Span to Centimeter Converter

How it is calculated

This is a fixed-ratio conversion with 1 span = 22.86 cm, which is exactly 9 inches (9 × 2.54 cm). The direction setting decides which way it runs:

Span to cm: cm = spans × 22.86
Cm to span: spans = cm ÷ 22.86

Results are shown to four decimals, together with the ratio and a line repeating both values. If the direction is missing or unrecognised, the tool assumes span to cm. Zero converts to zero, but a negative value shows no result because a length cannot be below zero. The span used here is the 9-inch span; spans in other traditions or regions were not always the same length, so check which one your source means. Decimals must be typed with a point; a decimal comma such as 3,5 gives no result.

Common mistakes

• Leaving the direction on the wrong setting. Entering 80 with span to cm selected gives 1,828.8000 cm, not 3.4996 spans.
• Mixing up the span with the hand-width unit "palm" or the "hand" used for horses. Only the 9-inch span of 22.86 cm is used here.
• Assuming an old source used the same span. Historical spans varied between regions and eras, so 22.86 cm is a modern standard, not a guarantee for every text.
• Typing a decimal comma such as 3,5. The tool wants a point (3.5); with a comma it gives no result.
• Entering a negative length, for instance an offset or difference. The tool rejects it and shows nothing; convert the size as a positive number and apply the sign yourself.