How do I convert fahrenheit to celsius?

By Paulo de VriesLast verified 2026-05-204 sources~4 min readhigh consensus

Quick answer

Exact: °C = (°F − 32) × 5/9. Quick approx: subtract 30 then halve (°C ≈ (°F − 30) ÷ 2). Common: 350°F = 177°C; 400°F = 205°C; 165°F (poultry safe) = 74°C; 212°F = 100°C; 32°F = 0°C.

5 variables shift this number4 cited sources3 common mistakes addressed~4 min read read below

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The full answer

The formula

Exact: °C = (°F − 32) × 5/9 Or equivalently: °C = (°F − 32) ÷ 1.8

Quick mental math: °C ≈ (°F − 30) ÷ 2 - Accurate within ~2°C for most kitchen temperatures - Easy to do in your head while cooking

Reverse direction: °F = (°C × 9/5) + 32, or °F = (°C × 1.8) + 32

Where the formula comes from

Daniel Gabriel Fahrenheit (1724) calibrated his scale so 0°F = a brine mixture's freezing point and 96°F = "blood-warm" (his estimate of body temp; actually 98.6°F).

Anders Celsius (1742) calibrated: 0°C = water freezes; 100°C = water boils (at sea level). His original scale was inverted (0 = boil); Linnaeus flipped it in 1745.

The conversion is a linear transformation: F and C scales share the same physical reality but with different zero points (freezing offset by 32) and different unit sizes (1°F = 5/9 of 1°C).

Critical cooking temperatures (memorize these)

Fahrenheit	Celsius	What it is
32°F	0°C	Water freezing
40°F	4°C	Safe refrigerator temp
140°F	60°C	Danger zone upper bound
145°F	63°C	Safe internal: fish, beef medium-rare
160°F	71°C	Safe internal: ground meat
165°F	74°C	Safe internal: ALL poultry (USDA mandatory)
195°F	90°C	Safe internal: dark-meat chicken (preferred)
200°F	93°C	Safe internal: pork shoulder, brisket
212°F	100°C	Water boiling (sea level)
250°F	121°C	Slow cooking (BBQ low-and-slow)
300°F	149°C	Low oven
325°F	163°C	Moderate oven (cakes)
350°F	177°C	Standard baking
375°F	191°C	Bread, biscuits
400°F	205°C	Roasting vegetables, pizza
425°F	218°C	Crispy roasted things
450°F	232°C	Pizza, broiling
500°F	260°C	Pizza oven (modest)
550°F	288°C	Max home oven
800°F	427°C	Wood-fired pizza
900°F	482°C	Steel-grate-shut grill

Common rookie mistakes

Forgetting the 32 offset (just multiplying by 5/9 gives wildly wrong results)
Confusing direction (F→C uses subtract-then-multiply; C→F uses multiply-then-add)
Using approximation for sensitive cooking (sourdough proofing, custards, ganache) — use exact formula
Confusing oven dial markings: many US ovens use Fahrenheit; EU/UK ovens use Celsius. Check before recipe-following!

Cross-reference: see /pages/how-to-convert/celsius-to-fahrenheit for reverse direction + /pages/what-temperature-for/baking-bread for baking-specific temps.

Time ranges by condition

Condition	Duration	Note
Exact formula	°C = (°F − 32) × 5/9	—
Quick mental math	°C ≈ (°F − 30) ÷ 2	Within ~2°C
Critical: poultry safe	165°F = 74°C	—
Water freezing	32°F = 0°C	—
Standard baking	350°F = 177°C	—
Water boiling (sea level)	212°F = 100°C	—
Pizza oven	500°F = 260°C	—
Wood-fired pizza	800°F = 427°C	—

What changes the time

Direction (F to C vs C to F). F to C: subtract 32 first, then multiply by 5/9. C to F: multiply by 9/5 first, then add 32.
Approximation vs exact. For oven temps ±5°C tolerance: approximation OK. For ganache, custards, ferments: use exact.
Altitude (boiling point). Water boils at 212°F (100°C) at sea level only. -1°F (-0.5°C) per 1000ft altitude.
Oven calibration. Most home ovens are off ±25°F (±14°C). Use an oven thermometer; convert AFTER calibration.
Conversion app vs mental math. Use phone for precision-critical recipes (custards, soufflés). Mental math fine for roasting + most baking.

Common questions

Why does the formula use 5/9 instead of 5/8?

Because the Fahrenheit scale has 180 degrees between water's freezing (32°F) and boiling (212°F), while the Celsius scale has only 100 degrees between freezing (0°C) and boiling (100°C). The ratio is 100/180 = 5/9. So 1°F is exactly 5/9 of 1°C. The offset of 32 accounts for where the freezing point sits in each scale. Using 5/8 would give an answer ~12% too high.

Can I just halve the fahrenheit number to get celsius?

Only approximately — and only after subtracting 30. The shortcut °C ≈ (°F − 30) ÷ 2 is accurate within ~2°C for most kitchen temperatures (300-450°F range). For 350°F: shortcut gives (350-30)/2 = 160°C; actual is 177°C. The shortcut is off by 17°C here — fine for "roughly preheat" but not for ganache (1°C off ruins texture). For precision, always use the exact formula or a phone app.

My recipe says 180°C — what is that in fahrenheit?

180°C = 356°F. This is the European/UK standard for "moderate oven" — equivalent to American "350°F" recipes. The 6°F difference is generally within oven calibration tolerance, so following 180°C as 350°F in your American oven is fine. Other common European temps: 160°C = 320°F (slow); 200°C = 392°F ≈ 400°F (hot); 220°C = 428°F ≈ 425°F (very hot).

Sources

We cite primary research, expert practice, and authoritative reference. Higher-tier sources weighted heavier. See methodology.

Tier 1 · peer-reviewed / governmentalTier 2 · editorial referenceTier 3 · named practitioner

T1NIST (National Institute of Standards + Technology) — Authoritative conversion factors
T1USDA FSIS Safe Minimum Cooking Temperatures — Critical food-safety temps in both units
T2King Arthur Baking temperature conversion chart — Baking-specific conversion table
T2BIPM (International Bureau of Weights + Measures) — Official SI unit definitions for Celsius (kelvin-based)

Verify this answerEvery number, range, and recommendation on this page traces to a cited source listed above. Click any source to read the original. See how we verify for the full source-tier discipline, or browse the citation graph to see every source we cite across 291 answers.

What could change this answer

honest uncertainty

We don’t know your specific equipment, ingredient batch, or environment. This answer is the best directional estimate from cited sources. Here’s where it’s less certain:

5 factors shift the answer. Your specific direction (f to c vs c to f), approximation vs exact, altitude (boiling point) (and more) can move this estimate in either direction. The table below shows the documented ranges.
Range spans 8 documented conditions. Pick the row that matches your scenario; halfway between two rows is your best estimate. The widest condition you can imagine is the safer upper bound.
Treat as a directional starting point. Real-world equipment, ingredient batch, and ambient conditions cause natural variance the table cannot capture. Use sensory checks (sight, smell, touch, internal temperature when relevant) alongside this answer — not instead of it.
Backed by 4 cited sources — verify if precision matters. See the Sources section for primary references. Cross-check the cited materials when stakes are high: commercial production, food safety, allergens, dietary or medical considerations.
Verified 13 days ago. If you found a better-sourced answer or our answer no longer matches reality, tell us — corrections are public and dated. The page exists to be accurate, not to be unchanged.

Cite this page

de Vries, P. (2026). How do I convert fahrenheit to celsius?. AskedWell. Retrieved 2026-06-02, from https://askedwell.com/pages/how-to-convert/fahrenheit-to-celsius

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Last verified: 2026-05-20 · Published 2026-05-20

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