A speed test is a tool used to measure the performance of an internet connection. It typically assesses two main factors: download speed, which indicates how quickly data can be received, and upload speed, which shows how fast data can be sent. Users can run these tests through various websites or applications to determine their connection's efficiency. These tests are important for understanding how well an internet service provider (ISP) is delivering service. Factors like network congestion, distance from the router, and the type of connection (e.g., fiber, cable, or DSL) can affect the results.