⚡ Instant Conversion ★ 4.9 Rated

Temperature Converter: °C ⇄ °F ⇄ K in Real Time

Type a number, watch the live thermo-dial move. Built for cooking, weather, science, and health — no signup, no ads blocking the tool.

⚡ Short version: °F = °C × 9/5 + 32. °C = (°F − 32) × 5/9. K = °C + 273.15. Water freezes at 0°C / 32°F / 273.15K and boils at 100°C / 212°F / 373.15K.
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20°
CELSIUS

On this page

  1. More than a converter
  2. Features
  3. Reference numbers
  4. Use cases
  5. How to use
  6. Who it's for
  7. FAQ

More than just a temperature converter

Most converters give you a single number and stop there. Toolyfi's version keeps all three scales open at once and syncs them live, so you can see Celsius, Fahrenheit, and Kelvin moving together as you type — the thermo-dial and tube fill in real time to give you an instant visual sense of "how hot is that, really."

Whether you're checking an oven setting from a US recipe, reporting a fever in the unit your doctor expects, or converting lab data for a physics assignment, the goal is the same: get an accurate number in under two seconds without hunting through ads or pop-ups.

Built for speed and accuracy

Live Sync

All three scales update instantly as you type — no "Convert" button needed.

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Two Decimal Precision

Accurate to 0.01°, useful for lab work as well as everyday checks.

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Visual Thermo-Dial

A live gauge and tube fill so you can gauge intensity at a glance.

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One-Tap Copy

Copy all three converted values together for notes, recipes, or reports.

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No Signup

100% free, runs in your browser, nothing is stored on our servers.

Reference numbers worth memorizing

0K
Absolute Zero
37°C
Body Temp
100°C
Water Boils
−40°
C = F (same!)
DescriptionCelsiusFahrenheitKelvin
Absolute Zero−273.15°C−459.67°F0 K
Very Cold Day−18°C0°F255.15 K
Freezing Point of Water0°C32°F273.15 K
Room Temperature21°C70°F294.15 K
Body Temperature37°C98.6°F310.15 K
Fever Threshold38°C100.4°F311.15 K
Hot Bath40°C104°F313.15 K
Water Boils100°C212°F373.15 K
Moderate Oven180°C356°F453.15 K
Hot Oven220°C428°F493.15 K

Common use cases

Cooking with US recipes: Most American recipes list oven temperatures in Fahrenheit while the rest of the world bakes in Celsius. A quick check here prevents a burnt or undercooked dish. Pair it with our unit converter for cups-to-grams conversions in the same recipe.

Travel & weather: If you're checking a forecast from a US site while living in a Celsius country (or vice versa), converting the day's high and low takes the guesswork out of packing.

Health tracking: Thermometers sold in different countries use different scales. Converting a child's or your own reading against the fever threshold above helps you react appropriately without confusion.

Science & engineering: Kelvin is the SI base unit for thermodynamic calculations. Students and engineers often need to shift between lab notation (K) and everyday reporting (°C).

How to use it in 3 steps

1. Pick any field. Click into Celsius, Fahrenheit, or Kelvin — it doesn't matter which.

2. Type your value. The other two fields, the dial, and the tube update instantly.

3. Copy or clear. Use "Copy Results" to grab all three values in one line, or "Clear" to start over.

Who this tool is built for

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Home Cooks

Convert oven temps between US and metric recipes.

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Students

Physics and chemistry homework involving Kelvin conversions.

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Parents & Caregivers

Reading a fever thermometer from another country's scale.

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Travelers

Understanding foreign weather reports at a glance.

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Lab Technicians

Fast, precise unit shifts for experiments and reports.

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Engineers

Cross-checking spec sheets that mix unit systems.

Need more than temperature?

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Frequently asked questions

How do I convert Celsius to Fahrenheit?
Multiply by 9/5 (1.8), then add 32. Example: 20°C × 1.8 = 36, + 32 = 68°F.
How do I convert Fahrenheit to Celsius?
Subtract 32, then multiply by 5/9. Example: 98.6°F − 32 = 66.6, × 5/9 = 37°C.
What is 0 Kelvin in Celsius?
0 K equals −273.15°C, known as absolute zero — the coldest temperature theoretically possible.
Is there a quick mental shortcut?
Double the Celsius value and add 30 for a rough Fahrenheit estimate, accurate within about 5–8°F for everyday temperatures.
Why does Kelvin never go negative?
Kelvin starts at absolute zero, the lowest possible energy state, so there is no value below 0 K in standard physics.
What temperature counts as a fever?
38°C (100.4°F) or higher is generally considered a fever, versus a normal average of 37°C (98.6°F).

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