Celsius to Fahrenheit Chart: Common Temperatures 2026

How Celsius to Fahrenheit is worked out

Celsius and Fahrenheit are two ways of measuring the same temperature, and the formula between them is exact: °F = °C × 9/5 + 32. Multiply the Celsius temperature by 9, divide by 5, and add 32. The reverse is °C = (°F − 32) × 5/9: subtract 32 from the Fahrenheit temperature, multiply by 5, and divide by 9. The chart lists the nine temperatures people look up most, from -40 °C to 100 °C, with the exact Fahrenheit value for each, and the lookup converts any Celsius value you enter and shows the nearest table row.

At the default — 20 °C — the Fahrenheit is 20 × 9/5 + 32 = 68 °F, and the nearest table row is 20 °C → 68 °F, room temperature. The reverse of 68 °F is 20 °C, the reverse of 32 °F is 0 °C, the reverse of 212 °F is 100 °C, the reverse of 98.6 °F is 37 °C, the reverse of -40 °F is -40 °C, and the reverse of 77 °F is 25 °C.

This is a Celsius-to-Fahrenheit chart, and it is not a Kelvin chart: Kelvin is a third scale, and a Kelvin temperature is the Celsius temperature plus 273.15, so 20 °C is 293.15 K. Nothing here is in Kelvin, and no row in the chart is a Kelvin value. Body temperature is 37 °C, which is 98.6 °F: that is the standard figure, and a real body runs a little above or below it through the day.

The worked example, line by line

Setup: 20 °C.

Line 1 — multiply by 9/5. 20 × 9 ÷ 5 = 36.

Line 2 — add 32. 36 + 32 = 68 °F.

Line 3 — the nearest row. 20 °C is a row in the chart itself: 20 °C → 68 °F, room temperature.

Line 4 — the reverse. (68 − 32) × 5/9 = 36 × 5 ÷ 9 = 20 °C.

Every branch, checked

0 °C: 0 × 9/5 + 32 = 32 °F — water freezes. This is the freezing point on both scales, and it is the row most people look up first.

37 °C: 37 × 9/5 + 32 = 66.6 + 32 = 98.6 °F — body temperature. This is the one row with a decimal: 37 × 9/5 is 66.6, not a whole number.

100 °C: 100 × 9/5 + 32 = 180 + 32 = 212 °F — water boils. This is the boiling point at sea level, and it is the top row of the chart.

-40 °C: -40 × 9/5 + 32 = -72 + 32 = -40 °F — the crossover point. This is the only temperature where Celsius and Fahrenheit agree, and it is the same in both directions: -40 °F is -40 °C.

25 °C: 25 × 9/5 + 32 = 45 + 32 = 77 °F — a warm day. This is the row for a warm summer afternoon.

-20 °C: -20 × 9/5 + 32 = -36 + 32 = -4 °F — a cold winter day. Below zero, the Fahrenheit stays negative until the Celsius passes -17.78 °C.

Extra — 15 °C: 15 × 9/5 + 32 = 27 + 32 = 59 °F. This is not a row in the chart: it sits between the 10 °C row (50 °F) and the 20 °C row (68 °F), and the nearest row is 10 °C at 5 °C away, against 20 °C at 5 °C away — a tie, settled to the lower row.

Reverse — Fahrenheit to Celsius: 68 °F is 20 °C, 32 °F is 0 °C, 212 °F is 100 °C, 98.6 °F is 37 °C, -40 °F is -40 °C, and 77 °F is 25 °C. The reverse formula is °C = (°F − 32) × 5/9.

What the defaults assume

The model assumes the standard formula, °F = °C × 9/5 + 32, which is exact: there is no rounding in the formula itself, and the Fahrenheit is shown to 1 decimal place, so 37 °C shows as 98.6 °F and every whole-number result shows without a decimal. The nearest row is the table row closest in Celsius, settled to the lower row on a tie. Body temperature is taken as 37 °C, which is 98.6 °F, and water is taken to freeze at 0 °C and boil at 100 °C at sea level. This is not a Kelvin chart: Kelvin is Celsius plus 273.15, and no row here is a Kelvin value. Rounding convention: Fahrenheit to 1 decimal place, Celsius as entered, and all figures are computed from unrounded values, rounded only for display.

Output · formula · meaning

Who uses this

• The cook following an American recipe: they learn 20 °C is 68 °F, and an oven at 180 °C is 356 °F — so they know the room temperature row by heart, and they check the chart before they set the oven.
• The traveller checking the weather abroad: they learn 25 °C is 77 °F, a warm day, and 0 °C is 32 °F, freezing — so they know whether to pack a jacket, and they check the reverse when the forecast is in Fahrenheit.
• The parent taking a temperature: they learn 37 °C is 98.6 °F, body temperature — so they know a reading of 100.4 °F is 38 °C, and they check the chart instead of guessing.
• The student learning the two scales: they learn -40 °C is -40 °F, the crossover point — so they know the two scales meet at exactly one temperature, and they check the formula °F = °C × 9/5 + 32.

Accuracy & limitations

The math is exact for the numbers you enter: the Fahrenheit is the Celsius times 9/5 plus 32, and the reverse is the Fahrenheit minus 32 times 5/9. What the model cannot do is measure your temperature for you: check the thermometer, and check whether it reads in Celsius or Fahrenheit before you convert. Body temperature is taken as 37 °C, which is 98.6 °F, and a real body runs a little above or below it through the day. Water is taken to freeze at 0 °C and boil at 100 °C at sea level, and the boiling point falls as the altitude rises. This is not a Kelvin chart: Kelvin is Celsius plus 273.15, and no row here is a Kelvin value. For oven temperatures, see oven temperature chart; for grill temperatures, see grill temperature chart.