Size (Imperial)

Surface area

Size (Metric)

Surface area

Ratio of Sides

percentage of 35mm frame

Inches

sq inches

centimetres

sq cms

approximate

3½ X 5

17½

8.9 X 12.7

113.03

1:1.43

95%

6 X 4

24

15.2 X 10.2

155.04

1:1.5

100%

5 X 7

35

12.7 X 17.8

226.06

1:1.4

93%

8 X 6

48

20.3 X 15.2

354.16

1:1.3

85%

A5

49½

21 X 14.9

312.9

1:1.41

93%

10 X 8

80

25.4 X 20.3

515.62

1:1.25

83%

A4

97

29.7 X 21

623.7

1:1.41

93%

12 X 10

120

30.5 X 25.4

774.7

1:1.2

80%

A3

194

42 X 29.7

1247.4

1:1.41

93%

16 X 12

192

40.6 X 30.5

1238.3

1:1.33

90%

20 X 16

320

50.8 X 40.6

2062.48

1:1.25

83%

A2

379½

58.4 X 42

2452.8

1:1.39

93%

20 X 24

480

61 X 50.8

3098.8

1:1.2

80%

A1

759

84.1 X 58.4

4911.44

1:1.44

N/A

20 X 30

600

76.2 X 50.8

3870.96

1:1.5

N/A

30 X 40

1200

101.6 X 76.2

7741.92

1:1.33

N/A