Circumference & Areas
| Size in Inches |
Circumference Inches |
Area in Square Inches |
Area in Square Inches |
Size in Inches |
Circumference Inches |
Area in Square Inches |
Area in Square Inches |
| 1/4 |
0.785 |
0.049 |
0.063 |
10 1/4 |
32.200 |
82.520 |
105.060 |
| 1/2 |
1.571 |
0.196 |
0.250 |
10 1/2 |
32.990 |
86.590 |
110.250 |
| 3/4 |
2.356 |
0.442 |
0.563 |
10 3/4 |
33.770 |
90.760 |
115.560 |
| 1 |
3.142 |
0.785 |
1.000 |
11 |
34.560 |
95.030 |
121.000 |
| 1 1/4 |
3.927 |
1.227 |
1.563 |
11 1/4 |
35.340 |
99.400 |
126.560 |
| 1 1/2 |
4.712 |
1.767 |
2.250 |
11 1/2 |
36.130 |
103.870 |
132.250 |
| 1 3/4 |
5.498 |
2.405 |
3.063 |
11 3/4 |
36.910 |
108.430 |
138.060 |
| 2 |
6.283 |
3.142 |
4.000 |
12 |
37.700 |
113.100 |
144.000 |
| 2 1/4 |
7.069 |
3.976 |
5.063 |
12 1/4 |
38.480 |
117.860 |
150.060 |
| 2 1/2 |
7.854 |
4.909 |
6.250 |
12 1/2 |
39.270 |
122.720 |
156.250 |
| 2 3/4 |
8.639 |
5.940 |
7.563 |
12 3/4 |
40.060 |
127.680 |
162.560 |
| 3 |
9.425 |
7.069 |
9.000 |
13 |
40.840 |
132.730 |
169.000 |
| 3 1/4 |
10.210 |
8.296 |
10.560 |
13 1/4 |
41.630 |
137.890 |
175.560 |
| 3 1/2 |
11.000 |
9.621 |
12.250 |
13 1/2 |
42.410 |
143.140 |
182.250 |
| 3 3/4 |
11.780 |
11.040 |
14.060 |
13 3/4 |
43.200 |
148.490 |
189.060 |
| 4 |
12.570 |
12.470 |
16.000 |
14 |
43.980 |
153.940 |
196.000 |
| 4 1/4 |
13.350 |
14.190 |
18.060 |
14 1/4 |
44.770 |
159.490 |
209.060 |
| 4 1/2 |
14.140 |
15.900 |
20.250 |
14 1/2 |
45.550 |
165.130 |
210.250 |
| 4 3/4 |
14.920 |
17.720 |
22.560 |
14 3/4 |
46.340 |
170.870 |
217.560 |
| 5 |
15.710 |
19.640 |
25.000 |
15 |
47.120 |
176.720 |
225.000 |
| 5 1/4 |
16.490 |
21.650 |
27.560 |
15 1/4 |
47.910 |
182.650 |
232.560 |
| 5 1/2 |
17.280 |
23.760 |
30.250 |
15 1/2 |
48.690 |
188.690 |
240.250 |
| 5 3/4 |
18.060 |
25.970 |
33.060 |
15 3/4 |
49.480 |
194.830 |
248.060 |
| 6 |
18.850 |
28.270 |
36.000 |
16 |
50.270 |
201.060 |
256.000 |
| 6 1/4 |
19.640 |
30.680 |
39.060 |
16 1/4 |
51.050 |
207.390 |
264.060 |
| 6 1/2 |
20.420 |
33.180 |
42.250 |
16 1/2 |
51.840 |
213.830 |
272.250 |
| 6 3/4 |
21.210 |
35.780 |
45.560 |
16 3/4 |
53.620 |
220.350 |
280.560 |
| 7 |
21.990 |
38.480 |
49.000 |
17 |
53.410 |
226.980 |
289.000 |
| 7 1/4 |
22.780 |
41.280 |
52.560 |
17 1/4 |
54.190 |
233.710 |
297.560 |
| 7 1/2 |
23.560 |
44.180 |
56.250 |
17 1/2 |
54.980 |
240.530 |
306.250 |
| 7 3/4 |
24.350 |
47.170 |
60.060 |
17 3/4 |
55.760 |
247.450 |
315.060 |
| 8 |
25.130 |
50.270 |
64.000 |
18 |
56.550 |
254.470 |
324.000 |
| 8 1/4 |
25.920 |
53.460 |
68.060 |
18 1/4 |
57.330 |
261.590 |
333.060 |
| 8 1/2 |
26.700 |
56.750 |
72.250 |
18 1/2 |
58.120 |
268.800 |
342.250 |
| 8 3/4 |
27.490 |
60.130 |
76.560 |
18 3/4 |
58.910 |
276.120 |
351.560 |
| 9 |
28.280 |
63.620 |
81.000 |
19 |
59.690 |
283.530 |
361.000 |
| 9 1/4 |
29.060 |
67.200 |
85.560 |
19 1/4 |
60.480 |
291.040 |
370.560 |
| 9 1/2 |
29.850 |
70.880 |
90.250 |
19 1/2 |
61.260 |
298.650 |
380.250 |
| 9 3/4 |
30.630 |
74.660 |
95.060 |
19 3/4 |
62.050 |
306.360 |
390.060 |
| 10 |
31.420 |
78.540 |
100.000 |
20 |
62.830 |
314.160 |
400.000 |
Rules Relating to Circles and Ovals
- The circumference of a circle is the diameter x 3.1416.
- The diameter of a circle is the circumference multiplied by 0.31831.
- The area of a circle is the diameter x diameter x 0.7854.
- The area of an oval is the longest diameter x the shortest x 0.7854.
- A circle is 0.7854 times as heavy as a square of the same size.
