< class="breadcumb-title text-anim" data-cue="slideInUp" data-delay="300">Temperature Converter
Temperature Converter — Celsius, Fahrenheit, Kelvin & 6 More Scales | ASLI FORM

Temperature Converter

Convert between Celsius, Fahrenheit, Kelvin, Rankine, Réaumur, Delisle, Newton, Rømer, and Gas Mark with exact algebraic formulas.

Conversion Formula
°F = (100°C × 9/5) + 32 = 212°F
All 9 Scales at Once

Key Temperature Reference Points

Common benchmarks
Reference PointCelsiusFahrenheitKelvinDescription
Absolute Zero-273.15°C-459.67°F0KLowest possible temperature
Water Freezing0°C32°F273.15KFreezing point of water at 1 atm
Human Body37°C98.6°F310.15KAverage body temperature
Room Temp20-25°C68-77°F293-298KComfortable indoor temperature
Water Boiling100°C212°F373.15KBoiling point at sea level
Oven Baking180°C356°F453.15KStandard baking temperature
Pizza Oven450°C842°F723.15KWood-fired pizza oven
Iron Melting1538°C2800°F1811.15KMelting point of iron
Sun Surface5505°C9941°F5778KSun's photosphere
Lightning Bolt30000°C54032°F30273KTemperature of lightning

All 9 Temperature Scales Explained

From modern scientific standards to historical scales used across civilizations, our converter supports every world-known temperature scale with complete historical accuracy.

Cooking Temperature Guide

With Gas Marks
Gas MarkCelsiusFahrenheitDescriptionCommon Use
1/4110°C225°FVery SlowDrying, slow cooking
1/2120°C250°FVery SlowMeringues, drying herbs
1140°C275°FSlowSlow roasting, casseroles
2150°C300°FSlowStewing, braising
3160°C325°FModerateCakes, gentle baking
4180°C350°FModerateMost baking, cookies
5190°C375°FModerate HotPies, pastries
6200°C400°FHotBread, pizza
7220°C425°FHotRoasting meats
8230°C450°FVery HotPizza, quick roasts
9240°C475°FVery HotNeapolitan pizza
10260°C500°FMaximumHighest oven temp

Meat Doneness Temperatures

Safe internal temps
DonenessCelsiusFahrenheitCharacteristics
Rare (Beef)52-55°C125-130°FCool red center, very soft
Medium Rare55-60°C130-140°FWarm red center, tender
Medium60-65°C140-150°FPink center, firm
Medium Well65-69°C150-155°FSlightly pink, firm
Well Done71+°C160+°FBrown throughout, firm
Chicken (Safe)74°C165°FUSDA safe temperature
Pork (Safe)63°C145°FSafe with rest time
Fish63°C145°FFlakes easily

Weather Temperature Feelings

How it feels
CelsiusFahrenheitDescriptionWhat to Wear
-40 to -20°C-40 to -4°FExtreme ColdFull winter gear, heavy coat
-20 to -10°C-4 to 14°FVery ColdWinter jacket, gloves, hat
-10 to 0°C14 to 32°FColdWarm coat, scarf
0 to 10°C32 to 50°FCoolSweater, light jacket
10 to 18°C50 to 65°FMildLight sweater, long sleeves
18 to 24°C65 to 75°FComfortableT-shirt, light clothing
24 to 30°C75 to 86°FWarmSummer clothing, shorts
30 to 38°C86 to 100°FHotLight clothing, stay hydrated
38 to 45°C100 to 113°FVery HotAvoid sun, AC recommended
45+°C113+°FExtreme HeatHeat danger, stay indoors

Scientific Temperature Extremes

Fascinating facts
PhenomenonCelsiusKelvinDescription
Absolute Zero-273.15°C0KLowest possible temperature, zero molecular motion
Liquid Nitrogen-196°C77KUsed in cryogenics, medical preservation
Liquid Oxygen-183°C90KRocket fuel, medical applications
Dry Ice (CO₂)-78.5°C194.65KSublimates directly to gas
Mercury Melting-38.83°C234.32KOnly metal liquid at room temp
Gold Melting1064°C1337KMelting point of pure gold
Tungsten Melting3422°C3695KHighest melting point of any metal
Sun Surface5505°C5778KSun's photosphere
Sun Core15 million°C15 millionKNuclear fusion site
Lightning Bolt30000°C30273K5x hotter than sun's surface

Exact Conversion Formulas

Unlike simple multiplication-based conversions, temperature scales require algebraic formulas because they have different zero points and scale intervals. Here are the exact mathematical relationships used in our converter.

How to Use This Converter

Our temperature converter is designed for scientists, engineers, chefs, students, and anyone working with temperature data. Here's how to get the most out of it.

  • Select Source Scale Choose the scale you're converting from (e.g., Celsius) in the first dropdown.
  • Select Target Scale Pick the scale you want to convert to (e.g., Fahrenheit) in the second dropdown.
  • Enter Temperature Value Type any number, including decimals and negative values. Results appear instantly.
  • View All 9 Scales The "All 9 Scales" section shows your value converted to every scale at once.
  • Use Swap Button Click the swap button to instantly reverse the conversion direction.
  • Study the Formula The exact mathematical formula is displayed below for verification and learning.

Why Professionals Choose Our Converter

Built with scientific precision and premium design, our temperature converter is trusted by scientists, engineers, chefs, and educators worldwide.

  • Scientific Precision 10-digit accuracy using exact algebraic formulas from NIST and BIPM standards.
  • All 9 World Scales From modern Celsius/Fahrenheit to historical Réaumur, Delisle, Newton, and Rømer.
  • All Scales at Once View your temperature converted to all 9 scales simultaneously — no extra clicks needed.
  • Works Offline All calculations run locally in your browser. Perfect for labs and field work.
  • Zero Tracking No cookies, no analytics, no data collection. Your conversions stay private.
  • Comprehensive References Includes cooking guides, meat temps, weather scales, and scientific extremes.

Frequently Asked Questions

Our converter supports all 9 world-known temperature scales:
  • Celsius (°C) — Used by most of the world, scientific standard
  • Fahrenheit (°F) — Used in USA, Liberia, and some Caribbean nations
  • Kelvin (K) — Scientific absolute temperature scale
  • Rankine (°R) — Absolute scale using Fahrenheit degrees
  • Réaumur (°Ré) — Historical French scale (0-80)
  • Delisle (°De) — Historical Russian scale (inverted)
  • Newton (°N) — Historical scale by Isaac Newton
  • Rømer (°Rø) — Historical Danish scale
  • Gas Mark — UK cooking oven scale
This gives you 72+ possible conversions between these scales.
The formula is:
°F = (°C × 9/5) + 32
For example, to convert 100°C to Fahrenheit:
• Multiply 100 × 9/5 = 180
• Add 32 → 212°F

The reverse (Fahrenheit to Celsius) uses:
°C = (°F − 32) × 5/9
Our converter handles this automatically with scientific precision to 10 significant digits.
Kelvin is an absolute temperature scale starting at absolute zero (where molecular motion stops), while Celsius starts at the freezing point of water.
K = °C + 273.15
Key facts:
  • 0 K = -273.15°C (absolute zero)
  • 0°C = 273.15 K (water freezes)
  • A 1°C change = a 1 K change (same interval)
  • Kelvin has no degree symbol (°), just "K"
Kelvin is the SI unit of temperature and is used in all scientific work.
Absolute zero is the lowest possible temperature where all molecular motion theoretically stops. It equals:
  • -273.15°C (Celsius)
  • -459.67°F (Fahrenheit)
  • 0 K (Kelvin)
  • 0 °R (Rankine)
It is a theoretical limit that cannot be physically reached, though scientists have come within billionths of a degree. At absolute zero, a substance has minimum possible energy.
Yes. Our converter uses exact algebraic formulas from official metrology standards including NIST (National Institute of Standards and Technology) and BIPM (International Bureau of Weights and Measures).

Results are accurate to 10 significant digits, suitable for:
  • Scientific research and academic papers
  • Engineering calculations
  • Laboratory work
  • Industrial applications
  • Culinary precision cooking
Temperature conversions use exact formulas rather than approximations, ensuring consistent accuracy across the entire temperature range.
Gas Mark is a temperature scale used on gas ovens primarily in the United Kingdom and some Commonwealth countries. It ranges from 1/4 to 10.

Key reference points:
  • Gas Mark 1 = 140°C / 275°F (Slow)
  • Gas Mark 4 = 180°C / 350°F (Moderate — most common)
  • Gas Mark 6 = 200°C / 400°F (Hot)
  • Gas Mark 9 = 240°C / 475°F (Very Hot)
Our converter shows Gas Mark equivalents when temperatures fall within the oven range (110-260°C), making it perfect for following British recipes.
These are historical temperature scales that were used before modern standardization:
  • Réaumur (1730) — Used across Europe until the 19th century, especially in France. 0°Ré = freezing water, 80°Ré = boiling water.
  • Delisle (1732) — Created by French astronomer Joseph-Nicolas Delisle, used in Russia for over 100 years. It's inverted — higher numbers mean colder temperatures!
  • Newton (1700) — Created by Sir Isaac Newton. 0°N = freezing water, 33°N = boiling water.
  • Rømer (1701) — Danish astronomer Ole Rømer's scale. Influenced Fahrenheit's later design.
Including these scales helps historians, educators, and researchers working with historical scientific texts and instruments.
Yes. Our converter handles all temperature ranges including negative values.

Examples:
  • -40°C = -40°F (the only value where Celsius equals Fahrenheit)
  • -273.15°C = 0 K (absolute zero)
  • -89.2°C (coldest recorded temp on Earth, Antarctica)
Simply enter any negative number with a minus sign (-) and the converter will calculate correctly. Note that Kelvin and Rankine cannot be negative — values below absolute zero will show "Invalid".
Yes. All calculations happen locally in your browser. There is no server-side processing, no API calls, and no internet dependency for conversions.

This makes the tool perfect for:
  • Laboratory work in shielded rooms
  • Field research in remote locations
  • Classrooms with limited connectivity
  • Travel where internet is unavailable
  • Situations requiring data privacy
Once the page loads, you can disconnect from the internet and continue using all features.
Here are essential temperatures to memorize:
  • -273.15°C / 0 K — Absolute zero
  • 0°C / 32°F — Water freezes
  • 20-25°C / 68-77°F — Room temperature
  • 37°C / 98.6°F — Human body temperature
  • 100°C / 212°F — Water boils at sea level
  • 180°C / 356°F — Standard baking temperature
  • 5505°C / 9941°F — Sun's surface
See our "Key Temperature Reference Points" table above for a complete quick-reference chart.
Yes, the ASLI FORM Temperature Converter is 100% free forever. There are:
  • No registration requirements
  • No usage limits
  • No subscription fees
  • No hidden charges
  • No advertisements
  • No data collection
Our mission is to provide premium scientific tools that everyone can use without barriers. The tool is supported by our broader digital services platform.
Absolutely. Our converter is perfect for culinary use:
  • Convert between Celsius and Fahrenheit for international recipes
  • View Gas Mark equivalents for British recipes
  • Check meat doneness temperatures for safe cooking
  • Set precise temperatures for sous vide cooking
  • Convert candy-making temperatures accurately
See our dedicated Cooking Temperature Guide and Meat Doneness sections above for detailed culinary references.

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