SMOG Readability Calculator

Calculator Form

Paste Text

Manual Sentence Count Use 0 for automatic count.

Target Grade

Complex Word Option

Exclude capitalized proper nouns

Calculate SMOG Grade

Example Data Table

Formula Used

The calculator uses the widely used SMOG grade formula:

SMOG = 1.043 × √(polysyllabic words × 30 ÷ sentences) + 3.1291

A polysyllabic word has three or more syllables. The formula adjusts the complex word count to a 30 sentence sample. This helps compare passages of different lengths. The result estimates the reading grade needed to understand the text.

How to Use This Calculator

1. Paste your article, notice, guide, or page text.
2. Leave sentence count at 0 for automatic counting.
3. Add a manual sentence count when your text has unusual punctuation.
4. Select a target grade for your audience.
5. Choose whether to exclude capitalized proper nouns.
6. Press the calculate button.
7. Review the score, warning, and complex word list.
8. Download the result as CSV or PDF.

Why SMOG Readability Matters

The SMOG grade helps writers judge reading difficulty. It focuses on polysyllabic words. These are words with three or more syllables. The method estimates the years of education needed for full understanding. It is useful for health pages, policies, guides, notices, and general web content. A high score means the text may feel hard. A lower score often feels easier and faster.

What This Calculator Reviews

This tool counts sentences, words, and complex terms. It then applies the SMOG formula. It also reports averages, density, and a practical reading note. You can compare a draft with sample rows. You can export results for editors, clients, or content records. The calculator works best with thirty or more sentences. Short samples can still be checked, but the score is less stable.

How Writers Can Use the Score

Start by pasting a complete passage. Read the grade result. Then review long words and sentence patterns. Replace difficult terms when simpler terms keep the same meaning. Break long sentences into smaller ideas. Add definitions for needed technical words. Do not remove important meaning only to lower a score. Clarity should support accuracy.

Better General Content

General readers often scan pages quickly. They need clear steps, familiar words, and direct structure. A readability score gives a useful signal. It does not replace human review. Context still matters. A legal note, safety guide, or medical warning may need exact terms. In those cases, add plain explanations near the technical language.

Practical Editing Tips

Use active voice when possible. Put the main point early. Keep headings helpful. Use lists for steps. Check one section at a time. After editing, run the passage again. Compare the new grade with the earlier grade. A small improvement can make a page easier to read. The best result is text that stays correct, complete, and understandable.

Limits to Remember

SMOG is a guide, not a final judgment. It cannot know tone, layout, culture, or reader motivation. It may count unusual names as complex. It may miss familiar long words. Always read the passage aloud. Ask real users to review key pages. Combine the grade with judgment, examples, and careful proofreading before publishing any important public online material.