The 60-second formula
For a full 60-second sample:
If a child reaches 47 words and the parent confirms one error, the sample is 46 WCPM.
Samples shorter than one minute
When a passage ends early and at least 20 seconds were read, normalize the count:
For example, 35 correct words in 45 seconds becomes 46.7 before the app applies its stated rounding rule. Very short samples should be marked invalid rather than stretched into a confident result.
Accuracy
With 46 correct words out of 47 attempted, accuracy is about 97.9%.
What counts as an error in Fluency Lens
The adult taps each printed word that should count as an error. The app subtracts one error for each marked word at or before the confirmed last word reached. Fluency Lens does not classify substitutions, omissions, insertions, repetitions, or self-corrections separately in the current release.
What WCPM cannot tell you
One WCPM value cannot diagnose a condition, measure all comprehension, or establish an official reading grade. Passage difficulty, familiarity, fatigue, environment, and scoring choices all matter. Keep the passage band and administration visible beside every result.