How Type Fast Works

Confidence scores: how we measure each key

Confidence is the core metric Type Fast uses to measure your proficiency with each key. It represents how close you are to your target typing speed for that specific key: we divide your target time per keystroke by your actual average time. If your target is 200 ms per keystroke and you average 200 ms, your confidence is 100%. If you average 400 ms — twice as slow — your confidence is 50%.

Raw timing is noisy, though. One slow keystroke because you hesitated shouldn't tank your score. So Type Fast uses exponential smoothing: each new keystroke contributes only 10% to your running average while the previous average contributes 90%. That gives a stable measure that adjusts as your real speed changes while filtering out random outliers.

Every key falls into one of three zones: below 60% confidence needs focus, 60–85% is the practicing zone, and 85% or above counts as mastered.

The focus-key system

At any moment, your weakest key becomes the focus key. The text generator then ensures that 80–100% of the words in your session contain that specific key. Struggling with R? You'll see text like "red river road rather render rare reader." That concentrated exposure accelerates improvement on your weakest link far faster than random practice would.

As soon as that key improves enough that it's no longer your weakest, focus automatically shifts to whatever is now holding you back. Your practice time is always allocated to wherever it does the most good.

How new keys are unlocked

New keys are introduced in order of how often they appear in English — starting with E, then T, A, O, I, N, S, H, R, and so on down to Z. Learning high-frequency letters first means you can type real English words much sooner, which keeps practice engaging.

The system won't add a new key until two things are true: all your current keys reach 85% confidence, and each has at least five recorded attempts so the data is statistically reliable. These guardrails stop the trainer from promoting you on a few lucky keystrokes — we'd rather you solidify your foundation than rush ahead with shaky habits.

How practice text is generated

There are no pre-written sentences. Every lesson is generated from your current key set, so you never practice keys you haven't learned. The generator works in priority order: first it filters real English words that can be spelled with your current keys (with just the home row, that's words like "all," "fall," "glad," "salad," and "flask"). If too few qualify, it pulls from an extended vocabulary, then falls back to pronounceable pseudo-words built from common letter pairs like "th," "er," "in," and "an," and finally to simple key combinations.

We work hard to use real words because typing "the" thousands of times turns it into a single chunk in your muscle memory rather than three separate keystrokes. You're not just learning where keys are — you're learning how they flow together in real text.

Progress tracking and skill levels

Type Fast records smoothed timing, confidence, accuracy, attempts, and your best-ever confidence for every key, plus your WPM, accuracy, and duration for each session. It all persists in your browser's local storage — your progress is never lost between sessions, and it never leaves your device.

As you master more keys you climb through levels: Novice (home row), Beginner (8+ keys), Intermediate (15+), Advanced (20+), and Expert (all 26). The methodology draws on established learning science — spaced repetition (weak keys reviewed more often), deliberate practice (the focus-key system), progressive overload (adding keys only when you're ready), and immediate feedback on every keystroke.