Temperature Interval Converter
Convert temperature interval and difference units between Celsius, Fahrenheit, Kelvin, and Rankine scales. Free online temperature difference converter for thermodynamics and HVAC.
What Is Temperature Interval
Temperature interval measures the difference between two temperatures, not an absolute temperature value. You express temperature differences in kelvin (K), degrees Celsius (°C), degrees Fahrenheit (°F), or degrees Rankine (°R).
Temperature interval conversion differs from absolute temperature conversion. A 10°C temperature difference equals a 10 K difference. The same difference equals 18°F or 18°R. You multiply by 9/5 to convert Celsius intervals to Fahrenheit intervals.
Temperature Interval Conversion Formula
Convert temperature intervals using these relationships:
1 K = 1°C = 1.8°F = 1.8°R = 0.8°Re
To convert from Celsius interval to Fahrenheit interval:
ΔT(°F) = ΔT(°C) × 9/5
Example: A temperature rise from 20°C to 45°C represents a 25°C interval. Converting to Fahrenheit:
ΔT(°F) = 25 × 9/5 = 45°F
Verify: 20°C = 68°F and 45°C = 113°F. The difference is 113 - 68 = 45°F.
Temperature Scale Comparison
| Scale | Unit Symbol | Interval Size | Zero Point | Common Use |
|---|---|---|---|---|
| Kelvin | K | 1 (base) | Absolute zero | Science, engineering |
| Celsius | °C | 1 (same as K) | Water freezing | Worldwide, science |
| Fahrenheit | °F | 5/9 of °C | Brine freezing | United States |
| Rankine | °R | 5/9 of °C | Absolute zero | US engineering |
| Réaumur | °Re | 1.25 × °C | Water freezing | Historical, cheese |
Common Temperature Intervals
| Application | °C | °F | K |
|---|---|---|---|
| HVAC comfort range | 5 | 9 | 5 |
| Refrigerator temperature drop | 15 | 27 | 15 |
| Engine operating range | 60 | 108 | 60 |
| Water boiling to freezing | 100 | 180 | 100 |
| Industrial oven range | 200 | 360 | 200 |
Unit Conversion Factors
| From Unit | Multiply By | To Get |
|---|---|---|
| K | 1 | °C |
| K | 1.8 | °F |
| K | 1.8 | °R |
| K | 0.8 | °Re |
| °F | 5/9 | K |
| °C | 1.8 | °F |
Frequently Asked Questions
Why is temperature interval different from absolute temperature conversion
Absolute temperature conversion accounts for different zero points. Temperature interval conversion only considers unit size differences. A 10°C difference equals 10 K, but 10°C absolute equals 283.15 K.
When should I use Kelvin versus Celsius for temperature differences
Use kelvin for scientific calculations involving thermodynamic equations. Celsius intervals work for everyday applications. Both have identical interval sizes, so numerical values match.
What is the Rankine scale used for
Rankine serves US engineering applications requiring absolute temperature. Power plant calculations and aerospace engineering use Rankine. The scale combines Fahrenheit intervals with absolute zero.
How do I convert temperature coefficients between scales
Temperature coefficients use interval units. Convert using interval conversion factors. A coefficient of 0.001/°C equals 0.001/K or 0.000556/°F.
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