10fastfingers.com

Why accuracy not shown in 1-minute tests unlike that in Text Practice?
Accuracy is the percentage of correct keystrokes pressed to the sum of all keystrokes pressed(corrected + uncorrected).
Backspace keystroke is not taken into consideration.

Accuracy is quite a helpful metric. Hope it will be shown in 1-minute tests.
I think if I improve my accuracy, I'll further increase my typing speed.

This would be a great feature and I too am sad that it's not included, but for now just focus on completing tests with at least a 95% accuracy rating. I have found that by concentrating on accuracy you become more consistent and, because you spend less time correcting errors, your typing speed will increase without much effort at all.

Hope this was of help to you even though I could not answer your question.