340 degrees Celsius = 644°F (exact). Rounded: 644°F. In Kelvin: 613.15 K. In Rankine: 1103.67°R.
High industrial temperature — used in metalwork, ceramics, and manufacturing.
For context: 0°C = 32°F (freezing), 20°C = 68°F (room temp), 37°C = 98.6°F (body temp), 100°C = 212°F (boiling). The Celsius scale places 0° and 100° at the freezing and boiling points of water at sea level.
All temperature units: 644°F · 613.15 K (Kelvin) · 1103.67°R (Rankine). Kelvin starts at absolute zero (−273.15°C). Rankine is used in some US engineering applications.
Formula: °F = (°C × 9/5) + 32. For 340°C: (340 × 1.8) + 32 = 612 + 32 = 644°F. Reverse: °C = (°F − 32) × 5/9 = (644 − 32) × 0.5556 = 340°C.
340°C = 644°F (exact: 644°F). Formula: (340 × 9/5) + 32 = 644°F.
Multiply by 1.8 then add 32: 340 × 1.8 = 612, + 32 = 644°F. Quick estimate: double the Celsius value and add 30 → 710°F (approximate).
Add 273.15: 340 + 273.15 = 613.15 K. Kelvin is used in science — 0 K is absolute zero (the coldest possible temperature).
High industrial temperature — used in metalwork, ceramics, and manufacturing. In Fahrenheit: 644°F is very hot.