10.06	11.25
1.8	3.6	10.17	11.31
1.80	3.6	10.17	11.31
1.81	3.62	10.29	11.37
1.82	3.64	10.4	11.44
1.83	3.66	10.52	11.5
1.84	3.68	10.63	11.56
1.85	3.7	10.75	11.62
1.86	3.72	10.86	11.69
1.87	3.74	10.98	11.75
1.88	3.76	11.1	11.81
1.89	3.78	11.22	11.87
1.9	3.8	11.34	11.94
1.90	3.8	11.34	11.94
1.91	3.82	11.46	12
1.92	3.84	11.58	12.06
1.93	3.86	11.7	12.13
1.94	3.88	11.82	12.19
1.95	3.9	11.94	12.25
1.96	3.92	12.06	12.31

Radius	Diameter	Area	Circumference
1.97	3.94	12.19	12.38
1.98	3.96	12.31	12.44
1.99	3.98	12.43	12.5
2	4	12.56	12.57
2.00	4	12.56	12.57
2.01	4.02	12.69	12.63
2.02	4.04	12.81	12.69
2.03	4.06	12.94	12.75
2.04	4.08	13.07	12.82
2.05	4.1	13.2	12.88
2.06	4.12	13.32	12.94
2.07	4.14	13.45	13.01
2.08	4.16	13.58	13.07
2.09	4.18	13.72	13.13
2.1	4.2	13.85	13.19
2.10	4.2	13.85	13.19
2.11	4.22	13.98	13.26
2.12	4.24	14.11	13.32
2.13	4.26	14.25	13.38
2.14	4.28	14.38	13.45
2.15	4.3	14.51	13.51
2.16	4.32	14.65	13.57
2.17	4.34	14.79	13.63
2.18	4.36	14.92	13.7
2.19	4.38	15.06	13.76
2.2	4.4	15.2	13.82
2.20	4.4	15.2	13.82
2.21	4.42	15.34	13.89
2.22	4.44	15.48	13.95
2.23	4.46	15.61	14.01
2.24	4.48	15.76	14.07
2.25	4.5	15.9	14.14
2.26	4.52	16.04	14.2
2.27	4.54	16.18	14.26
2.28	4.56	16.32	14.33
2.29	4.58	16.47	14.39
2.3	4.6	16.61	14.45
2.30	4.6	16.61	14.45
2.31	4.62	16.76	14.51
2.32	4.64	16.9	14.58
2.33	4.66	17.05	14.64
2.34	4.68	17.19	14.7
2.35	4.7	17.34	14.77
2.36	4.72	17.49	14.83
2.37	4.74	17.64	14.89
2.38	4.76	17.79	14.95
2.39	4.78	17.94	15.02
2.4	4.8	18.09	15.08
2.40	4.8	18.09	15.08
2.41	4.82	18.24	15.14
2.42	4.84	18.39	15.2
2.43	4.86	18.54	15.27
2.44	4.88	18.69	15.33
2.45	4.9	18.85	15.39
2.46	4.92	19	15.46
2.47	4.94	19.16	15.52
2.48	4.96	19.31	15.58
2.49	4.98	19.47	15.64
2.5	5	19.63	15.71
2.50	5	19.63	15.71
2.51	5.02	19.78	15.77
2.52	5.04	19.94	15.83
2.53	5.06	20.1	15.9
2.54	5.08	20.26	15.96
2.55	5.1	20.42	16.02
2.56	5.12	20.58	16.08
2.57	5.14	20.74	16.15
2.58	5.16	20.9	16.21
2.59	5.18	21.06	16.27
2.6	5.2	21.23	16.34
2.60	5.2	21.23	16.34
2.61	5.22	21.39	16.4
2.62	5.24	21.55	16.46
2.63	5.26	21.72	16.52
2.64	5.28	21.88	16.59
2.65	5.3	22.05	16.65
2.66	5.32	22.22	16.71
2.67	5.34	22.38	16.78
2.68	5.36	22.55	16.84
2.69	5.38	22.72	16.9
2.7	5.4	22.89	16.96
2.70	5.4	22.89	16.96
2.71	5.42	23.06	17.03
2.72	5.44	23.23	17.09
2.73	5.46	23.4	17.15
2.74	5.48	23.57	17.22
2.75	5.5	23.75	17.28
2.76	5.52	23.92	17.34
2.77	5.54	24.09	17.4
2.78	5.56	24.27	17.47
2.79	5.58	24.44	17.53
2.8	5.6	24.62	17.59
2.80	5.6	24.62	17.59
2.81	5.62	24.79	17.66
2.82	5.64	24.97	17.72
2.83	5.66	25.15	17.78
2.84	5.68	25.33	17.84
2.85	5.7	25.5	17.91
2.86	5.72	25.68	17.97
2.87	5.74	25.86	18.03
2.88	5.76	26.04	18.1
2.89	5.78	26.23	18.16
2.9	5.8	26.41	18.22
2.90	5.8	26.41	18.22
2.91	5.82	26.59	18.28
2.92	5.84	26.77	18.35
2.93	5.86	26.96	18.41
2.94	5.88	27.14	18.47
2.95	5.9	27.33	18.53
2.96	5.92	27.51	18.6
2.97	5.94	27.7	18.66
2.98	5.96	27.88	18.72
2.99	5.98	28.07	18.79
3	6	28.26	18.85
3.00	6	28.26	18.85
3.01	6.02	28.45	18.91
3.02	6.04	28.64	18.97
3.03	6.06	28.83	19.04
3.04	6.08	29.02	19.1
3.05	6.1	29.21	19.16
3.06	6.12	29.4	19.23
3.07	6.14	29.59	19.29
3.08	6.16	29.79	19.35
3.09	6.18	29.98	19.41
3.1	6.2	30.18	19.48

Popular Circumference Calculations

Calculate circumference for different circle dimensions:

Related Calculators

Circle Area Calculator — area from radius or diameter
Cube Root Calculator — inverse of cubing for 3D problems
Decimal to Percent — convert ratios to percentages