Flesch-Kincaid Grade Level & Flesch Reading Ease Score Calculator

Evaluate prose readability using ASL (words/sentence) and ASW (syllables/word).

Flesch-Kincaid U.S. Grade Level
8.87 grade level
Flesch Reading Ease (0–100) 61.92 score
Average Sentence Length (ASL) 17.11 words/sent
Average Syllables per Word (ASW) 1.51 syl/word
Inputs
words
Total word count in the passage.
sentences
Total sentence count in the passage.
syllables
Total syllable count across all words.
Results & Graph
Flesch-Kincaid U.S. Grade Level
8.87 grade level
Flesch Reading Ease (0–100)
61.92 score
Average Sentence Length (ASL)
17.11 words/sent
Average Syllables per Word (ASW)
1.51 syl/word

Flesch-Kincaid U.S. Grade Level

Graph 1 • Total Words Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 grade level 12.6 grade level 25.2 grade level 50%: 23.33 grade level 23.3 50% 75%: 13.13 grade level 13.1 75% 100%: 8.87 grade level 8.9 100% 125%: 6.98 grade level 7.0 125% 150%: 6.28 grade level 6.3 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
Flesch-Kincaid U.S. Grade Level 8.87 grade level Flesch Reading Ease (0–100) 61.92 score Average Sentence Length (ASL) 17.11 words/sent Average Syllables per Word (ASW) 1.51 syl/word
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
Flesch-Kincaid U.S. Grade Level8.87 grade levelFlesch Reading Ease (0–100)61.92 scoreAverage Sentence Length (ASL)17.11 words/sentAverage Syllables per Word (ASW)1.51 syl/word
Summary: At 17.1 words/sentence and 1.51 syllables/word, Flesch-Kincaid Grade Level is 8.9 and Flesch Reading Ease is 61.9/100.
Summary: At 17.1 words/sentence and 1.51 syllables/word, Flesch-Kincaid Grade Level is 8.9 and Flesch Reading Ease is 61.9/100.
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Formula & Mathematical Methodology: Flesch-Kincaid Readability Formula

ReadingEase = 206.835 − 1.015(Words/Sentences) − 84.6(Syllables/Words)
FKGrade = 0.39(W/S) + 11.8(Syl/W) − 15.59
ReadingEase = 206.835 − 1.015(Words/Sentences) − 84.6(Syllables/Words); FK_Grade = 0.39(W/S) + 11.8(Syl/W) − 15.59
  • totalWords: Total Words (words)
  • totalSentences: Total Sentences (sentences)
  • totalSyllables: Total Syllables (syllables)

Rounding: Standardized test and time rules follow official scoring rubrics; continuous outputs round to 2 decimal places.

Worked Example: Benchmark Scenario: Flesch-Kincaid Readability

Evaluate prose readability using ASL (words/sentence) and ASW (syllables/word).

  1. Enter your raw test counts, credit hours, or schedule parameters.
  2. Evaluate the formula: ReadingEase = 206.835 − 1.015(Words/Sentences) − 84.6(Syllables/Words); FK_Grade = 0.39(W/S) + 11.8(Syl/W) − 15.59.
  3. Inspect the primary score/duration, supporting metrics, and 3 SVG graphs.
Result: Computes Flesch-Kincaid Readability via ReadingEase = 206.835 − 1.015(Words/Sentences) − 84.6(Syllables/Words); FK_Grade = 0.39(W/S) + 11.8(Syl/W) − 15.59.

Frequently Asked Questions

How does the Flesch-Kincaid Grade Level & Flesch Reading Ease Score Calculator calculate results?

It evaluates ReadingEase = 206.835 − 1.015(Words/Sentences) − 84.6(Syllables/Words); FK_Grade = 0.39(W/S) + 11.8(Syl/W) − 15.59 directly in your browser and updates three custom SVG visualizations in real time.

Can I use Goal Seek to find the exact score or hours I need?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any input variable.

Are my academic or schedule inputs kept private?

Yes. All calculations run 100% locally in your browser.

Education · Writing, Research & Psychometrics

Flesch-Kincaid Grade Level & Flesch Reading Ease Score Calculator: inputs, method, and how to read the result

Evaluate prose readability using ASL (words/sentence) and ASW (syllables/word).

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Total Words: Total word count in the passage.
  • Total Sentences: Total sentence count in the passage.
  • Total Syllables: Total syllable count across all words.

What the calculation includes

With the default values shown, Flesch-Kincaid U.S. Grade Level is 8.87 grade level. The calculation follows Flesch-Kincaid Readability Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Total Words from 650 words to 715 words changes Flesch-Kincaid U.S. Grade Level from 8.87 grade level to 7.92 grade level. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses official published scoring scales, Carnegie unit conventions, and ISO calendar rules.
  • Official standardized test equating curves vary slightly by test form administration date.

Scope: Global Academic, Psychometric & ISO 8601 Time Standard Check the assumptions and limitations against your situation before relying on the estimate.

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