Temperature Conversion Chart
Use this printable temperature chart for common Celsius, Fahrenheit, Kelvin, and Rankine reference points. The formulas show the offsets clearly, which is where most temperature conversion mistakes happen.
| Celsius | Fahrenheit | Kelvin | Rankine | Note |
|---|---|---|---|---|
| -40 | -40.0 | 233.15 | 419.67 | Celsius and Fahrenheit meet here. |
| -20 | -4.0 | 253.15 | 455.67 | Common reference point. |
| 0 | 32.0 | 273.15 | 491.67 | Water freezes at standard pressure. |
| 10 | 50.0 | 283.15 | 509.67 | Common reference point. |
| 20 | 68.0 | 293.15 | 527.67 | Common reference point. |
| 25 | 77.0 | 298.15 | 536.67 | Common reference point. |
| 30 | 86.0 | 303.15 | 545.67 | Common reference point. |
| 37 | 98.6 | 310.15 | 558.27 | Common reference point. |
| 40 | 104.0 | 313.15 | 563.67 | Common reference point. |
| 60 | 140.0 | 333.15 | 599.67 | Common reference point. |
| 80 | 176.0 | 353.15 | 635.67 | Common reference point. |
| 100 | 212.0 | 373.15 | 671.67 | Water boils at standard pressure. |
C to F
F = C x 9 / 5 + 32
F to C
C = (F - 32) x 5 / 9
C to K
K = C + 273.15
Temperature scales require both scaling and an origin
Celsius and Fahrenheit do not share a zero point or degree interval, so a correct conversion is an affine transformation rather than a single multiplier. Kelvin and Rankine begin at absolute zero but use different interval sizes.
Useful formula and scale checks
These values help catch a missing offset or a reversed fraction before a chart result is copied into another calculation.
- -40
- -40 degrees Celsius equals -40 degrees Fahrenheit.
- 0 C
- 32 F and 273.15 K.
- 20 C
- 68 F and 293.15 K.
- 100 C
- 212 F and 373.15 K.
- One Celsius interval
- Equals one kelvin interval.
- One Fahrenheit interval
- Equals one Rankine interval.
Apply the offset in the right order
To convert Fahrenheit to Celsius, subtract 32 before multiplying by 5/9. Reversing that order changes the reference origin and gives the wrong answer even if the interval ratio is correct.
To move from Celsius to kelvin, add 273.15. The degree interval has the same size, so no additional scale multiplier is needed for that pair.
Distinguish definitions from physical observations
The mathematical relationships among the scales are defined. The chart's water freezing and boiling notes are practical reference points, not universal constants for every sample and environment.
Phase-change temperatures depend on pressure and material conditions. Use a calibrated method and the applicable scientific procedure when the value is evidence, rather than treating a general conversion chart as a measurement protocol.
Use absolute temperature where a formula requires it
Many thermodynamic relationships require kelvin because ratios and zero-temperature meaning rely on an absolute scale. Substituting a Celsius number into such a formula changes the physical interpretation.
A converted kelvin value cannot be below zero for a physical thermodynamic temperature. A negative result indicates an invalid input for that context or a formula/unit mistake that needs review.
Worked check: convert 68 F
- 1Subtract the Fahrenheit offset: 68 - 32 = 36.
- 2Scale the interval: 36 × 5/9 = 20 degrees Celsius.
- 3Add the kelvin offset: 20 + 273.15 = 293.15 kelvin. The chart displays reference values with fixed decimal formatting for consistent lookup.
Precision and chart-use limits
- A conversion can preserve the numeric relationship between scales, but it cannot improve thermometer calibration, sensor accuracy, sample stability, or the number of meaningful digits in the source reading.
- Rankine is included as an absolute scale using Fahrenheit-size intervals. Confirm the expected scale before copying a value into technical work because K and degrees R are not interchangeable numbers.
- Use the live converter for an arbitrary value. Use this chart for common checkpoints, formula review, and a printable reference rather than interpolating between distant rows.
Sources and definitions
- NIST: SI unit of thermodynamic temperature
Authoritative background for kelvin, Celsius intervals, and thermodynamic-temperature usage.
Temperature chart questions
What is the Celsius to Fahrenheit formula?
Use F = C x 9 / 5 + 32. The multiplication changes the size of the degree interval, and the plus 32 handles the offset between the Celsius and Fahrenheit zero points.
What is the Fahrenheit to Celsius formula?
Use C = (F - 32) x 5 / 9. Subtracting 32 removes the Fahrenheit offset before the degree interval is scaled into Celsius.
Why does temperature need more than multiplication?
Temperature scales have different zero points, so Celsius and Fahrenheit conversions need an offset. Kelvin and Rankine are absolute scales, but they still connect to Celsius and Fahrenheit through interval size and offset.
Where are Celsius and Fahrenheit equal?
Celsius and Fahrenheit are equal at -40 degrees. That point is useful for checking whether a temperature conversion formula is being applied in the right order.
Can I use this chart for scientific calculations?
Use Kelvin for most scientific formulas that require absolute temperature. The chart helps with reference values, while the live converter is better for arbitrary temperatures and exact table output.
Who maintains this page
Ownership and review
Written and maintained by the Toolarithm editorial team. No review date is shown without a maintained editorial record. No independent professional review is claimed.
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