Online Tool Store
Sentence Diagrammer
Break a sentence into subject, predicate, objects, and modifiers, showing how the clauses relate — useful for grammar teaching and editing.
🔒 This tool runs entirely in your browser. Your files are never uploaded to a server.
Education
Sentence Diagrammer
Frontend preview — no upload or external service.
Diagram
Subject "The old bridge" with a relative clause "that crosses the river"; predicate "was rebuilt" in the passive, modified by "last spring".
How the Sentence Diagrammer works
- Enter one sentence at a time — diagramming works badly on paragraphs.
- Read the main subject and predicate first, then how the modifiers attach.
- Use it on sentences that felt hard to read; the diagram usually shows why.
FAQ
Why diagram sentences at all?
Because it makes structure visible. A sentence that reads awkwardly often has a modifier attached to the wrong noun or three clauses stacked, and the diagram shows which — a spellchecker never will.
Does it handle complex sentences?
Multiple clauses and standard modifiers, yes. Deliberately ambiguous sentences have more than one valid parse, and any parser picks one — which is itself a useful signal that the sentence needs rewriting.
Is this still taught?
Less than it once was, and it remains useful for editing, for teaching English as an additional language, and for anyone learning why a sentence they wrote does not work.
How we compare
| Feature | Online Tool Store | Pen and paper | A classroom platform |
|---|---|---|---|
| Shows clause relationships | ✓ | ✗ | ✓ |
| Flags ambiguous parses | ✓ | ✗ | Sometimes |
| Text stays local | ✓ | ✓ | ✗ |
| No account | ✓ | ✓ | ✗ |
Sentence Diagrammer is most useful on sentences that read badly — the structure usually shows the fault a grammar checker misses entirely.