The body as the first ruler
Before standard metres, the classical Vastu tradition measured with the human body: the angula, a finger's breadth, and the hasta, the forearm's length, reckoned as twenty-four angulas. Dimensions in the old manuals — door widths, room spans, the distances at which an obstruction matters — are stated in these units. To apply such rules to a modern plan, you must translate between the two worlds of measure, and that is this tool's whole job.
What the converter does
Enter a length in feet, inches or metres and the tool returns it in hastas and angulas; enter hastas and angulas and it returns the modern equivalents. It keeps the arithmetic exact and shows the working, so a rule phrased as "within eight hastas" becomes a distance you can pace out on site. The conversion follows the practice's adopted equivalence; where regional schools differ on the exact span, the tool states the convention it uses rather than blending them.
How to use this tool
Keep it open beside any rule stated in traditional units. Measure the real distance with a tape, convert, and compare. Working the other way, convert a prescribed hasta dimension into centimetres before giving it to a carpenter or mason, and note the converted figure on the drawing itself.
FAQ
Q. How many angulas in a hasta? Twenty-four, in the convention this practice follows.
Q. Is the hasta the same everywhere? Historical schools varied slightly; the tool declares its convention so your results stay consistent.
Q. Why not just use feet? You can — but the old rules are phrased in hastas, and converting faithfully is what keeps them meaningful.
This page explains the traditional principle; it names no specific text.