Why is 0°C not 0°F?

They use different zero-points. 0°C is water freezing; 0°F was originally a freezing mixture of brine (salt water), which is colder than plain water. The two scales also have different-sized degrees, which is why the conversion involves multiplication, not just addition.

What temperatures should I memorize for cooking and travel?

Cooking: 350°F = 175°C (most baking), 400°F = 200°C (roasting), 450°F = 230°C (high heat / pizza), 425°F = 220°C (chicken). Travel weather: 0°C = 32°F (freezing), 10°C = 50°F (cool), 20°C = 68°F (mild), 25°C = 77°F (warm), 30°C = 86°F (hot), 35°C = 95°F (uncomfortably hot). Body: normal body temp 37°C = 98.6°F, fever starts ~38°C = 100.4°F. These cover 95% of practical conversion needs.

Is there a quick mental conversion shortcut?

Roughly: double Celsius and add 30 to estimate Fahrenheit. 20°C → 40+30 = 70°F (actual: 68°F). 30°C → 60+30 = 90°F (actual: 86°F). For Fahrenheit to Celsius, subtract 30 then halve: 75°F → 45/2 = 22.5°C (actual: 23.9°C). Accuracy is within 5°F across normal weather ranges. For exact conversions, use the formula or this tool.

When do scientists use Kelvin vs. Celsius?

Kelvin in physics, chemistry, astronomy, thermodynamics — anywhere ratios or absolute temperatures matter. 200K vs. 400K is meaningfully 'twice as hot' in molecular kinetic energy; 100°C vs. 200°C is not (those are 373K and 473K, only a 27% difference). Celsius for chemistry lab temperatures, biology, weather, and medicine — anywhere you're working with a relative scale around water's freezing/boiling. Conversion: K = °C + 273.15 (a simple offset).

What temperatures are dangerous to humans?

Body core: hypothermia below 35°C (95°F), heat exhaustion above 40°C (104°F), heat stroke at 41°C (106°F), critical above 42°C (107.6°F). Air temperature: hypothermia risk below 0°C (32°F) with wind, heat stroke risk above 35°C (95°F) with humidity. Cooking: kill bacteria at 75°C (165°F) for poultry, 63°C (145°F) for whole-cut beef/pork, 54°C (130°F) for medium-rare beef. Surface burns: pain threshold ~45°C (113°F), instant burn at 60°C (140°F), boiling water 100°C (212°F).

Why does my oven thermometer disagree with the dial setting?

Most home ovens are 15-50°F off the displayed temperature. Causes: aging heating elements, calibration drift, location of the dial sensor (often in the back of the oven, where the temperature differs from the center where food cooks). Use a separate oven thermometer ($10-15) to check; for serious baking, calibrate. Recipes assume 'true' temperature so a dial set to 350°F that actually runs at 325°F will yield underbaked results. Convection ovens add another wrinkle: they typically run 25°F hotter than the conventional setting due to fan-driven heat circulation.

Unit Converters · Free tool

Temperature Converter

Convert between Celsius, Fahrenheit, and Kelvin instantly. Live conversion as you type.

Updated June 2026

Celsius

20°C

Fahrenheit

68°F

Kelvin

293.15 K

Formulas: °F = °C × 9/5 + 32 · K = °C + 273.15

Freezing water: 0°C = 32°F = 273.15 K. Body temp: 37°C = 98.6°F.

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What it does

A simple Celsius, Fahrenheit, and Kelvin converter for cooking, science, and travel. Type in any field and the other two update live. Formulas are shown below so you know exactly how the conversion is happening.

Temperature conversion catches most people at the wrong moment — in the kitchen with a recipe in the “wrong” units, or checking foreign weather before a trip. 0°C = 32°F (freezing), 100°C = 212°F (boiling), 20°C = 68°F (comfortable room temperature).

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Example input & output

Input

Celsius: 180°C

Output

Fahrenheit: 356°F
Kelvin: 453.15 K

180°C is a common oven setting for baking — roughly 'moderate' heat.

How to use it

Type a value in any of the three boxes — Celsius, Fahrenheit, or Kelvin.
The other two update live.
Scan the formula below if you want to do the math by hand.
Clear the field when you're ready for a new value.

How it works

Three straightforward formulas: °F = °C × 9/5 + 32, °C = (°F − 32) × 5/9, and K = °C + 273.15. Kelvin is the SI unit (absolute zero is 0 K = −273.15°C); Celsius and Fahrenheit are both relative scales whose zero-points were chosen historically, not physically.

When to use this tool

Quick single conversions in the kitchen, lab, or travel context.
Double-checking a mental conversion before acting on it.

When not to use it

Converting a whole recipe — convert each temperature and amount individually with the right tool.
Wind chill, heat index, or humidity-adjusted temperature (those have their own formulas).

Common use cases

Following a recipe written in the 'other' unit.
Checking a foreign weather forecast before travel.
Converting lab or science class readings between units.
Making sure an oven setting matches what a recipe calls for.

Frequently asked questions

Why is 0°C not 0°F?: They use different zero-points. 0°C is water freezing; 0°F was originally a freezing mixture of brine (salt water), which is colder than plain water. The two scales also have different-sized degrees, which is why the conversion involves multiplication, not just addition.
What temperatures should I memorize for cooking and travel?: Cooking: 350°F = 175°C (most baking), 400°F = 200°C (roasting), 450°F = 230°C (high heat / pizza), 425°F = 220°C (chicken). Travel weather: 0°C = 32°F (freezing), 10°C = 50°F (cool), 20°C = 68°F (mild), 25°C = 77°F (warm), 30°C = 86°F (hot), 35°C = 95°F (uncomfortably hot). Body: normal body temp 37°C = 98.6°F, fever starts ~38°C = 100.4°F. These cover 95% of practical conversion needs.
Is there a quick mental conversion shortcut?: Roughly: double Celsius and add 30 to estimate Fahrenheit. 20°C → 40+30 = 70°F (actual: 68°F). 30°C → 60+30 = 90°F (actual: 86°F). For Fahrenheit to Celsius, subtract 30 then halve: 75°F → 45/2 = 22.5°C (actual: 23.9°C). Accuracy is within 5°F across normal weather ranges. For exact conversions, use the formula or this tool.
When do scientists use Kelvin vs. Celsius?: Kelvin in physics, chemistry, astronomy, thermodynamics — anywhere ratios or absolute temperatures matter. 200K vs. 400K is meaningfully 'twice as hot' in molecular kinetic energy; 100°C vs. 200°C is not (those are 373K and 473K, only a 27% difference). Celsius for chemistry lab temperatures, biology, weather, and medicine — anywhere you're working with a relative scale around water's freezing/boiling. Conversion: K = °C + 273.15 (a simple offset).
What temperatures are dangerous to humans?: Body core: hypothermia below 35°C (95°F), heat exhaustion above 40°C (104°F), heat stroke at 41°C (106°F), critical above 42°C (107.6°F). Air temperature: hypothermia risk below 0°C (32°F) with wind, heat stroke risk above 35°C (95°F) with humidity. Cooking: kill bacteria at 75°C (165°F) for poultry, 63°C (145°F) for whole-cut beef/pork, 54°C (130°F) for medium-rare beef. Surface burns: pain threshold ~45°C (113°F), instant burn at 60°C (140°F), boiling water 100°C (212°F).
Why does my oven thermometer disagree with the dial setting?: Most home ovens are 15-50°F off the displayed temperature. Causes: aging heating elements, calibration drift, location of the dial sensor (often in the back of the oven, where the temperature differs from the center where food cooks). Use a separate oven thermometer ($10-15) to check; for serious baking, calibrate. Recipes assume 'true' temperature so a dial set to 350°F that actually runs at 325°F will yield underbaked results. Convection ovens add another wrinkle: they typically run 25°F hotter than the conventional setting due to fan-driven heat circulation.

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