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Claude Haiku 4.5 vs Claude Opus 5.5

Claude Opus 5.5 grades higher overall (99.5 against 57.0). Claude Haiku 4.5 costs 75% less for the same work.

Claude Haiku 4.5

by Anthropic · #42 of 67 overall

Coming soon · price at launch
Context
195K
Input / 1M
$1.00
Output / 1M
$5.00

Claude Opus 5.5

by Anthropic · #1 of 67 overall

Coming soon · price at launch
Context
1M
Input / 1M
$4.00
Output / 1M
$20.00

Better overall

Claude Opus 5.5

Grade 57.0 vs 99.5

Cheaper

Claude Haiku 4.5

75% less, $2.00 vs $8.00 blended

Larger context

Claude Opus 5.5

195K vs 1M tokens

Head to head

Public benchmarks. Longer is better; each value links to its source.

LMArena TextElo-style rating · LMArena (CC BY 4.0) · Oct 15, 2026
Claude Haiku 4.5Claude Haiku 4.5: 1,414
Claude Opus 5.5Claude Opus 5.5: 1,508
LMArena WebDevElo-style rating · LMArena (CC BY 4.0) · Oct 13, 2026
Claude Haiku 4.5Claude Haiku 4.5: 1,330
Claude Opus 5.5Claude Opus 5.5: 1,811
LMArena CodingElo-style rating · LMArena (CC BY 4.0) · Oct 15, 2026
Claude Haiku 4.5Claude Haiku 4.5: 1,482
Claude Opus 5.5Claude Opus 5.5: 1,545
SWE-bench Verified% of issues resolved · SWE-bench · Oct 15, 2025 · reference
Claude Haiku 4.5Claude Haiku 4.5: 73.3%v
Claude Opus 5.5Claude Opus 5.5: —
SWE-Bench Pro% of tasks resolved · Scale AI SWE-Bench Pro · Sep 22, 2026 · reference
Claude Haiku 4.5Claude Haiku 4.5: —
Terminal-Bench 4.0% of tasks passed · Terminal-Bench · Sep 22, 2026 · reference
Claude Haiku 4.5Claude Haiku 4.5: —

Claude Haiku 4.5Claude Opus 5.5v = reported by the model’s maker. — = no public score yet. Arena bars span the range across every model we grade.

What it costs you

Drag to match your monthly usage.

Claude Haiku 4.5$400 /month
Claude Opus 5.5$1,600 /month

Claude Haiku 4.5 saves you $1,200 a month at this usage, $14,400 a year.

At a glance

AttributeClaude Haiku 4.5Claude Opus 5.5
Made byAnthropicAnthropic
AvailabilityComing soonComing soon
Overall gradeStrong · 57.0Excellent · 99.5
Overall rank#42 of 67#1 of 67
Input price$1.00 per 1M$4.00 per 1M
Output price$5.00 per 1M$20.00 per 1M
Context window200,000 tokens1,000,000 tokens
Reasoning levelsYesYes
Reads imagesYesYes
Model IDclaude-haiku-4-5claude-opus-5-5

Try both with one key

Same endpoint, same key, both hosted in the USA. Change one word to switch models, in Claude Code, Cursor, Cline or your own code.

Get your API key
# Ask either model the same thing
curl https://fullsendai.com/v1/chat/completions \
  -H "Authorization: Bearer $FULLSEND_API_KEY" \
  -d '{"model": "claude-haiku-4-5", "messages": [...]}'

# …then swap one word
  -d '{"model": "claude-opus-5-5", "messages": [...]}'

Questions

Is Claude Haiku 4.5 or Claude Opus 5.5 better?

Claude Opus 5.5 grades 99.5 against 57.0 for Claude Haiku 4.5, from public benchmarks.

Which is cheaper, Claude Haiku 4.5 or Claude Opus 5.5?

Claude Haiku 4.5: $1.00 in and $5.00 out per million tokens, against $4.00 and $20.00 through FullsendAI.

Which has the larger context window?

Claude Opus 5.5, with 1,000,000 tokens.

Can I use both with one API key?

Yes, once they launch: both are coming soon, at the prices shown, and both will use the same FullsendAI key.

Model rankingsAll benchmarksCompare other models

Scores: LMArena (CC BY 4.0), SWE-bench, Scale AI SWE-Bench Pro, Terminal-Bench, and model makers’ published results where marked v. Prices are FullsendAI’s, per million tokens. Data as of Oct 28, 2026.