C series (envelopes) to A series
Type a value in C to get it in A instantly.
≈A3A
That's 1.19× as big as an A3 sheet, while an A1 poster is 3.4× bigger. With ISO proportions that is a sheet of about 324.2 × 458.5 mm (12.76 × 18.05 in).
What it means
How big is that sheet?
ISO 216 sizes are rounded to whole millimeters on real sheets. US sizes are compared by area; their proportions differ from √2.
The math
How to convert C to A
Area of A n = 2^−n m²; B n = 2^(½−n) m², C n = 2^(¼−n) m². Sides are in the ratio 1 : √2.
Example: C3 C = ≈A3 A.
Every unit
That sheet in every system
Tables
C to A conversion table
| C | A |
|---|---|
| C0 C | ≈A0 A |
| C1 C | ≈A1 A |
| C2 C | ≈A2 A |
| C3 C | ≈A3 A |
| C4 C | ≈A4 A |
| C5 C | ≈A5 A |
| C6 C | ≈A6 A |
| C7 C | ≈A7 A |
| C8 C | ≈A8 A |
| C9 C | ≈A9 A |
| C10 C | ≈A10 A |
A to C conversion table
| A | C |
|---|---|
| A0 A | ≈C0 C |
| A1 A | ≈C1 C |
| A2 A | ≈C2 C |
| A3 A | ≈C3 C |
| A4 A | ≈C4 C |
| A5 A | ≈C5 C |
| A6 A | ≈C6 C |
| A7 A | ≈C7 C |
| A8 A | ≈C8 C |
| A9 A | ≈C9 C |
| A10 A | ≈C10 C |
Quick answers
Quick answers
- How many A is C1 C?
- C1 C is ≈A1 A.
- How many A is C10 C?
- C10 C is ≈A10 A.
- How many A is C3 C?
- C3 C is ≈A3 A.
The units
About these units
C series (envelopes) (C)
Envelope sizes: C4 holds A4 flat.
A series (A)
ISO A sizes: A0 is 1 m², A4 a sixteenth.
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