How are words correct per minute calculated?

Subtract uncorrected errors from words attempted, multiply by 60, then divide by elapsed seconds. With 120 words, 10 errors and 120 seconds, the result is 110 × 60 / 120 = 55 WCPM.

How is reading accuracy calculated?

Accuracy is (words attempted − uncorrected errors) / words attempted × 100. For 120 words and 10 errors, it is 110 / 120 × 100 = approximately 91.667%. This is a descriptive proportion, not a grade or proficiency classification.

How should I count self-corrections?

Keep self-corrected words separate from uncorrected errors. A self-corrected word remains in the correct-word count for WCPM and accuracy. Count each affected word once, and use observation rules appropriate to your own record. Uncorrected errors plus self-corrected words cannot exceed words attempted.

What does the self-correction ratio mean?

The tool shows self-corrected words : (uncorrected errors + self-corrected words), normalized to 1:x. Ten errors and two self-corrections produce 2:12, or 1:6. With no self-corrections the ratio is undefined and shown as N/A. No assessment threshold is applied.

How are multiple sessions combined?

History totals pool words, errors, self-corrections and elapsed time before calculating WCPM and accuracy. They do not average individual session rates. Different passages and observation conditions may not be comparable; pooled counts are descriptive only.

Where is the session history saved?

History stays in page memory unless you enable Save history on this device. Saving merges additions and removals with the latest usable device record, preserving other entries and unknown fields. Unusable saved data is retained until you explicitly forget it. Turning saving off or choosing Forget device-saved history removes the saved copy and keeps current entries on this page. CSV exports every current entry. No passage text or reader name is required; the calculator uploads nothing.

Can I correct or remove a history entry?

Load copy places an entry back in the calculator without changing the original. Edit and add it as a new snapshot, then remove the old entry if desired. Undo restores the last add, remove or clear operation on the current page. Up to 500 entries are supported.

What are the input and precision limits?

Enter 1–1,000,000 attempted words, nonnegative whole error and self-correction counts, and elapsed seconds greater than zero and at most 86,400. Seconds support three decimal places. Displayed metrics round to three decimals. Zero elapsed time and inconsistent word counts return an error.

Does this replace a running-record assessment or timer?

It calculates accuracy, WPM, WCPM and the self-correction ratio from counts and elapsed seconds you supply. It does not time reading, count words from a passage, analyze miscues or comprehension, assign reading levels, or implement Fountas & Pinnell, Reading Recovery or national assessment rules.

Reading Session Calculator

Enter observed words, uncorrected errors, self-corrected words and elapsed seconds. See the arithmetic behind WCPM and accuracy, then record session snapshots and export a local history.

Observed reading session

Session label (optional)Words attemptedUncorrected errorsSelf-corrected wordsElapsed seconds

Count each word once. Errors here mean words left incorrect; self-corrected words belong in the separate correction count and remain correct for WCPM. Apply your own observation rules consistently. Enter 1–1,000,000 words and positive elapsed seconds up to 86,400, with millisecond precision. No passage text or reader name is required.

Words correct per minute55110 correct words in 120 seconds

Accuracy91.667%110 of 120 words

Self-correction ratio1:6SC : (uncorrected errors + SC)

Transparent arithmetic

Purple: correct words, including self-corrections. Brown: uncorrected errors. The bar is a count comparison, not a proficiency scale.

Correct words = 120 − 10 = 110
WCPM = 110 × 60 ÷ 120 = 55
Accuracy = 110 ÷ 120 × 100 = 91.667%
Attempted WPM = 120 × 60 ÷ 120 = 60

Self-correction ratio: 2 : (10 + 2), normalized to 1:6. Metrics round to three decimals. A ratio is descriptive and has no assessment threshold here.

Adding a session captures a snapshot. Later input edits do not change saved entries. Repeated sessions with the same counts are kept as separate entries.

Calculation summary

Reading session: Example passage
Words attempted: 120
Uncorrected errors: 10
Self-corrected words: 2
Elapsed seconds: 120
Correct words: 110
Words correct per minute: 55
Attempted words per minute: 60
Accuracy: 91.667%
Self-correction ratio SC:(E+SC): 1:6

WCPM = (words - uncorrected errors) × 60 / elapsed seconds
Accuracy = (words - uncorrected errors) / words × 100
Self-corrected words remain in the correct-word count. Errors exclude self-corrections; count each word once.
Displayed metrics round to three decimals.
Descriptive arithmetic from user-observed word counts and elapsed time. No grade level, diagnosis, placement or proficiency classification.

Session history · 0 / 500

Save history on this device

Off by default. Enabling this saves counts, timestamps and optional labels in this browser. Turning it off explicitly forgets the saved copy and keeps the current page’s entries. Unusable saved data is retained until you choose Forget device-saved history. Saving merges your additions and removals with the latest device record; other page entries and unknown fields are preserved. Export before leaving when saving is off. Use labels appropriate for a shared device.

No sessions yet. Add the current calculation to start a history.

Selectable complete history CSV

"Session label","Recorded at UTC","Words attempted","Uncorrected errors","Self-corrected words","Elapsed seconds","Correct words","WCPM","Attempted WPM","Accuracy percent","SC ratio denominator (1:x)"

Downloads are browser handoffs; this page cannot confirm saving. Complete CSV is available for manual recovery. Undo restores the last add, remove or clear operation on this page. CSV includes every entry, with formula-like labels prefixed by an apostrophe. A recorded timestamp is when the entry was added, not necessarily when reading occurred.

Descriptive arithmetic from user-observed word counts and elapsed time. No grade level, diagnosis, placement or proficiency classification. Calculations and history remain in your browser.

Common questions

How are words correct per minute calculated?: Subtract uncorrected errors from words attempted, multiply by 60, then divide by elapsed seconds. With 120 words, 10 errors and 120 seconds, the result is 110 × 60 / 120 = 55 WCPM.
How is reading accuracy calculated?: Accuracy is (words attempted − uncorrected errors) / words attempted × 100. For 120 words and 10 errors, it is 110 / 120 × 100 = approximately 91.667%. This is a descriptive proportion, not a grade or proficiency classification.
How should I count self-corrections?: Keep self-corrected words separate from uncorrected errors. A self-corrected word remains in the correct-word count for WCPM and accuracy. Count each affected word once, and use observation rules appropriate to your own record. Uncorrected errors plus self-corrected words cannot exceed words attempted.
What does the self-correction ratio mean?: The tool shows self-corrected words : (uncorrected errors + self-corrected words), normalized to 1:x. Ten errors and two self-corrections produce 2:12, or 1:6. With no self-corrections the ratio is undefined and shown as N/A. No assessment threshold is applied.
How are multiple sessions combined?: History totals pool words, errors, self-corrections and elapsed time before calculating WCPM and accuracy. They do not average individual session rates. Different passages and observation conditions may not be comparable; pooled counts are descriptive only.
Where is the session history saved?: History stays in page memory unless you enable Save history on this device. Saving merges additions and removals with the latest usable device record, preserving other entries and unknown fields. Unusable saved data is retained until you explicitly forget it. Turning saving off or choosing Forget device-saved history removes the saved copy and keeps current entries on this page. CSV exports every current entry. No passage text or reader name is required; the calculator uploads nothing.
Can I correct or remove a history entry?: Load copy places an entry back in the calculator without changing the original. Edit and add it as a new snapshot, then remove the old entry if desired. Undo restores the last add, remove or clear operation on the current page. Up to 500 entries are supported.
What are the input and precision limits?: Enter 1–1,000,000 attempted words, nonnegative whole error and self-correction counts, and elapsed seconds greater than zero and at most 86,400. Seconds support three decimal places. Displayed metrics round to three decimals. Zero elapsed time and inconsistent word counts return an error.
Does this replace a running-record assessment or timer?: It calculates accuracy, WPM, WCPM and the self-correction ratio from counts and elapsed seconds you supply. It does not time reading, count words from a passage, analyze miscues or comprehension, assign reading levels, or implement Fountas & Pinnell, Reading Recovery or national assessment rules.

Descriptive arithmetic from user-observed word counts and elapsed time. No grade level, diagnosis, placement or proficiency classification.