-40 Fahrenheit to Celsius (°F to °C) – Instant & Accurate
Last updated: February 28, 2026
-40 °F = -40.00 °C
Using the formula °C = (°F − 32) × 5⁄9: (-40 − 32) × 5⁄9 = -40.00 °C
How to convert from Fahrenheit to Celsius
It is easy to convert a temperature value from Fahrenheit to Celsius by using the formula below:
[°C] = ([°F] − 32) × 5⁄9
or
Value in Celsius = (Value in Fahrenheit - 32) × 5⁄9
To change -40° Fahrenheit to Celsius, just need to replace the value [°F] in the formula below and then do the math.
Step-by-step Solution:
Write down the formula: [°C] = ([°F] − 32) × 5⁄9
Plug the value in the formula: (-40 - 32) × 5⁄9
Subtract 32: (-72) × 5⁄9
Multiply by 5: (-360) / 9
Divide by 9: -40.00 (answer)
Nearby Conversions
Fahrenheit to Celsius Conversion Table (32–212 °F)
| Fahrenheit | Celsius | Fahrenheit | Celsius |
|---|---|---|---|
| 32 | 0.0 | 34 | 1.1 |
| 36 | 2.2 | 38 | 3.3 |
| 40 | 4.4 | 42 | 5.6 |
| 44 | 6.7 | 46 | 7.8 |
| 48 | 8.9 | 50 | 10.0 |
| 52 | 11.1 | 54 | 12.2 |
| 56 | 13.3 | 58 | 14.4 |
| 60 | 15.6 | 62 | 16.7 |
| 64 | 17.8 | 66 | 18.9 |
| 68 | 20.0 | 70 | 21.1 |
| 72 | 22.2 | 74 | 23.3 |
| 76 | 24.4 | 78 | 25.6 |
| 80 | 26.7 | 82 | 27.8 |
| 84 | 28.9 | 86 | 30.0 |
| 88 | 31.1 | 90 | 32.2 |
| 92 | 33.3 | 94 | 34.4 |
| 96 | 35.6 | 98 | 36.7 |
| 100 | 37.8 | 102 | 38.9 |
| 104 | 40.0 | 106 | 41.1 |
| 108 | 42.2 | 110 | 43.3 |
| 112 | 44.4 | 114 | 45.6 |
| 116 | 46.7 | 118 | 47.8 |
| 120 | 48.9 | 122 | 50.0 |
| 124 | 51.1 | 126 | 52.2 |
| 128 | 53.3 | 130 | 54.4 |
| 132 | 55.6 | 134 | 56.7 |
| 136 | 57.8 | 138 | 58.9 |
| 140 | 60.0 | 142 | 61.1 |
| 144 | 62.2 | 146 | 63.3 |
| 148 | 64.4 | 150 | 65.6 |
| 152 | 66.7 | 154 | 67.8 |
| 156 | 68.9 | 158 | 70.0 |
| 160 | 71.1 | 162 | 72.2 |
| 164 | 73.3 | 166 | 74.4 |
| 168 | 75.6 | 170 | 76.7 |
| 172 | 77.8 | 174 | 78.9 |
| 176 | 80.0 | 178 | 81.1 |
| 180 | 82.2 | 182 | 83.3 |
| 184 | 84.4 | 186 | 85.6 |
| 188 | 86.7 | 190 | 87.8 |
| 192 | 88.9 | 194 | 90.0 |
| 196 | 91.1 | 198 | 92.2 |
| 200 | 93.3 | 202 | 94.4 |
| 204 | 95.6 | 206 | 96.7 |
| 208 | 97.8 | 210 | 98.9 |
| 212 | 100.0 | 214 | 101.1 |
Related Temperature Conversions
Temperature Converters
- Celsius to Fahrenheit (°C to °F)
- Fahrenheit to Celsius (°F to °C)
- Celsius to Kelvin (°C to K)
- Kelvin to Celsius (K to °C)
- Fahrenheit to Kelvin (°F to K)
- Kelvin to Fahrenheit (K to °F)
- All Temperature Tools
Popular Fahrenheit to Celsius conversions
More Temperature Conversions
The Intersection of Two Scales
−40 °F is identically −40 °C — the only temperature where both scales agree. This mathematical convergence point is found by solving the conversion formula for equality. In practice, −40 represents extreme cold: it is near the average January temperature in Yakutsk, Russia, and is the minimum operational temperature specified in many military equipment standards (MIL-STD-810). At this temperature, mercury thermometers cease to function (mercury freezes at −38.83 °C), requiring alcohol or electronic sensors.
Learn why this is the only point where both scales meet: Celsius vs Fahrenheit.
Data Accuracy
Conversions on this page follow the internationally defined temperature scale relationship: °C = (°F − 32) × 5/9. All arithmetic is carried out in double-precision floating point (IEEE 754) before rounding the displayed result to one decimal place. Values are consistent with the ITS-90 framework maintained by the International Bureau of Weights and Measures (BIPM).
About This Page
Content maintained by the CelsiusFahrenheit.co editorial team. All conversions follow the International Temperature Scale of 1990 (ITS-90) as defined by the Bureau International des Poids et Mesures (BIPM). Calculations use IEEE 754 double-precision arithmetic. Last reviewed: February 2026.