How can I check the speed of a local proxy service?

I’ve been testing a local proxy for a small project, and the connection sometimes feels slower than expected. I’m not sure whether it’s the proxy itself or my internet connection. How can I check the speed of a local proxy service?

I’d start with a simple baseline. Run a speed test without the proxy, then repeat it with the proxy enabled and compare latency, download speed, and upload speed. Doing several tests at different times is useful too, since network conditions can change. You don’t really need complicated tools for an initial check; consistency between multiple measurements tells you quite a lot.
 

I found it helpful to test the same destination repeatedly instead of relying on one quick result. I came across this page with info about ad verification proxy that gives a clearer picture. I also tested with and without the proxy under similar conditions, which made the comparison much easier. For the speed test itself, though, I’d record latency, download rate, upload rate, and connection failures separately.