How is the Polish Fog index calculated?

It uses the standard Gunning Fog structure: 0.4 times the sum of words-per-sentence and the percentage of hard words. The Polish adaptation defines a hard word as one with four or more syllables instead of the English three, because Polish words run longer.

Why four syllables instead of three?

Many ordinary, easily understood Polish words have three syllables, so the English threshold would flag too much common vocabulary as difficult. Raising the bar to four syllables keeps the index aligned with perceived difficulty in Polish.

How are Polish syllables counted?

A syllable corresponds to a vowel nucleus, so the tool counts vowel groups using the Polish vowels a ą e ę i o ó u y. Consecutive vowels are treated as a single nucleus, and every word counts as at least one syllable.

What does the Fog number mean?

It approximates years of schooling. A Fog of 8 suggests text readable around the eighth year of education, while 14 or more indicates demanding, academic prose. Lower numbers mean broader accessibility.

Does my text get uploaded?

No. All counting and scoring run locally in your browser. Nothing is sent to a server, so the tool is safe for confidential or unpublished Polish content.

Polish Gunning Fog Adaptation

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The Gunning Fog index estimates how many years of education a reader needs to understand a passage on the first pass. Because Polish words are longer and more syllable-rich than English ones, this tool adapts the “hard word” threshold so the index stays meaningful for Polish text.

How it works

The formula is the classic Gunning Fog:

0.4 × ( (words / sentences) + 100 × (hardWords / words) )

Words are Polish tokens, sentences come from terminal punctuation (. ! ? …), and a hard word is one with four or more syllables. Syllables are counted by vowel groups using the Polish vowels a ą e ę i o ó u y, with adjacent vowels forming a single nucleus. The result approximates the school grade or years of education required.

Example

Short sentences built from one- and two-syllable words yield a low Fog index (broadly accessible). Long sentences dense with four-plus-syllable nouns and participles — common in legal and academic Polish — push the index up sharply, signalling text that demands a higher reading level.

Notes

Use this to keep public-information, marketing, or instructional Polish copy within reach of a general audience. Treat the number as a comparative guide between drafts rather than an exact grade, and combine it with human review for final decisions.