Celsius to Fahrenheit: Formula, Quick Tricks & Temperature Table

Temperature conversion between Celsius and Fahrenheit is something you encounter daily — checking weather forecasts from other countries, following recipes, understanding fever readings, or adjusting thermostats. Here are the exact formulas, mental shortcuts, and a reference table covering the temperatures you’ll need most.

The Conversion Formulas

Celsius to Fahrenheit:

°F = (°C × 9/5) + 32
°F = (°C × 1.8) + 32

Fahrenheit to Celsius:

°C = (°F - 32) × 5/9
°C = (°F - 32) / 1.8

Examples:

• 0°C = (0 × 1.8) + 32 = 32°F (freezing point)
• 100°C = (100 × 1.8) + 32 = 212°F (boiling point)
• 72°F = (72 - 32) / 1.8 = 22.2°C (room temperature)
• 98.6°F = (98.6 - 32) / 1.8 = 37°C (body temperature)

Mental Math Tricks

Quick C→F method: Double the Celsius, subtract 10%, add 32.

• 25°C: double = 50, minus 10% (5) = 45, plus 32 = 77°F (actual: 77°F ✓)
• 15°C: double = 30, minus 10% (3) = 27, plus 32 = 59°F (actual: 59°F ✓)

Quick F→C method: Subtract 30, then divide by 2.

• 80°F: 80 - 30 = 50, ÷ 2 = 25°C (actual: 26.7°C — close enough for weather)
• 50°F: 50 - 30 = 20, ÷ 2 = 10°C (actual: 10°C ✓)

Memorize the anchors: These exact conversions serve as reference points:

• -40° = -40° (the scales intersect here)
• 0°C = 32°F
• 10°C = 50°F
• 20°C = 68°F
• 30°C = 86°F
• 37°C = 98.6°F
• 100°C = 212°F

Each 10°C increment equals 18°F. Knowing this, you can quickly estimate any temperature from the nearest anchor point.

Common Temperature References

Weather:

Description	Celsius	Fahrenheit
Extreme cold	-30°C	-22°F
Very cold	-10°C	14°F
Freezing	0°C	32°F
Cool/Chilly	10°C	50°F
Comfortable	20–22°C	68–72°F
Warm	28–30°C	82–86°F
Hot	35°C	95°F
Extreme heat	40°C+	104°F+

Body and Medical:

Condition	Celsius	Fahrenheit
Hypothermia	<35°C	<95°F
Normal body temp	36.5–37.5°C	97.7–99.5°F
Low-grade fever	37.5–38.3°C	99.5–100.9°F
Fever	38.3–40°C	100.9–104°F
High fever	>40°C	>104°F

Cooking:

Setting/Use	Celsius	Fahrenheit
Low oven	150°C	300°F
Moderate oven	180°C	350°F
Hot oven	200°C	400°F
Very hot oven	230°C	450°F
Broil/Grill	260°C	500°F
Deep frying	175–190°C	350–375°F
Candy/caramel	160°C	320°F
Water simmers	85–95°C	185–203°F

Kelvin: The Scientific Scale

Kelvin uses the same increment size as Celsius but starts at absolute zero (-273.15°C):

K = °C + 273.15
°C = K - 273.15

Key Kelvin values:

• 0 K = -273.15°C = Absolute zero (no molecular motion)
• 273.15 K = 0°C = Water freezes
• 373.15 K = 100°C = Water boils
• 5778 K = Surface of the Sun

Kelvin is used in science, color temperature (photography and lighting), and engineering. You’ll rarely need it in everyday life, but it appears in light bulb ratings (2700K warm white, 5000K daylight) and astrophysics discussions.

Calculate instantly with our Celsius to Fahrenheit Converter.