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Convert Kelvin to Fahrenheit instantly with our free online calculator. Essential for translating scientific absolute temperatures into the everyday Fahrenheit scale used in the United States for weather, cooking, and engineering.
0 K
−459.67 °F (Absolute Zero)
273.15 K
32 °F (Water Freezes)
373.15 K
212 °F (Water Boils)
Formula: °F = (K − 273.15) × 9/5 + 32
| Kelvin (K) | Fahrenheit (°F) | Context |
|---|---|---|
| 0 K | −459.67 °F | Absolute zero |
| 77 K | −321.07 °F | Liquid nitrogen boiling point |
| 184 K | −128.20 °F | Lowest recorded Earth temperature |
| 233.15 K | −40.00 °F | K and °C share the same reading (−40) |
| 255.37 K | 0.00 °F | Zero degrees Fahrenheit |
| 273.15 K | 32.00 °F | Water freezes (standard pressure) |
| 293.15 K | 68.00 °F | Comfortable room temperature |
| 298.15 K | 77.00 °F | Standard reference temperature (STP) |
| 310.15 K | 98.27 °F | Human body temperature (~98.6 °F) |
| 373.15 K | 212.00 °F | Water boils (standard pressure) |
| 505.37 K | 450.00 °F | Typical baking / oven temperature |
| 1,811 K | 2,800 °F | Iron melting point |
The Kelvin scale is the thermodynamic (absolute) temperature scale adopted as the SI base unit for temperature. Named after Lord Kelvin (William Thomson, 1824–1907), it begins at absolute zero (0 K), the point at which all classical molecular motion ceases. Each Kelvin increment is the same size as one degree Celsius, but unlike Celsius the scale has no negative values. This property makes Kelvin indispensable for the ideal gas law, Stefan–Boltzmann radiation equation, Boltzmann distribution, and virtually all equations in thermodynamics and statistical mechanics.
The Fahrenheit scale was proposed in 1724 by the Polish-German physicist Daniel Gabriel Fahrenheit. On this scale, water freezes at 32 °F and boils at 212 °F under standard atmospheric pressure, giving a 180-degree span between those two reference points. Fahrenheit remains the customary temperature scale in the United States for weather forecasts, cooking, HVAC settings, and medical readings.
The relationship between the two scales is: °F = (K − 273.15) × 9/5 + 32. Because a Fahrenheit degree is 5/9 the size of a Kelvin (or Celsius) degree, the Fahrenheit scale stretches wider: the 100 K gap between water's freezing and boiling points spans 180 °F. Converting between these scales bridges the gap between the international scientific community (which uses Kelvin) and everyday temperature expression in the US.
The formula is: °F = (K − 273.15) × 9/5 + 32. Subtract 273.15 to convert Kelvin to Celsius, multiply by 9/5 to scale the degree size, then add 32 to shift to the Fahrenheit zero point.
Question: Convert the boiling point of water from Kelvin to Fahrenheit.
Question: What is normal body temperature in Fahrenheit?
Question: A cryogenics lab stores samples at 77 K. What is that in Fahrenheit?
For a rough estimate, subtract 273, double the result, and add 30. This gives an approximation within a few degrees for moderate temperatures. For instance, 300 K: 300 − 273 = 27, doubled = 54, plus 30 = 84 °F (exact: 80.33 °F). The shortcut works because doubling is close to multiplying by 1.8, and adding 30 is close to adding 32.
| Description | Kelvin | Fahrenheit |
|---|---|---|
| Very cold winter day | 253 K | −11.47 °F |
| Freezing point of water | 273.15 K | 32.00 °F |
| Cool spring morning | 283.15 K | 50.00 °F |
| Comfortable room | 293.15 K | 68.00 °F |
| Warm summer day | 303.15 K | 86.00 °F |
| Hot desert afternoon | 318.15 K | 113.00 °F |
| Water boils | 373.15 K | 212.00 °F |
| Material / Event | Kelvin | Fahrenheit |
|---|---|---|
| Liquid helium boils | 4.2 K | −452.11 °F |
| Liquid nitrogen boils | 77 K | −321.07 °F |
| Dry ice sublimates | 194.65 K | −109.30 °F |
| Lead melts | 600.61 K | 621.43 °F |
| Aluminum melts | 933.47 K | 1,220.58 °F |
| Iron melts | 1,811 K | 2,800.13 °F |
| Tungsten melts | 3,695 K | 6,191.33 °F |
| Sun surface | 5,778 K | 9,940.73 °F |
| Food Reference | Kelvin | Fahrenheit |
|---|---|---|
| Refrigerator (safe zone) | 277 K | 39.53 °F |
| Danger zone begins | 313.15 K | 104.00 °F |
| Poultry safe internal temp | 347.04 K | 165.00 °F |
| Beef medium-rare | 328.15 K | 131.00 °F |
| Bread baking | 463.15 K | 374.00 °F |
| Pizza oven | 533.15 K | 500.00 °F |
Laboratory data is recorded in Kelvin, but US audiences and some engineering teams expect Fahrenheit. Researchers publishing results, presenting at conferences, or writing press releases for American media routinely convert Kelvin findings to Fahrenheit for accessibility.
Aerospace, automotive, and industrial engineers often work with thermodynamic data in Kelvin but must specify operational limits, material tolerances, and safety thresholds in Fahrenheit for US-based manufacturing floors and regulatory compliance documents.
Phase diagrams, heat treatment curves, and diffusion coefficients are defined in Kelvin. Foundry operators and heat-treat technicians in the US convert these specifications to Fahrenheit for furnace setpoints, quenching schedules, and quality inspection reports.
Climate models and satellite radiometric data use Kelvin. Meteorologists translating these datasets into local US weather forecasts must convert to Fahrenheit so the public can relate to reported temperatures in a familiar scale.
The correct formula is °F = (K − 273.15) × 9/5 + 32. Converting to Celsius first, then to Fahrenheit, avoids order-of-operations errors.
273.15 K = 32 °F and 373.15 K = 212 °F. If your result does not land between these for moderate temperatures, recheck your math.
One Kelvin degree equals 1.8 Fahrenheit degrees. This is why a 100 K span (water freezing to boiling) produces a 180 °F span.
Skipping the −273.15 step gives wildly wrong answers. K × 9/5 + 32 is not the correct formula. You must subtract 273.15 first.
The correct unit is simply "kelvin" (symbol K) with no degree sign. Writing "°K" is outdated and incorrect under SI conventions since 1967.
Kelvin is an absolute scale. Temperatures below 0 K do not exist in classical thermodynamics. If you have a negative value, you may be working in Celsius already.
Use the formula °F = (K − 273.15) × 9/5 + 32. First subtract 273.15 from the Kelvin value to get Celsius, then multiply by 9/5 and add 32 to get Fahrenheit. For example, 300 K = (300 − 273.15) × 9/5 + 32 = 80.33 °F.
Absolute zero (0 K) equals −459.67 °F. This is the lowest possible temperature, where all molecular motion theoretically ceases. It is a fundamental limit in thermodynamics and cannot be reached in practice.
273.15 K equals exactly 32 °F. This is the freezing point of water at standard atmospheric pressure. It serves as a key reference point for calibrating thermometers and verifying temperature conversions.
Kelvin is an absolute scale starting at absolute zero, making it essential for thermodynamic equations, gas laws, and radiation calculations. Unlike Fahrenheit, Kelvin has no negative values, which simplifies ratios and proportions in physics and chemistry.
Standard room temperature of 68–72 °F corresponds to approximately 293–295 K (or 20–22 °C). In scientific literature, 298.15 K (25 °C / 77 °F) is commonly used as the standard reference temperature for experiments and material property tables.
No. Kelvin values are always non-negative (starting at 0 K), while the equivalent Fahrenheit value at 0 K is −459.67 °F. As Kelvin increases, Fahrenheit increases faster (due to the 9/5 multiplier), so the two scales never share the same numerical reading.
Use the inverse formula: K = (°F − 32) × 5/9 + 273.15. Subtract 32 from the Fahrenheit value, multiply by 5/9 to get Celsius, then add 273.15 to arrive at Kelvin. For example, 212 °F = (212 − 32) × 5/9 + 273.15 = 373.15 K.
Material science uses a wide Kelvin range. Cryogenic testing occurs below 120 K (−244 °F). Steel is commonly heat-treated at 1,100–1,300 K (1,520–1,880 °F). Tungsten melts at 3,695 K (6,191 °F). Kelvin is preferred because thermodynamic property equations require absolute temperature.
This calculator uses the standard conversion formula °F = (K − 273.15) × 9/5 + 32 based on the internationally defined relationship between the Kelvin and Fahrenheit scales. For mission-critical applications in aerospace, medical devices, or industrial process control, always verify conversions against calibrated instrumentation and applicable standards.