(mathematics) A test for determining whether an infinite series converges, which involves calculating the limit of the ratio between the series being tested and one known to converge or diverge.

In mathematics, the comparison test, sometimes called the direct comparison test to distinguish it from similar related tests (especially the limit comparison test), provides a way of deducing whether an infinite series or an improper integral converges or diverges by comparing the series or integral to one whose convergence properties are known.