How to Convert Celsius to Fahrenheit (and Back)
Short answer
°F = (°C × 9/5) + 32. Example: 20°C → 20 × 1.8 + 32 = 68°F. Reverse: °C = (°F − 32) × 5/9.
Weather apps switch units constantly. Memorising one formula — or a quick double-and-add trick — is enough for travel between the US and most other countries. Confirm with the unit converter.
Celsius → Fahrenheit
°F = (°C × 9/5) + 32 (same as ×1.8 + 32).
Worked: 0°C → 32°F; 100°C → 212°F; 37°C → 98.6°F.
Fahrenheit → Celsius
°C = (°F − 32) × 5/9
Worked: 68°F → 20°C; 86°F → 30°C.
Mental shortcut
Double the Celsius value and add 30 for a rough Fahrenheit estimate (20°C → ~70°F; true answer 68°F). Good enough for dressing for the weather.
Why the scales differ
Celsius sets water’s freezing and boiling points at 0 and 100. Fahrenheit sets them at 32 and 212. Neither is “wrong” — they are just different zeros and degree sizes.
Try the free temperature converter to check your numbers in seconds.
Try the free timezone converter to check your numbers in seconds.
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More worked numbers
Change one input at a time so you build intuition. Write the formula, substitute values, then confirm with the free unit converter. If the tool disagrees with your hand math, check units first (months vs years, percent vs decimal, inclusive ranges).
Common mistakes to avoid
- Mixing up percent and decimal forms (15% is 0.15, not 15).
- Using the wrong base when calculating a change or a reverse percentage.
- Ignoring fees, tax or daylight saving when the real-world total depends on them.
- Rounding too early in multi-step arithmetic.
How to practise
Invent three mini-problems from your own life — a bill, a grade, a trip, a loan quote — and solve them on paper before you open the calculator. Teaching the steps to someone else is one of the fastest ways to lock in the method.
Related tools on ViralScopeHub
After you finish this guide, explore the linked tools above and the related articles for neighbouring skills. Our calculators run privately in your browser with no sign-up, so you can check homework, budgets or work estimates without uploading data.
Quick reference card
Keep the short answer box at the top of this page as your cheat sheet. When a search result brought you here for a specific phrase, that box is designed to match the query with the formula first, then the examples below fill in the judgement calls.
Frequently asked questions
What is the formula for Celsius to Fahrenheit?
Multiply by 9/5 (or 1.8) and add 32. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
How do I convert 25°C to Fahrenheit?
25 × 1.8 + 32 = 77°F. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
What is 0°F in Celsius?
(0 − 32) × 5/9 ≈ −17.8°C. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.
Is there a converter tool?
Yes — our unit converter handles temperature and other units. Double-check units and confirm with the linked tool on this page before you rely on the figure for money or school decisions.