On the last morning of my Ahrefs subscription I burned through 400,000 API units before lunch. That was deliberate, since the budget resets monthly and expires with it, so the choice was spend it or lose it. But it produced something I had not expected to find useful: a log of 1,102 calls across those final two days, with the exact unit cost of each one attached.
Ahrefs documents the pricing model in one line. Rows times fields, minimum fifty units per billable request. That is accurate and almost useless for planning, because it tells you nothing about which tool will quietly consume your month. So I measured the 41 I actually used, out of roughly 130 the server exposes.
The short answer is that three tools ate 78 percent of everything, and the free and flat-rate surfaces together returned about a hundred times more rows per unit spent than the three expensive ones.
How the Billing Actually Works
Four mechanics, and you need all four to predict a cost.
