Sentence Diagram Generator

A sentence diagram is a graphical breakdown of a sentence's grammatical structure. In the Reed-Kellogg system — the standard format produced by this sentence diagram generator — the main subject and predicate sit on a horizontal baseline separated by a vertical line. Adjectives and adverbs hang on slanted lines beneath the words they modify, direct objects follow the verb on the baseline, and prepositional phrases attach on angled lines with the object on a horizontal line below. The result is a single figure that shows every part-of-speech relationship at a glance.

Enter any sentence and SciFig's sentence diagram generator parses the syntax, identifies the subject, predicate, objects, complements, and all modifiers, then lays them out in Reed-Kellogg format on a horizontal baseline. The diagramming sentences generator handles simple, compound, and complex sentences, places subordinate clauses on separate sub-baselines attached to the main line, and labels every element so the grammatical role of each word is clear. As a classroom sentence diagramming tool it also re-runs the same analysis on a new example in seconds, so you can build a worksheet of progressively harder structures without laying out a single baseline by hand.

In a Reed-Kellogg sentence diagram the subject appears to the left of the baseline and the predicate (verb) to the right, separated by a full vertical line crossing the baseline. A predicate nominative or predicate adjective follows the verb and is separated from it by a backward-slanting line. Modifiers of the subject hang on slanted lines below the subject, and modifiers of the verb hang below the verb. The sentence diagram generator places all of these elements automatically.

Single-word adjectives and adverbs appear on slanted lines beneath the nouns or verbs they modify — a direct visual link that makes the modifier relationship easy to see. Prepositional phrases attach below the modified word: the preposition sits on a diagonal line and the object of the preposition sits on a horizontal line beneath it. This sentence to diagram generator places every modifier and phrase in the correct position, including stacked modifiers and chains of prepositional phrases.

Yes. For compound sentences the diagramming sentences generator draws two full baselines joined by a dotted step-line labeled with the coordinating conjunction. For complex sentences, subordinate clauses receive their own sub-baseline attached to the main diagram by a dotted line to the word or position where the clause functions — as noun, adjective, or adverb. Compound-complex sentences combine both structures. The sentence diagrammer labels every connection so the hierarchical syntax is clear.

A complete Reed-Kellogg sentence diagram produced by this sentence diagram maker can include nouns, pronouns, verbs, adjectives, adverbs, prepositions, conjunctions, interjections, and articles — covering all traditional parts of speech. Direct objects, indirect objects, predicate nominatives, predicate adjectives, appositives, participial phrases, gerund phrases, and infinitive phrases each have a designated position in the grammar diagram generator's output, following the rules first established by Alonzo Reed and Brainerd Kellogg. As a complete sentence diagramming tool, it scales cleanly from simple subject-verb sentences to compound-complex structures.