One is strategic, one is tactical.
Being charitable is about solving a particular, relatively immediate problem and/or reducing suffering. It may imply a sense of generosity on the part of the giver. You can think of charity as immediate or tactical giving. Charity tends towards treating symptoms and reducing immediate suffering. Charity is short term.
Philanthropy is strategic giving. It’s a more formal process which aims to tackle root causes or remove a particular problem for a specific population. Philanthropy is traditionally thought of as ‘private initiatives for public good’.
Paying for the treatment of children with polio would be a charitable act.
Paying to vaccinate children from Polio would be a philanthropic act.