yConverter

Convert Japanese tatami (帖) measurements across 9 regional standards — Kyo-ma, Edo-ma, Danchi and more — to m² and ft² with mathematically exact constants.

Japanese rooms are measured in tatami mats (帖) — but not all tatami are the same size. yConverter converts between 9 regional standards with unrounded Shakkan-hō constants, so architects, real estate buyers, and Japan enthusiasts get exact results.

Features:

• 9 regional standards
  • Kyo-ma (京間)
  • Chukyo-ma (中京間)
  • Edo-ma (江戸間)
  • Rokuichi-ma (六一間)
  • Ryūkyū-tatami (琉球畳, 3 variants)
  • Danchi-ma (団地間, 2 variants)
• Mathematically exact conversions using unrounded Shakkan-hō constants
• Formula input — type expressions like directly into any field
• Bidirectional real-time conversion — update any field and all others recalculate instantly
• Live formula preview while typing
• Educational content explaining the mathematics behind each regional standard
• Dark mode support