Is it possible to copy a cell from one jupyter notebook to another?

For windows-
Use Ctrl + Shift + C to copy cells after selecting them using shift + arrow keys.

Then, switch to the notebook to which you want to copy the selected cells and go to command mode in it by pressing Esc key. Then, use Ctrl + Shift + V to paste the cells in that notebook.

Note- I have not tested this on Linux but should work just as the procedure above.

This feature has been introduced in Jupyter Notebook 5.0. Use pip install notebook --upgrade to upgrade to the latest release.

The old shortcuts C, V and X work only for copying and pasting inside one notebook. In order to do it across tabs, you should use Ctrl-C and Ctrl-V (Cmd-C and Cmd-V on Mac).

Note on multiple cells: currently (jupyter 6.0.0) on Mac+chrome using shift-click to select the cells then cmd-C does NOT work, while using the keyboard with shift-down-arrow does! (thanks drevicko for pointing this out)

With jupyter 5.0.0, copy paste of one or many cells from one notebook to another works with Cmd C Cmd V (Mac).

For copying many cells together, select the first one then the last one with shift arrow (up or down).

The tool bar does not work for this purpose.

See also https://github.com/jupyter/notebook/issues/2336

I have not done it myself though, but general practice is to avoid doing it as it can disturb the Cell JSON. It was not even possible until a few versions before. Recent Github posts has made it possible to do so though. Copy paste the cell in question to a code editor such as Atom or Sublime Text, make the changes you want to do and then paste it into the new Jupyter notebook. It should work.