Is anything removed from my document?

Nothing. The page splits the text into marked and unmarked segments and renders both; joining every segment reproduces your input exactly. The document is never rewritten, and the marks are only a visual layer.

How are the sentences ranked?

With the shared extractive score: TextRank centrality at weight 0.55, log term frequency divided by the square root of sentence length at 0.35, and a mild position decay at 0.10, normalised so the best sentence reads 1.000. The ranked list shows each marked sentence's score.

Why was a caption or heading marked?

Because the sentence splitter is mechanical and treats short standalone lines as sentences. A caption that repeats the document's key terms can therefore rank highly. Read the marked list with that in mind; the tool does not know what a heading is.

Can I highlight more than twelve sentences?

The page offers three, five, eight and twelve. Twelve is enough to survey a long document without marking most of it; if you need more sentences marked, the ranked list below the text always shows every score for the whole document.

Does the highlighting change how my document copies out?

The copy and download buttons produce the ranked list of marked sentences as plain text, not the document with markup. If you need the whole document, use your own editor; nothing here alters the source text.

Important Sentence Highlighter

Your text

Paste the text to highlight

How many to highlight

Selection

Start typing above — the results update as you write.

How the highlight is chosen

Sentences are ranked with the shared extractive scoring — TextRank centrality at weight 0.55, log term frequency at 0.35, position at 0.10 — and the top 5 are marked. The joining of the segments is lossless: the text around and between highlights is the original, character for character.

The ranking measures shared vocabulary, not importance. A sentence that repeats the document’s key terms will be marked even if it says nothing new, and a decisive sentence in unusual language may be left plain. Headings and captions are treated as sentences. Use the marks as a reading aid, not as a verdict on what the document means.

The important sentence highlighter marks the top-ranked sentences where they sit, so a document keeps its context: the highlight is provably lossless, and the rank and score of every marked sentence is listed beside it.

What is Important Sentence Highlighter?

Most summarisers lift sentences out of a document, which loses the paragraph they belonged to. This important sentence highlighter does the opposite: it marks the highest-ranked sentences in place. The document stays intact — headings where they were, paragraphs where they were — and the marks say which sentences the scoring picked. That makes it a reading aid rather than a rewriting tool, and it is the reason the page can claim the highlight is lossless: joining the unmarked and marked segments of the page reproduces the input character for character.

Ranking uses the shared extractive engine. Each sentence is scored 0.55 for TextRank centrality, 0.35 for log term frequency divided by the square root of its length and 0.10 for a mild position decay, then normalised so the best sentence reads 1.000. Choosing three, five, eight or twelve marks the top-ranked sentences; the count is adjusted automatically when the document has fewer sentences than requested, and every mark is listed below the text with its rank, its score and its sentence number so the selection can be audited sentence by sentence.

The in-place view answers questions a summary cannot. Does the document front-load its claims, or are the marked sentences scattered through the middle? Are whole paragraphs marked, or one sentence in each? A cluster of marks around a single term shows what the document is really about; a single mark in an otherwise unmarked section is usually a sentence that borrows the document's vocabulary rather than one that carries its weight. Since nothing is removed, the reader can judge the selection against the surrounding argument in the same glance.

The same sentence ranking doubles as a revision aid. Run three marks on a first draft, then twelve on the second, and watch which sentences gain and lose a mark as the prose changes; the tool keeps no version history, so the comparison is yours, but the marks are a cheap way to see whether the key sentences are surfacing where you intended. Paired with the summariser, which uses the identical scoring, the two views can highlight sentences and then display them out of context without re-scoring the document or disagreeing about ranks.

The heuristic is the same one the rest of this family uses, and its failure modes are stated plainly. Shared vocabulary beats importance: a sentence that repeats key terms is marked even when it adds nothing, while a decisive sentence in unusual language is left plain. Headings, captions and list items are treated as sentences by the mechanical splitter, so a caption can carry a mark. Very short documents give the ranking little to work with, and a document with one dominant term will mark the sentences that repeat it.

Nothing is uploaded. The text is processed in the browser, the ranking is deterministic so the same paste produces the same marks, and no copy of the document is stored — the marks disappear with the tab. The highlighted sentences can be copied or downloaded as a plain list, which is useful when the marks are the point and the surrounding text is not.

How to use Important Sentence Highlighter

Paste the document; the highest-ranked sentences are marked as you type.
Choose how many marks you want — three, five, eight or twelve.
Read the text with its context, then check the ranked list below the marks.
Compare the marked positions: clustering and spread both say something about the document.
Copy or download the list of marked sentences when you need them apart from the text.

When to use Important Sentence Highlighter vs related tools

Use this highlighter when the document needs to be read with its context intact. When the selection should be lifted out and read as a paragraph, the Text Summarizer returns it that way, and when it should become numbered points with their terms, the Key Points Extractor does that.

When the goal is a bottom-line brief with findings, the Executive Summary Builder reuses the same ranking in that shape, and the Bullet Point Extractor reformats prose rather than ranking it.

Privacy & Security

This tool runs entirely in your browser — no data ever leaves your device. There is no server round-trip, no upload, no logging, and no account required. Your input is processed locally using client-side JavaScript and is never stored, transmitted, or accessible to anyone else. When you close the tab, everything disappears.