Weather forecast, thermostat or recipe in Fahrenheit and need Celsius — or a Celsius reading you want in °F? Pick the direction, then type the temperature or tap a common one (use the ± button for below zero). You get the answer to one decimal, the whole-degree figure a weather app would show, Kelvin, and the quick mental shortcut with how far off it is. Outdoor readings get a rough feel (cold, mild, hot), and readings near 100 °F get a check against the common fever cutoff. Converting a change, like “10 degrees warmer”? Switch to A temp change — it skips the 32. The chart below highlights the row you’re on.
How it works: °C = (°F − 32) × 5 ⁄ 9 and °F = °C × 9 ⁄ 5 + 32; kelvins = °C + 273.15. A temperature change skips the 32 — a 10 °F rise is 10 × 5 ⁄ 9 ≈ 5.6 °C — and the mental shortcuts are exact only at 50 °F (10 °C), drifting further off the further you go. 98.6 °F (37 °C) is the traditional average body temperature and 100.4 °F (38 °C) a widely used fever cutoff, but normal varies by person, time of day and where it’s measured, so treat these as reference points, not medical advice. Water boils at 212 °F (100 °C) at sea level, a little lower at altitude.