Kelvin takes no degree sign at all. Write it as a plain capital K, so absolute zero is 0 K and room temperature is about 293 K. The kelvin has been an absolute scale since 1968, when "degrees Kelvin" was formally dropped. Use the ordinary letter K at U+004B.
01 All shortcuts at a glance
| Platform | Shortcut | |
|---|---|---|
| Standard US keyboard | Press K (Shift+K) directly, it's a printable key, no code needed |
|
| Windows (any app) | Win+. or Win+; emoji/symbol picker, or Character Map (Win+R → charmap) |
|
| Mac | Control+Command+Space to open Character Viewer, search "Kelvin Sign" |
|
| Word / Outlook | Type 004B, then press Alt+X |
|
| Linux (IBus) | Ctrl+Shift+U, then 004b, then Enter |
|
| HTML / CSS | K · \004b (CSS) |
02 Step by step, per platform
A real, followable procedure for every platform, not a thin restatement of the shortcut.
Any device (US keyboard)
- Press K (Shift+K), it's printed on the keycap.
- On other layouts (AZERTY, QWERTZ) the key may be in a different position or need a modifier, use the picker methods below if you can't find it.
Windows
- Open Character Map: Win+R, type charmap, press Enter.
- Search or scroll for Kelvin Sign (U+004B).
- Select it, click Copy, then paste where you need it.
Mac
- Press Control+Command+Space to open the Character Viewer.
- Type "Kelvin Sign" in the search field.
- Double-click the result to insert it.
Microsoft Word
- Type 004B.
- Press Alt+X immediately after, it converts the hex code to K.
03 Characters in this set
04 Troubleshooting & confusables
| Looks like it | But it's actually | When to use |
|---|---|---|
| K (U+212A) | The deprecated Kelvin sign | Unicode advises the plain Latin K instead, and normalisation converts this to it. |
| °K | An obsolete form abandoned in 1968 | Never in current writing. The kelvin is absolute, so no degree sign applies. |
| k lowercase | The SI prefix for kilo | Case matters. A lowercase k means a thousand, not the temperature unit. |
05 FAQ
Why is there no degree sign on kelvin?
The kelvin measures absolute temperature from zero rather than intervals above an arbitrary point. The General Conference on Weights and Measures dropped "degrees Kelvin" in 1968, leaving just K.
Which character should I use?
The ordinary Latin capital K at U+004B. Unicode has a separate Kelvin sign at U+212A but explicitly recommends against it, and normalisation folds it into the plain letter.
Is there a space before the K?
Yes, as with every SI unit, so 293 K with a non-breaking space. This is one place where the space is unambiguously correct rather than a style choice.
How do I convert Celsius to kelvin?
Add 273.15. So 0 °C is 273.15 K and absolute zero, 0 K, is minus 273.15 °C. The step size is identical in both scales.
Is the unit name capitalised?
No. The symbol is a capital K but the unit written out is lowercase, as in three hundred kelvin. SI applies this rule to every unit named after a person.