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
The planned app subtracts parent-confirmed substitutions, omissions, skipped words or lines, and parent-supplied words. Insertions and repetitions may be noted without subtracting from the attempted-word count. A self-correction within the stated convention is counted correct and can remain visible as a note.
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.