An article processing charge (APC), also known as a publication fee, is a fee which is sometimes charged to authors to make a work available open access in either an open access journal or hybrid journal. This fee is usually paid by an author's institution or research funder rather than by the author themselves. Some publishers waive the fee in cases of hardship. An article processing charge does not guarantee that the author retains copyright to the work, or that it will be made available under a Creative Commons license.
Journals use a variety of ways to generate the income required to cover publishing costs (including editorial costs, any costs of administering the peer review system), such as subsidies from institutions and subscriptions. A majority of open access journals do not charge article processing charges, but a significant and growing number of them do. They are the most common funding method for professionally published open access articles.
Different academic publishers have widely varying levels of fees, from under $100 to over $3000. High fees are sometimes charged by traditional publishers in order to publish in a hybrid open access journal, which make an individual article in a subscription journal open access. The average APC for hybrid journals has been calculated to be almost twice as high as APCs from full open access publishers. Journals with high impact factors from major publishers tend to have the highest APCs. Many open access publishers, such as PLOS, waive their APCs for those who cannot afford to pay them.
Open access articles often have a surcharge compared to a closed-access APC; for example the Proceedings of the National Academy of Sciences regularly charges $1700 per article, with a surcharge of $1350 for open-access. Similarly, AGU's Journal of Geophysical Research charges $1000 for closed-access and $3500 for open-access.