Celsius to Fahrenheit — °C to °F

To convert celsius to fahrenheit, multiply by 1.8 (9/5) and add 32. The relation is exact: water freezes at 0 °C = 32 °F and boils at 100 °C = 212 °F at standard pressure, so 25 °C = 77 °F.

How to use the celsius to fahrenheit converter

1. Enter the temperature in °C, for example 30.
2. Read the celsius to fahrenheit converter result: 30 × 1.8 + 32 = 86 °F.
3. For negative values keep the sign: −10 × 1.8 + 32 = 14 °F.

What is the Celsius to Fahrenheit formula?

°F = °C × 9/5 + 32 (or °C × 1.8 + 32)

The Celsius–Fahrenheit relationship is exact: a Fahrenheit degree is 5/9 of a Celsius degree and water freezes at 0 °C = 32 °F.

What are Celsius and Fahrenheit?

Temperature measures how hot or cold something is. Celsius and Fahrenheit are everyday scales, kelvin is the SI base unit used in science (0 K is absolute zero), and Rankine is an absolute scale using Fahrenheit-sized degrees.

Celsius to fahrenheit worked examples

• Normal body temperature: 37 × 1.8 + 32 = 98.6 °F
• A mild room temperature: 20 × 1.8 + 32 = 68 °F
• A moderate oven setting: 180 × 1.8 + 32 = 356 °F

Conversion chart

°C	°F	°C	°F
−40	−40	15	59
−30	−22	20	68
−20	−4	25	77
−10	14	30	86
−5	23	35	95
0	32	37	98.6
5	41	40	104
10	50	100	212

Values are rounded to one decimal place.

Quick mental conversion

Double the Celsius and add 30 for a rough estimate: 20 °C → 70 °F (exact 68 °F). It drifts at high temperatures.

Common temperatures

Description	°C	°F
Celsius and Fahrenheit are equal	−40	−40
Water freezes (at sea level)	0	32
Cool room	18	64.4
Comfortable room	21	69.8
Normal body temperature (typical)	37	98.6
Fever threshold often used	38	100.4
Water boils (at sea level)	100	212

Oven temperatures

Gas mark	°C (conventional)	°F
2	150	302 (often written 300)
4	180	356 (often written 350)
5	190	374 (often written 375)
6	200	392 (often written 400)
7	220	428 (often written 425)

Recipes round oven temperatures, so 180 °C and 350 °F are treated as equivalent. For a fan oven, recipes often reduce the Celsius setting by about 20 °C.

Body temperature in Celsius and Fahrenheit

Clinical thermometers in most countries read °C:

°C	°F	Note
36.1	97
37	98.6	traditional normal
37.5	99.5
38	100.4	common fever threshold
39	102.2
40	104

Normal body temperature varies by person, time of day and measuring site; 37 °C (98.6 °F) is the traditional reference.

The reverse formula and −40

To go back, subtract 32 and divide by 1.8: °C = (°F − 32) ÷ 1.8. The two scales meet at −40, where −40 °C = −40 °F. A temperature change converts without the 32: a rise of 10 °C is a rise of 18 °F. For differences, use the temperature interval converter; for the reverse, the fahrenheit to celsius converter.

Fridge, freezer and kitchen settings

Food safety guidance often comes in both scales. A fridge at 4 °C is 39.2 °F, just under the US FDA advice to keep it at or below 40 °F. A freezer at −18 °C is −0.4 °F, the metric match for the familiar 0 °F target.

Cooking temperatures show the same pattern. Sous-vide steak at 57 °C is 134.6 °F. Candy at the soft-ball stage, 112 to 116 °C, is about 234 to 241 °F. A thermometer that only reads one scale is fine as long as you convert the recipe first.

Differences are not temperatures

A change of 10 °C is a change of 18 °F, not 50 °F. When converting a temperature rise or a tolerance, multiply by 1.8 and skip the +32. A celsius to fahrenheit converter for single readings always adds the offset, so use it for temperatures, not for differences. A weather report saying it will be 5 °C warmer tomorrow means 9 °F warmer.

Wine storage is another everyday case. Cellars are kept around 12 to 13 °C, which is about 54 to 55 °F. Serving temperatures for white wine, around 8 to 10 °C, work out to 46 to 50 °F. A celsius to fahrenheit conversion for these small ranges is easy to do in your head with the double-and-add-30 shortcut, which is close enough for a cellar but not for candy making, where a few degrees change the result.

Related converters and calculators

Related conversions:

• Fahrenheit to celsius: °F to °C
• Temperature converter: °C, °F, K
• Temperature difference converter: ΔC and ΔF
• kg to lbs: kg to lb
• cm to inches: cm to in

Sources

NIST Special Publication 811, Appendix B; NIST: SI units – temperature.

Questions about this calculator