Celsius to Kelvin Converter
Convert temperatures between Celsius (°C) and Kelvin (K) with simultaneous Fahrenheit (°F) and Rankine (°R) equivalents. Supports both absolute thermodynamic temperatures (+273.15 offset) and temperature intervals (Δ°C = ΔK).
1. Temperature Conversion Inputs K = °C + 273.15
2. All-Scale Thermodynamic Equivalents Liquid Water Regime (1 atm)
| Temperature Scale | Symbol | Converted Value |
|---|---|---|
| Kelvin (SI Absolute Scale) | K | 298.15 K |
| Degrees Celsius (Metric) | °C | 25.00 °C |
| Degrees Fahrenheit (U.S. Customary) | °F | 77.00 °F |
| Degrees Rankine (U.S. Absolute Engineering) | °R | 536.67 °R |
Dual-Scale Thermometer & Reference Table -273.15 °C to +200 °C
| Celsius (°C) | Kelvin (K) | Fahrenheit (°F) |
|---|
How to Convert Celsius (°C) to Kelvin (K)
The Celsius (°C) and Kelvin (K) scales share the exact same unit magnitude—an increase of 1 °C is equal to an increase of 1 K. The only difference between the two scales is their zero point: Celsius sets 0 °C at the freezing point of water under standard atmospheric pressure, whereas Kelvin is an absolute thermodynamic scale that sets 0 K at Absolute Zero (-273.15 °C).
1. Exact Conversion Formulas
K = °C + 273.15
2. Kelvin to Celsius (Reverse Conversion):
°C = K − 273.15
3. Celsius to U.S. Fahrenheit & Rankine:
°F = (°C × 1.8) + 32
°R = (°C + 273.15) × 1.8
4. Temperature Interval / Change (ΔT):
ΔK = Δ°C (1 °C change = 1 K change)
2. Illustrative Example (Converting 25 °C Standard Room Temperature)
Suppose a chemistry problem specifies a gas sample at standard laboratory temperature of 25 °C and requires the absolute temperature in Kelvin for the Ideal Gas Law (PV = nRT):
- Step 1 — Write the formula:
K = °C + 273.15 - Step 2 — Substitute 25 °C:
K = 25 + 273.15 = 298.15 K - Step 3 — Equivalent U.S. Fahrenheit temperature:
(25 × 1.8) + 32 = 77.00 °F(536.67 °R).
3. How to Use This Converter
- Type any temperature into the Celsius (°C) field to immediately calculate the corresponding Kelvin (K) value—or type directly into the Kelvin (K) field to convert back to Celsius.
- Click any of the Benchmark pills at the top (such as Absolute Zero, Water Freezing, or Water Boiling) to load standard physical reference points.
- If you are converting a temperature change (for example, specific heat capacity in
J/(kg·K)), switch Measurement Type to Temperature Difference / Interval (ΔK = Δ°C). - Use Copy Conversion Result or Print / Save PDF to copy or print the complete four-scale breakdown.
Frequently Asked Questions (FAQ)
Why is Kelvin written as "K" without a degree (°) symbol?
Since the 13th General Conference on Weights and Measures (CGPM) in 1967, the SI base unit of thermodynamic temperature has been officially named the kelvin (symbol K) rather than "degree Kelvin" (°K) because it is an absolute scale starting at zero thermal energy rather than an arbitrary relative scale.
Can a Kelvin temperature ever be negative?
On the classical thermodynamic temperature scale, 0 K (-273.15 °C or -459.67 °F) represents Absolute Zero, the theoretical limit where a system holds only minimum quantum zero-point energy. Values below -273.15 °C cannot be reached by physical cooling.
When converting a temperature change (Δ°C to ΔK), do I add 273.15?
No. When calculating a temperature difference—such as warming water from 20 °C to 50 °C (ΔT = 30 °C)—the 273.15 offset cancels out: (50 + 273.15) − (20 + 273.15) = 30 K. Therefore, a change of 30 °C is equal to a change of 30 K.