The current peer review system is under stress from ever increasing numbers of publications, the proliferation of open-access journals and an apparent difficulty in obtaining high-quality reviews in due time. At its core, this issue may be caused by scientists insufficiently prioritising reviewing. Perhaps this low prioritisation is due to a lack of understanding on how many reviews need to be conducted by researchers to balance the peer review process. I obtained verified peer review data from 142 journals across 12 research fields, for a total of over 300,000 reviews and over 100,000 publications, to determine an estimate of the numbers of reviews required per publication per field. I then used this value in relation to the mean numbers of authors per publication per field to highlight a ‘review ratio’: the expected minimum number of publications an author in their field should review to balance their input (publications) into the peer review process. On average, 3.49 ± 1.45 (SD) reviews were required for each scientific publication, and the estimated review ratio across all fields was 0.74 ± 0.46 (SD) reviews per paper published per author. Since these are conservative estimates, I recommend scientists aim to conduct at least one review per publication they produce. This should ensure that the peer review system continues to function as intended. View Full-Text