Currently means at this moment: "she is currently in Berlin." Presently traditionally means soon or shortly: "he will arrive presently." The two have been drifting together for centuries, and presently is now widely used to mean "now" as well — which makes it ambiguous. If you mean now, currently is the word that cannot be misread.
The core difference
Currently is unambiguous: it means at the present moment. Presently has two live meanings — "soon" (the traditional sense) and "now" (the newer one) — and a reader cannot always tell which you intend.
The traditional split
- currently — at this moment: The line is currently closed.
- presently — in a short while: The doctor will see you presently.
Why it is genuinely ambiguous
Consider "the committee is presently reviewing the proposal". Is the review happening now, or about to start? Both readings are defensible, and in a contract, a status report or a schedule that ambiguity has consequences.
What to write
Use currently for now and soon or shortly for the future. That leaves presently for cases where its slightly formal, old-fashioned tone is what you want, and where the timing is not load-bearing. This is not a rule about correctness — both senses are established — but about not making the reader guess.
