What is the Celsius to Fahrenheit formula?

°F = (°C × 9/5) + 32. For example, 25°C × 1.8 + 32 = 77°F. The reverse is °C = (°F − 32) × 5/9.

What is normal body temperature in both scales?

37°C equals 98.6°F — the traditional “normal”. A fever threshold of 38°C is 100.4°F, which is the number most medical guidance uses.

Why does −40 convert to itself?

−40 is the unique point where both scales meet: −40°C = −40°F. It happens because the scales have different zero points and slopes, and the lines cross exactly there. It’s also a handy sanity check for any converter.

What’s a quick mental shortcut?

Double the Celsius value and add 30: 20°C → about 70°F (exact: 68°F). It’s within a few degrees for everyday weather (0–35°C) but drifts at extremes — use the exact formula when it matters.

What oven temperatures do common recipes use?

160°C = 320°F, 180°C = 356°F (usually stated as 350°F), 200°C = 392°F (≈400°F), 220°C = 428°F (≈425°F). US recipes round to the nearest 25°F, so don’t worry about single-degree precision when baking.

Is my input stored anywhere?

No — the conversion is a one-line formula running in your browser. Nothing is uploaded, stored or tracked, and the converter keeps working offline once the page has loaded.

Celsius to Fahrenheit Converter

Convert °C to °F and back instantly — with body, weather and oven temperature charts.

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Celsius (°C)

Fahrenheit (°F)

Quick values

How to convert Celsius to Fahrenheit

Type a temperature on either side — conversion happens instantly in both directions using the exact formula °F = °C × 9/5 + 32. Quick buttons cover the values people actually look up: 37°C body temperature (98.6°F), room temperatures, weather extremes, boiling point and the curious −40° crossover where both scales read the same.

Celsius to Fahrenheit reference chart

°C	°F	What it means
−40	−40	Scales intersect
0	32	Water freezes
10	50	Cool day
20	68	Room temperature
25	77	Warm day
30	86	Hot day
37	98.6	Body temperature
38	100.4	Fever threshold
100	212	Water boils
180	356	Baking (“350°F”)

Why the formula works

The scales differ in two ways: where zero sits and how big a degree is. Water freezes at 0°C but 32°F (hence the +32), and a Celsius degree is 1.8× larger than a Fahrenheit degree (hence ×9/5). The popular mental shortcut — double it and add 30 — approximates this well for everyday weather but drifts at the extremes: at 100°C it gives 230°F instead of 212°F. Use the shortcut for conversation and this converter when the number matters.

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Frequently Asked Questions

What is the Celsius to Fahrenheit formula?
°F = (°C × 9/5) + 32. For example, 25°C × 1.8 + 32 = 77°F. The reverse is °C = (°F − 32) × 5/9.
What is normal body temperature in both scales?
37°C equals 98.6°F — the traditional “normal”. A fever threshold of 38°C is 100.4°F, which is the number most medical guidance uses.
Why does −40 convert to itself?
−40 is the unique point where both scales meet: −40°C = −40°F. It happens because the scales have different zero points and slopes, and the lines cross exactly there. It’s also a handy sanity check for any converter.
What’s a quick mental shortcut?
Double the Celsius value and add 30: 20°C → about 70°F (exact: 68°F). It’s within a few degrees for everyday weather (0–35°C) but drifts at extremes — use the exact formula when it matters.
What oven temperatures do common recipes use?
160°C = 320°F, 180°C = 356°F (usually stated as 350°F), 200°C = 392°F (≈400°F), 220°C = 428°F (≈425°F). US recipes round to the nearest 25°F, so don’t worry about single-degree precision when baking.
Is my input stored anywhere?
No — the conversion is a one-line formula running in your browser. Nothing is uploaded, stored or tracked, and the converter keeps working offline once the page has loaded.