Celsius to Fahrenheit
Convert celsius (°C) to fahrenheit (°F) instantly. Convert oven, body and outdoor temperatures.
Celsius → Fahrenheit
33.8
°F
1 °C = 33.8 °F
Frequently asked questions
Multiply by 9/5 (or 1.8) and then add 32. The multiplication accounts for the different degree size — 100 Celsius degrees span the same range as 180 Fahrenheit degrees — and the addition accounts for the different zero, since water freezes at 0°C and 32°F. Omitting the +32 is the classic error.
Double it and add 30. For 20°C that gives 70°F against an exact 68. The approximation drifts upward at higher temperatures, overstating by about 1°F for every 2.5°C above 10, but for ordinary weather it is accurate enough to be useful.
The common American settings convert as: 325°F is 163°C, 350°F is 177°C, 375°F is 191°C and 400°F is 204°C. Indian ovens marked in Celsius are usually set to 175 or 180 for the ubiquitous 350°F. Note that oven thermostats are often several degrees out regardless, so an oven thermometer is worth more than precise conversion.
Multiply by 1.8, then add 32
Converting Celsius to Fahrenheit needs two operations rather than one, because the two scales differ in both where zero sits and how large a degree is.
°F = (°C × 9/5) + 32
The 9/5 (or 1.8) accounts for the different degree size: there are 100 Celsius degrees between the freezing and boiling points of water and 180 Fahrenheit degrees across the same span, so each Celsius degree is 1.8 Fahrenheit degrees. The +32 accounts for the different zero: water freezes at 0°C and at 32°F.
Forgetting the +32 is the classic error. It produces an answer that is right about the *size* of a temperature change and wrong about the temperature.
The reference points
- −40°C = −40°F — the one point where the scales coincide
- 0°C = 32°F — water freezes
- 10°C = 50°F
- 20°C = 68°F — comfortable room temperature
- 25°C = 77°F
- 30°C = 86°F
- 37°C = 98.6°F — normal body temperature
- 40°C = 104°F — a serious fever, and an ordinary Indian summer day
- 45°C = 113°F
- 100°C = 212°F — water boils
A mental approximation
Double it and add 30. For 20°C: 40 + 30 = 70°F against an exact 68. For 35°C: 70 + 30 = 100°F against an exact 95 — the approximation drifts at higher temperatures, overstating by about 1°F for every 2.5°C above 10.
For weather in the range most people care about, it is accurate enough to be useful.
Where Indian readers meet Fahrenheit
American recipes and ovens. This is the most common case, and the numbers matter:
- 150°C = 302°F
- 160°C = 320°F
- 180°C = 356°F — the standard baking temperature
- 200°C = 392°F
- 220°C = 428°F
American recipes typically round to convenient Fahrenheit figures — 350°F, which is 177°C, is the ubiquitous one, and Indian ovens marked in Celsius are usually set to 175 or 180 for it.
Medical content. American sources give body temperature in Fahrenheit, and Indian clinical thermometers now mostly read Celsius. Normal is 37°C or 98.6°F; fever is generally taken as above 38°C or 100.4°F.
American weather reporting, which remains Fahrenheit-only.
Temperature difference versus temperature
An important distinction. To convert a temperature, use the full formula. To convert a difference or a change, use only the 1.8 factor — a rise of 5°C is a rise of 9°F, not 41°F.
This catches people when converting things like "the temperature rose by 10 degrees" or a thermostat differential. Adding 32 to a difference is meaningless.