Free — no account, nothing to install
Most of them are standing outside on a phone with one bar of signal, and they have two other numbers to try. This times your website the way Google times it, on that connection, and tells you what came back without the jargon.
The full report
Those are the numbers. The report is what is behind them — what is causing each one, roughly what it is costing you in calls, and which are ten-minute fixes. Written the way I would explain it standing in your kitchen, not the way Google writes it. Yours to keep: hand it to whoever built the website, or send it back and I will tell you what I would do first.