FORCAST Readability Formula Calculator Online

FORCAST Readability Formula

Introduction

The FORCAST Readability Formula is unique among readability tests—it's the only formula specifically designed for technical documents rather than running narrative text. Developed by HumRRO (Human Resources Research Organization) for the United States Army, FORCAST was created to assess the readability of forms, training manuals, surveys, and other technical materials that soldiers encounter.

Unlike other readability formulas that count unfamiliar words or rely on sentence length, FORCAST takes a different approach by counting single-syllable words. This makes it particularly effective for evaluating technical writing where short, precise terms are common.

What Makes FORCAST Different?

FORCAST stands out from other readability formulas in several key ways:

1. Ignores Sentence Length: Most readability formulas heavily weigh sentence length, but FORCAST doesn't consider it at all. This makes it ideal for bulleted lists, forms, and technical instructions.

2. Counts Single-Syllable Words: Instead of counting difficult or unfamiliar words, FORCAST counts simple, single-syllable words. The assumption is that technical documents with more single-syllable words are easier to read.

3. Designed for Technical Content: FORCAST is specifically calibrated for technical documents, training materials, and instructional content—not novels, essays, or narrative text.

4. Limited Range: FORCAST can only calculate reading levels from 5th grade to college level. It cannot assess materials below a 5th-grade reading level.

The FORCAST Formula

The FORCAST formula is remarkably simple:

FORCAST Grade Level = 20 - (N ÷ 10)

Where:

• N = Number of single-syllable words in a 150-word sample
• The result is a U.S. Grade Level

How to Calculate FORCAST

Follow these steps to calculate the FORCAST readability score:

Step 1: Select a sample of 150 words from your text. For longer documents, you may want to take multiple samples and average the results.

Step 2: Count the number of single-syllable words in your sample.

Step 3: Divide the number of single-syllable words by 10.

Step 4: Subtract the result from 20.

The final number is your FORCAST Grade Level.

Example Calculation

Let's say you have a 150-word sample from a technical manual and you count 90 single-syllable words:

• N = 90 (single-syllable words)
• N ÷ 10 = 90 ÷ 10 = 9
• 20 - 9 = 11

FORCAST Grade Level = 11 (11th grade reading level)

Interpreting FORCAST Scores

FORCAST scores represent the U.S. grade level a reader must have completed to understand the text:

Recommended FORCAST Level

For most technical writing intended for a general audience, a FORCAST grade of 9-10 is recommended. This ensures that the majority of adults can understand your technical documents without difficulty.

Military training materials, which were the original target of FORCAST, typically aim for a grade level of 7-8 to ensure comprehension across diverse educational backgrounds.

When to Use FORCAST

FORCAST is particularly useful for:

• Training Manuals: Employee handbooks, military training materials, equipment manuals
• Forms and Surveys: Application forms, questionnaires, data collection instruments
• Technical Instructions: Assembly instructions, operating procedures, safety guidelines
• Policy Documents: Standard operating procedures (SOPs), compliance documents
• Instructional Materials: Step-by-step guides, troubleshooting procedures

When NOT to Use FORCAST

FORCAST is not appropriate for:

• Narrative text, fiction, or creative writing
• Academic essays or research papers
• News articles or magazine content
• Elementary-level materials (below 5th grade)
• Content where sentence structure and flow are important

For these types of content, consider using other readability formulas like Flesch-Kincaid, Gunning Fog, or SMOG Index.

Improving Your FORCAST Score

To improve your FORCAST score and make technical content more readable:

1. Use Simple Words: Replace multi-syllable technical jargon with simpler alternatives when possible

   • "Use" instead of "utilize"
   • "Help" instead of "facilitate"
   • "Show" instead of "demonstrate"

2. Explain Technical Terms: When technical terms are necessary, provide simple definitions

3. Use Short, Clear Words: Choose words that are both short and precise

4. Test Multiple Samples: For longer documents, test several 150-word samples to ensure consistency

5. Balance Precision and Simplicity: Technical accuracy shouldn't be sacrificed, but aim for the simplest way to convey precise information

Limitations of FORCAST

While FORCAST is valuable for technical content, it has some limitations:

• Cannot assess below 5th grade: FORCAST scores are clamped at grade 5 minimum
• Single metric focus: Only considers word length (syllables), ignoring other readability factors
• Context matters: A low FORCAST score doesn't guarantee comprehension if concepts are inherently complex
• Not for narrative text: FORCAST wasn't designed for stories, essays, or flowing prose

History and Development

FORCAST was developed by the Human Resources Research Organization (HumRRO), which was founded to conduct research and develop tools for the U.S. Army. The military needed a quick, reliable way to assess whether training materials were readable for soldiers with diverse educational backgrounds.

The researchers recognized that technical military documents—forms, field manuals, standard operating procedures—had different characteristics than the narrative texts most readability formulas were designed to evaluate. Thus, FORCAST was born as a specialized tool for specialized content.

Further Reading

For more information about the FORCAST Readability Formula, consult these resources:

• FORCAST Readability Formula - ReadabilityFormulas.com
• FORCAST Readability Formula - Originality.AI
• FORCAST Readability Formula - Readable