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Suno AI Prompt & Lyrics Character Limits: The Complete Cheat Sheet (2026)

Published 2026-07-03 · ~7 min read

Short answer: on the current Suno models (V4.5, V4.5+, V5, V5.5), custom lyrics cap at 5,000 characters and the style prompt caps at 1,000 characters. On the older models (V3.5, V4), those caps drop to 3,000 and 200. Titles are capped at 80 characters via API. Every character counts — spaces, line breaks, and [Verse] tags included.

Here's the full field-by-field breakdown, split into the limits AI Music API actually enforces in code (we're an independent developer platform, not affiliated with Suno) and the limits reported in the Suno app itself.

The cheat sheet

API limits (AI Music API — enforced by our request validation)

These are hard limits. Exceed one and the request fails with a 400 validation_error before any credits are charged.

| Field | V3.5 / V4 | V4.5 / V4.5+ / V5 / V5.5 | | --- | --- | --- | | prompt (custom lyrics) | 3,000 chars | 5,000 chars | | tags (style description) | 200 chars | 1,000 chars | | negative_tags (styles to avoid) | 200 chars | 200 chars | | gpt_description_prompt (simple mode song description) | 400 chars | 400 chars | | title | 80 chars | 80 chars | | webhook_url | 1,024 chars | 1,024 chars |

One quirk worth knowing: the chirp-v4-5-all model variant validates at the older limits (3,000 lyrics / 200 style), not the V4.5 limits. If you're using it, budget accordingly.

Suno app limits (per third-party testing)

| Field | V4 & older | V4.5 / V5 / V5.5 | | --- | --- | --- | | Style prompt | 200 chars | ~1,000 chars | | Custom lyrics | 3,000 chars | 5,000 chars | | Title | 80 chars | 100 chars |

Sources: HookGenius's field-by-field limit tests and Blake Crosley's Suno V5.5 guide. Suno doesn't publish an official limits table, so app-side numbers can shift between UI releases — when in doubt, test in the playground.

The two columns line up almost exactly, with one difference: the app allows 100-character titles on newer models, while our API enforces 80 across all versions. And the failure behavior differs in an important way, covered below.

Why limits matter for programmatic generation

If you're generating songs one at a time in a UI, a character cap is a minor annoyance. If you're generating thousands of tracks programmatically — user-submitted lyrics in a consumer app, LLM-written lyrics in a pipeline, templated jingles at scale — limits become a reliability problem:

  • LLM-generated lyrics routinely blow past 5,000 characters. A model asked for "a full song with 4 verses, chorus, bridge, and outro" frequently produces 5,500+ characters once structure tags are included.
  • User input is unbounded. Someone will paste their 12,000-character epic. Your integration decides whether that's a clean error or a mystery failure.
  • Style prompts inflate silently. Concatenating genre + mood + instrumentation + vocal descriptors from a form can quietly cross 1,000 characters.

Validating client-side before you submit is the difference between a helpful "your lyrics are 312 characters over" message and a failed generation your user has to retry.

What happens when you exceed a limit

The two surfaces fail differently, and the difference matters:

In the Suno app, third-party testing reports that overlong style text is silently truncated — the generation runs, but with a cut-off prompt. Your carefully ordered style descriptors past the cap simply never reach the model.

Via AI Music API, over-limit requests are rejected explicitly. You get an HTTP 400 with a machine-readable body:

{
  "type": "validation_error",
  "error": "The prompt character length for chirp-v5 should less than 5000."
}

The same shape covers every field, e.g. for style tags on an older model:

{
  "type": "validation_error",
  "error": "The tags character length for chirp-v3-5 should less than 200."
}

No credits are deducted for a validation failure, and nothing is sent to the model. Explicit rejection beats silent truncation for programmatic work: you'd rather retry with trimmed input than ship a track generated from half a prompt.

Tips to compress prompts

When you're bumping against the style limit (especially the 200-character cap on V3.5/V4):

  1. Use comma-separated tags, not sentences. "melancholic indie folk, fingerpicked acoustic guitar, female vocal, 90 BPM" (74 chars) carries the same signal as a 200-character prose description. The model reads descriptors, not grammar.
  2. Cut filler adjectives. "Beautiful", "amazing", "high-quality" spend characters without steering the output. Genre, instrumentation, tempo, mood, and vocal type are what move the needle.
  3. Move structure into the lyrics field. Section tags like [Chorus], [Bridge], [Guitar Solo] belong inline in prompt, where the budget is 3,000–5,000 characters — don't burn style-field characters describing song structure.
  4. Use negative_tags for exclusions. "No EDM, no autotune" as negative_tags: "edm, autotune" is cheaper and more reliable than negation inside the style prompt.
  5. Pick a newer model when you need room. Moving from V4 to V4.5+ or V5 quintuples your style budget (200 → 1,000) and adds 2,000 lyric characters.

Limits and extend / continuation workflows

Character limits apply per request, not per finished song. That's the escape hatch for long-form work:

  • A single generation is capped by its model's lyric limit (3,000 or 5,000 characters).
  • To go longer, generate the first section, then extend from a timestamp (continue_at + continue_clip_id) with the next block of lyrics — which gets its own fresh 5,000-character budget.
  • Each extension is a separate request validated independently, so a 15,000-character libretto is three chained extend calls, not one giant one.
  • When the chain is done, a concatenation step stitches the segments into one continuous track.

Practical note echoed by community testing: even under the 5,000 cap, extremely dense lyrics can get rushed pacing as the model squeezes everything into one track length. For anything past ~3,000 characters of lyrics, chunk-and-extend usually sounds better than one maxed-out request.

Enforce limits client-side (JavaScript)

Fifteen lines that catch every over-limit field before you spend a network round trip:

const ADVANCED = ["chirp-v4-5", "chirp-v4-5-plus", "chirp-v5", "chirp-v5-5"];

function validateSunoRequest({ mv, prompt = "", tags = "", title = "" }) {
  const advanced = ADVANCED.includes(mv);
  const limits = {
    prompt: advanced ? 5000 : 3000, // custom lyrics
    tags: advanced ? 1000 : 200,    // style description
    title: 80,
  };
  const errors = [];
  for (const [field, max] of Object.entries(limits)) {
    const len = { prompt, tags, title }[field].length; // UTF-16 units, matches server
    if (len > max) errors.push(`${field}: ${len}/${max} chars (${len - max} over)`);
  }
  return { ok: errors.length === 0, errors };
}

String.prototype.length counts UTF-16 code units — the same measure our server-side validation uses — so a client-side pass here guarantees a server-side pass on these fields.

Try it with 30 free credits

Every new AI Music API account gets 30 free credits at signup — enough to test the limits above against V5 and V5.5 yourself, no payment method required. One POST request returns a task ID; a webhook or polling call returns your finished track. Full request schema in the API docs.

FAQ

Does the character limit include spaces?

Yes. Spaces, line breaks, punctuation, and structure tags like [Verse] or [Chorus] all count toward the limit. The validation measures the raw string length of the field exactly as you submit it.

Do non-Latin characters count differently?

Mostly no. Chinese, Japanese, Korean, Cyrillic, Hebrew, and Arabic characters each count as one character — a 3,000-character Mandarin lyric sheet is measured the same as a 3,000-character English one. The exception: characters outside the Basic Multilingual Plane (emoji, some rare CJK ideographs) count as two, because limits are measured in UTF-16 code units (JavaScript .length).

Is there a minimum prompt length?

No enforced minimum. Very short style prompts (a single genre word) work fine — you just cede more creative decisions to the model.

Does the lyrics limit apply in simple (description) mode?

Simple mode uses a different field with a different cap: the song description (gpt_description_prompt) is limited to 400 characters on every model version via our API. The model writes the lyrics itself, so the 3,000/5,000 lyric limits don't apply to your input.

Do [Verse] and [Chorus] tags reduce my usable lyric space?

Yes — tags count like any other text. A heavily annotated song structure can consume 200–400 characters of your budget. That's normally negligible against 5,000 but noticeable against 3,000 on older models.

What's the title limit — 80 or 100?

Via AI Music API: 80 characters on all model versions (enforced in validation). In the Suno app, third-party testing reports 100 on V4.5 and newer. If your pipeline needs to work with both, treat 80 as the safe ceiling.

Will the limits change with future model versions?

They have with every major version so far (V4.5 raised lyrics 3,000 → 5,000 and style 200 → 1,000). We update this page and our validation together when a new version ships, so the API error messages are always the ground truth. If a number here ever seems stale — test in the playground.

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