How to use this calculator
Enter your values in the fields above and click Calculate to see your results instantly. All calculations run in your browser — no data is sent to a server and results appear immediately. Click Clear to reset all fields and start over.
Understanding your inputs
Each input field is labeled with the specific value it expects. Hover over the ? hint icons (where present) for additional guidance on what each field means and what units to use. For best results, double-check that all your input values use consistent units before calculating.
Interpreting the results
Results are shown immediately after clicking Calculate. The highlighted result card shows the primary output — the value most people need. Additional cards show supporting calculations that provide context and help you verify the primary result makes sense. If results seem unexpected, re-check your inputs for typos or unit mismatches.
About this unit conversion calculator
This calculator implements standard unit conversion formulas used by professionals and students alike. The underlying math has been verified against reference implementations and textbook examples. For critical applications, always cross-reference results with authoritative sources or a qualified professional.
Temperature Conversion Chart: Common Reference Values
Use this Celsius to Fahrenheit chart for quick lookups — from everyday weather and body temperature to cooking and scientific reference points.
| °C |
°F |
K |
Description |
| −40 | −40 | 233 | °C and °F converge here |
| −20 | −4 | 253 | Cold winter |
| −10 | 14 | 263 | Freezing cold |
| 0 | 32 | 273 | Water freezes |
| 10 | 50 | 283 | Cool |
| 20 | 68 | 293 | Room temperature |
| 21 | 69.8 | 294 | Standard room temperature |
| 25 | 77 | 298 | Warm room |
| 30 | 86 | 303 | Hot day |
| 37 | 98.6 | 310 | Human body temperature |
| 40 | 104 | 313 | Fever |
| 100 | 212 | 373 | Water boils |
| 180 | 356 | 453 | Baking (low) |
| 200 | 392 | 473 | Baking (medium) |
| 220 | 428 | 493 | Baking (high) |
How to Convert Celsius to Fahrenheit (and Back)
Temperature conversions use both a scaling factor and an offset — unlike length or weight conversions which only scale. The three formulas you need:
- °F = (°C × 9/5) + 32 — Celsius to Fahrenheit
- °C = (°F − 32) × 5/9 — Fahrenheit to Celsius
- K = °C + 273.15 — Celsius to Kelvin
Worked Examples
- Body temperature: 37°C → (37 × 9/5) + 32 = 66.6 + 32 = 98.6°F
- Oven temperature: 180°C → (180 × 9/5) + 32 = 324 + 32 = 356°F
- Freezing point: 0°C → (0 × 9/5) + 32 = 0 + 32 = 32°F
A useful mental shortcut: double the Celsius temperature and add 30 to get an approximate Fahrenheit value. For example, 20°C × 2 + 30 = 70°F (actual: 68°F) — close enough for everyday estimates.
Body Temperature: What's Normal in Celsius and Fahrenheit?
The commonly cited normal body temperature is 37°C (98.6°F), but individual readings vary throughout the day and between people. The healthy range is 36.1–37.2°C (97–99°F). A reading of 38°C (100.4°F) or higher is generally classified as a fever in adults.
Axillary (armpit) readings run about 0.3–0.6°C lower than oral readings. Rectal and ear-canal readings tend to run 0.3–0.5°C higher. When comparing temperatures, always note the measurement site for accurate interpretation.
Frequently Asked Questions
How precise are these conversions?
These conversions use standard international definitions and are precise to the limits of floating-point arithmetic (typically 15 significant figures). For most practical purposes (engineering, cooking, everyday use) this precision far exceeds what's needed. Scientific calculations requiring extreme precision should use specialized software with arbitrary precision arithmetic.
Why do some conversion factors look odd?
Many conversion factors between imperial and metric units are defined by exact treaty definitions (e.g., 1 inch = exactly 25.4 mm since 1959). Others are derived quantities with irrational decimal expansions. The seemingly odd numbers reflect historical accident — the systems were developed independently and unit relationships weren't designed to be round numbers.
What is the difference between mass and weight?
Mass is a measure of how much matter an object contains (kilograms, grams, pounds-mass) and doesn't change with gravity. Weight is a force equal to mass × gravitational acceleration (newtons, pounds-force). In everyday use on Earth's surface the distinction rarely matters, but it becomes critical in engineering, aerospace, and scientific contexts.
How do I convert temperatures correctly?
Temperature conversions require both scaling and shifting, unlike most unit conversions. Fahrenheit to Celsius: subtract 32, multiply by 5/9. Celsius to Kelvin: add 273.15. Kelvin is the SI base unit — always positive and starts at absolute zero. For temperature differences (not absolute temperatures), you only need the scaling factor: 1°C change = 1.8°F change.
What is 37 degrees Celsius in Fahrenheit?
37°C equals 98.6°F — normal human body temperature. Calculation: (37 × 9/5) + 32 = 66.6 + 32 = 98.6°F. A temperature of 37°C is healthy; 38°C (100.4°F) or above is considered a fever.
What is 100 degrees Fahrenheit in Celsius?
100°F equals approximately 37.78°C. Calculation: (100 − 32) × 5/9 = 68 × 5/9 ≈ 37.78°C. This is just above normal body temperature (37°C / 98.6°F), which is why 100°F can signal an early-stage fever.
How do you convert Celsius to Fahrenheit?
Multiply the Celsius value by 9/5 (or 1.8), then add 32. Formula: °F = (°C × 9/5) + 32. Example: 25°C → 25 × 1.8 + 32 = 45 + 32 = 77°F. For a quick mental estimate, double the Celsius value and add 30 (e.g., 20°C → 40 + 30 = 70°F, actual is 68°F).
What temperature is 180°C in Fahrenheit?
180°C equals 356°F. This is a common low–moderate baking temperature used for slow roasting and gentle baking. Calculation: (180 × 9/5) + 32 = 324 + 32 = 356°F.
What is normal body temperature in Celsius?
Normal body temperature is typically cited as 37°C (98.6°F). The healthy range is approximately 36.1–37.2°C (97–99°F). A reading of 38°C (100.4°F) or higher is generally considered a fever in adults. Readings can vary by time of day, measurement site, age, and physical activity.
What is absolute zero in Celsius and Fahrenheit?
Absolute zero is −273.15°C and −459.67°F, equivalent to 0 Kelvin. It is the lowest theoretically possible temperature — the point at which atoms and molecules have minimum thermal energy. No physical object can be cooled below absolute zero.