🌡️ OAT Converter
Outside air temperature C to F and ISA deviation
About this calculator
The OAT Converter switches outside air temperature between Celsius and Fahrenheit. Aviation performance charts, density altitude math, and METARs use Celsius, while many pilots think in Fahrenheit; enter either and get both. The formula is the familiar 9/5 plus 32.
Tip: memorize a few key anchors — 15°C is 59°F (standard sea level), 0°C is 32°F, and minus 40 is the same in both — so you can sanity-check the calculator without reaching for it on a cold ramp.