Skip to content
ModelCap

Head-to-head comparison

Claude Haiku 4.5 vs Claude Sonnet 5.5

Claude Haiku 4.5 (Anthropic) and Claude Sonnet 5.5 (Anthropic) compared on the ModelCap Index, API price, context window, provider availability, weight access and every public benchmark board they share. Figures are the same ones shown on the live rankings; nothing here is a hidden score.

Snapshot as of 3 October 2026

As of 3 October 2026, Claude Sonnet 5.5 holds the stronger ModelCap Index position (#6 vs #78); Claude Haiku 4.5 is 2× cheaper per output token ($5.00/1M vs $10.00/1M); and Claude Sonnet 5.5 offers the longer context window (1M vs 200K tokens).

Which should you choose?

Choose Claude Haiku 4.5 if…

  • API cost matters — $5.00/1M output tokens against $10.00/1M, about 2× cheaper.
  • your workload is prompt-heavy — input tokens cost $1.00/1M against $2.00/1M.

Choose Claude Sonnet 5.5 if…

  • you want the stronger overall ModelCap Index position — #6 against #78 (82.3 vs 58.8 points).
  • you need the longer context window — 1M tokens against 200K.
  • you want provider choice — 5 listed API providers against 4.
  • Arena text is your yardstick — 1471 against 1414.
  • Arena coding is your yardstick — 1536 against 1481.
  • you want the more recently listed model — Claude Sonnet 5.5 was listed 28 September 2026, Claude Haiku 4.5 15 October 2025.

Claude Haiku 4.5 vs Claude Sonnet 5.5: specs, pricing and context

Specification comparison of Claude Haiku 4.5 and Claude Sonnet 5.5
FieldClaude Haiku 4.5AnthropicClaude Sonnet 5.5Anthropic
ModelCap Index position#78#6
Index score58.882.3
EvidenceMeasuredMeasured
Input price / 1M tokens$1.00$2.00
Output price / 1M tokens$5.00$10.00
Context window200K tokens1M tokens
Declared route output cap64K128K
API providers listed45
Weight accessNo linked weightsNo linked weights
Input modalitiesText, Image, FileText, Image, File
First listed15 October 202528 September 2026
PublisherAnthropicAnthropic

Evidence: 3 public benchmark observations across 3 boards · 4 public benchmark observations across 4 boards. Prices are the lowest listed API offer per million tokens observed on the OpenRouter catalogue.

Benchmark scores: Claude Haiku 4.5 vs Claude Sonnet 5.5

Public benchmark boards where Claude Haiku 4.5 or Claude Sonnet 5.5 has a published result
BoardClaude Haiku 4.5Claude Sonnet 5.5Leads
Arena textArena (LMArena)14141411–1416Not reported14711461–1481X-HighClaude Sonnet 5.5
Arena codingArena (LMArena)14811477–148515361515–1558X-HighClaude Sonnet 5.5
LMArena AgentLMArena—12.5%9.4%–15.6%MaxOnly one result
ARC-AGI-2ARC Prize Foundation4.0%Thinking—Only one result
SWE-benchSWE-bench (Princeton / SWE-agent team)66.6%High—Only one result
BFCL V4UC Berkeley (Gorilla)68.7Function calling—Only one result
AA Intelligence IndexArtificial Analysis—56.0ReasoningOnly one result
AA Humanity's Last ExamArtificial Analysis—55.0%Adaptive Reasoning, Max Effort, Default FallbackOnly one result

Scores are the sources' own published figures for each model's best evaluated configuration; ModelCap never re-runs a benchmark.

Want a different pairing? Open the interactive comparison tool to swap either model for any current ranked language model.

Claude Haiku 4.5 vs Claude Sonnet 5.5: common questions

Is Claude Haiku 4.5 better than Claude Sonnet 5.5?

Claude Sonnet 5.5 ranks higher on the ModelCap Index as of 3 October 2026: #6 against #78. That is a capability ranking built from public benchmark evidence with published uncertainty; whether it is "better" for you also depends on price, context and where you can run it. Their published uncertainty intervals do not overlap, but the aggregate Index does not predict performance on every task; compare the relevant benchmark configurations before choosing.

Is Claude Haiku 4.5 cheaper than Claude Sonnet 5.5?

Claude Haiku 4.5 is cheaper on output tokens: $5.00/1M against $10.00/1M. Input tokens are $1.00/1M for Claude Haiku 4.5 and $2.00/1M for Claude Sonnet 5.5. Prices are the lowest listed API offer ModelCap observed, in USD per million tokens. For 1,000 requests with 2,000 input and 500 output tokens each (2M input + 0.5M output), the listed-rate estimate is $4.50 for Claude Haiku 4.5 versus $9.00 for Claude Sonnet 5.5. Claude Haiku 4.5 costs 50.0% less in this scenario. This excludes caching, batch discounts, prompt-length tiers, tool charges and retries; verify the selected endpoint before budgeting.

Which has the bigger context window, Claude Haiku 4.5 or Claude Sonnet 5.5?

Claude Sonnet 5.5 has the larger context window: 1M tokens against 200K. OpenRouter catalogue or provider-endpoint declaration. Limits can vary by provider and prompt length; a model-wide maximum has not been independently verified.

Which is better for coding, Claude Haiku 4.5 or Claude Sonnet 5.5?

Arena coding: Claude Haiku 4.5 1481, Claude Sonnet 5.5 1536 — Claude Sonnet 5.5 leads.

Are Claude Haiku 4.5 and Claude Sonnet 5.5 open-weight models?

Claude Haiku 4.5: No linked weights. Claude Sonnet 5.5: No linked weights. Open weights mean the checkpoint can be downloaded and self-hosted under its licence. A missing weight link does not identify every API or chat product that offers a model.

Where can I run Claude Haiku 4.5 and Claude Sonnet 5.5?

ModelCap currently lists 4 API providers for Claude Haiku 4.5 and 5 for Claude Sonnet 5.5, from the OpenRouter catalogue snapshot the site serves; each model page lists the providers and their prices.

How current is this Claude Haiku 4.5 vs Claude Sonnet 5.5 comparison?

Every figure and ModelCap Index position comes from the same published snapshot dated 3 October 2026. Publication and page updates happen separately; use the snapshot date shown on the page.

Explore further