Claude Haiku 5.5 vs Haiku 4.5
Haiku 5.5 lists at $0.10 per million input tokens against $1.00 for Haiku 4.5, and its tokenizer counts about 30% more tokens for the same text.
Yes, upgrading from Claude Haiku 4.5 to Claude Haiku 5.5 is worth the migration for most high-volume business workflows. Claude Haiku 5.5 lists at one-tenth of Claude Haiku 4.5 input pricing ($0.10 compared to $1.00 per million tokens) and scores higher on every benchmark where Anthropic reports both models. The main operational catch sits in the newer tokenizer, which counts roughly 30 percent more tokens for identical text strings, so test your real bill.
At Layer3Labs, we build and run AI systems inside other people's businesses.
Anthropic released Claude Haiku 5.5 on October 7, 2026, marking it active, with retirement not sooner than October 7, 2027. The pages we checked give no retirement date for Haiku 4.5.
Claude Haiku 5.5 vs. Claude Haiku 4.5: Side-by-Side
| Dimension | Claude Haiku 5.5 | Claude Haiku 4.5 |
|---|---|---|
| Release date | October 7, 2026 | Not published |
| Model ID | claude-haiku-5-5 (Bedrock: anthropic.claude-haiku-5-5) | Not published |
| Input price (prompts up to 100K tokens) | $0.10 per million tokens | $1.00 per million tokens |
| Output price (prompts up to 100K tokens) | $0.50 per million tokens | $5.00 per million tokens |
| Cache read price | $0.01 per million tokens (prompts up to 100K) | $0.10 per million tokens |
| Cache write price | $0.125 per million tokens (5-minute; prompts up to 100K) | $1.25 per million tokens |
| Context window | 1,000,000 tokens (1M) | Not published |
| Maximum output tokens | 128,000 tokens (128K; 300K in beta on Batch API) | Not published |
| Effort setting | Yes (low, medium, high, xhigh, max; default medium) | No (first Haiku-class model with an adjustable effort setting) |
| Tokenizer | Newer tokenizer (counts about 30% more tokens) | Not published |
| GDPval-AA v2.1 | 1620 Elo | 735 Elo |
| AA-Briefcase v1.1 | 1578 | 614 |
| OSWorld 2.1 (offline subset) | 72.4% | 15.7% |
| Humanity's Last Exam (no tools) | 45.9% | 10.2% |
| Humanity's Last Exam (with tools) | 57.4% | 18.7% |
| Terminal-Bench 4.0 | 39.2% | 0.0% |
| Chartography (no tools) | 46.4% | 6.4% |
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Should You Upgrade From Haiku 4.5?
Haiku 5.5 lists at $0.10 per million input tokens against $1.00 for Haiku 4.5, but its tokenizer counts about 30% more tokens for the same text. Anthropic designed Haiku 5.5 specifically for cost-sensitive operations, text compactions, live customer support, and browser interactions. It also serves as a high-speed subagent pairing with Opus 5.5 or Sonnet 5.5 on complex development work.
Security teams conducting automated penetration testing should not upgrade to Haiku 5.5. Anthropic added more restrictive cybersecurity safeguards to Haiku 5.5 that block penetration testing. Haiku 4.5's cybersecurity safeguards are less restrictive, per Anthropic.
Above 100,000 tokens, Haiku 5.5 input costs $0.50 per MTok, and the tokenizer adds tokens on top, so the saving is smaller there. For standard prompts under 100,000 tokens, Haiku 5.5 is cheaper.
- Core tasks suited for upgrade: summaries, text compactions, database queries, classification, extraction, and routing.
- Agentic tasks suited for upgrade: live customer support, browser execution, and sidekick subagent coding.
- Who should stay on Haiku 4.5: penetration testers whose prompt suites trigger Haiku 5.5's stricter security filters.
Price Difference and Tokenizer Arithmetic
Claude Haiku 5.5 lowers baseline input pricing by 90 percent and output pricing by 90 percent for standard prompts up to 100,000 tokens. On standard calls, Haiku 5.5 charges $0.10 per million tokens (MTok) for input and $0.50 per MTok for output, compared to $1.00 input and $5.00 output on Claude Haiku 4.5. Prompts up to 100,000 tokens account for roughly 90 percent of requests sent to the previous Haiku model, according to Anthropic.
When prompt context exceeds 100,000 tokens, Haiku 5.5 pricing shifts to a higher tier: $0.50 per MTok for input and $2.50 per MTok for output. Cache reads cost $0.01 per MTok on standard prompts (jumping to $0.05 over 100,000 tokens), whereas Haiku 4.5 cache reads cost $0.10 per MTok. A 5-minute cache write on Haiku 5.5 costs $0.125 per MTok ($0.625 over 100,000 tokens) and a 1-hour write costs $0.20 per MTok ($1.00 over 100,000 tokens), compared to $1.25 per MTok for Haiku 4.5 cache writes.
The financial calculation must account for the newer tokenizer. Haiku 5.5 uses the same tokenizer as Claude 4.7 and later, so the same text counts as about 30 percent more tokens than Haiku 4.5 for the same text. For illustration, a prompt that measured 1,000,000 tokens under Haiku 4.5 cost $1.00. That same text measures approximately 1,300,000 tokens under Haiku 5.5. At the $0.10 base rate, processing those 1.3 million tokens across multiple sub-100K calls costs $0.13, yielding an effective 87 percent reduction in input expense. Anthropic states that overall operating costs drop around 75 percent on average.
Capability Difference Across Published Benchmarks
Anthropic published comparative benchmark tables demonstrating that Claude Haiku 5.5 outperforms Claude Haiku 4.5 on every benchmark where both scores are reported. On GDPval-AA v2.1, Haiku 5.5 scored 1620 Elo compared to 735 Elo for Haiku 4.5, and scored 1578 on AA-Briefcase v1.1 compared to 614 for Haiku 4.5. On OSWorld 2.1, Haiku 5.5 achieved 72.4 percent on the OSWorld 2.1 offline subset, while Haiku 4.5 reached 15.7 percent.
On Humanity's Last Exam (HLE) without tools, Haiku 5.5 scored 45.9 percent against 10.2 percent for Haiku 4.5, rising to 57.4 percent with tools against 18.7 percent for Haiku 4.5. On Terminal-Bench 4.0, Haiku 5.5 recorded 39.2 percent while Haiku 4.5 scored 0.0 percent. On Chartography without tools, Haiku 5.5 recorded 46.4 percent compared to 6.4 percent for Haiku 4.5. On FrontierCode 1.1 Main, Haiku 5.5 scored 46.4 percent, while Anthropic did not report a score for Haiku 4.5.
Anthropic quotes these customer reports. Asana documented over 30 percent lower latency and up to 2.5 times faster inference per agent turn. HubSpot scored 92.8 percent across a three-run average on its CRM task suite. Box scored 11 points higher than Haiku 4.5 while roughly halving latency, and AlphaSense recorded a 0.84 score versus 0.76 for Haiku 4.5 across 400 queries on Ask in Document (about 8M calls a week).
- GDPval-AA v2.1: 1620 Elo for Haiku 5.5 versus 735 Elo for Haiku 4.5.
- OSWorld 2.1 offline subset: 72.4 percent for Haiku 5.5 versus 15.7 percent for Haiku 4.5.
- Terminal-Bench 4.0: 39.2 percent for Haiku 5.5 versus 0.0 percent for Haiku 4.5.
- Cognition reported a 66.2 FrontierCode score for Devin Fusion using Haiku 5.5 as sidekick and Opus 5.5 as lead.
Context Windows, Effort Settings, and Safeguards
Claude Haiku 5.5 expands context capacity to 1,000,000 tokens, compared to Haiku 4.5 whose context limit was not published on the documentation pages we checked. Maximum generation length on Haiku 5.5 reaches 128,000 tokens, with a 300,000-token output limit available in beta through the Batch API. The knowledge cutoff date for Haiku 5.5 is June 2026.
Haiku 5.5 is the first Haiku-class model to incorporate an adjustable effort parameter. Adaptive thinking operates by default at medium effort, but developers can configure effort to low, medium, high, xhigh, or max. Thinking blocks work only in the account that produced them or a linked account.
Anthropic reports substantial alignment improvements over Haiku 4.5. Biological risk safeguards on Haiku 5.5 match the safety standards of Sonnet 5, Sonnet 5.5, and Opus 5. Cybersecurity safeguards are stricter than those on Haiku 4.5 and actively block penetration testing requests. Deployment is supported across the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry, and Claude Platform on AWS.
Migration Checks for Production Deployments
Migrating production workloads from Claude Haiku 4.5 to Claude Haiku 5.5 requires updating API model strings and re-evaluating prompt token counts. The model identifier is claude-haiku-5-5 for direct API calls, and anthropic.claude-haiku-5-5 for Amazon Bedrock deployments. Anthropic mentions a formal migration guide in the Claude platform documentation.
Because the tokenizer produces roughly 30 percent more tokens for identical strings, run a sample batch of your actual prompts through the newer tokenizer before updating your production spend alerts. If your workflows pass stored thinking blocks across accounts, note that thinking blocks work only in the account that produced them, or a linked account.
Audit existing prompts against the updated guardrails. If your application tests security configurations or uses adversarial system prompts, confirm that Haiku 5.5 does not trigger policy refusals where Haiku 4.5 passed.
- Update the target model string to claude-haiku-5-5 or anthropic.claude-haiku-5-5.
- Recalculate token allowances across billing dashboards to accommodate the 30 percent tokenizer expansion.
- Check the effort setting (default medium).
- Audit any penetration testing prompts to confirm they do not trigger Haiku 5.5's stricter security filters.
Where Haiku 5.5 Falls Short of Sonnet 5.5
Claude Sonnet 5.5 maintains a performance advantage over Claude Haiku 5.5 on every complex evaluation listed by Anthropic. Sonnet 5.5 costs $2.00 per MTok for input and $10.00 per MTok for output, representing twenty times the base input rate of Haiku 5.5. Anthropic also halved Sonnet 5.5 cache-read pricing to $0.10 per MTok, which lowers agentic operational costs by about 20 percent.
On GDPval-AA v2.1, Sonnet 5.5 scores 1840 Elo compared to 1620 Elo for Haiku 5.5. On AA-Briefcase v1.1, Sonnet 5.5 scores 1824 against 1578. The capability spread widens on technical work: Sonnet 5.5 scores 83.9 percent on OSWorld 2.1 versus 72.4 percent for Haiku 5.5, and 70.6 percent on Terminal-Bench 4.0 versus 39.2 percent for Haiku 5.5. On Chartography without tools, Sonnet 5.5 reaches 61.6 percent compared to 46.4 percent for Haiku 5.5.
Teams requiring higher benchmark performance should retain Sonnet 5.5. Run test prompts through Claude Haiku 5.5 on your own prompts to evaluate accuracy and token expansion before rerouting production traffic from Claude Haiku 4.5.
The Verdict
Upgrade to Claude Haiku 5.5 if your workload centers on high-volume extraction, summarization, classification, or subagent tasks.
The 90 percent reduction in base input pricing combined with superior benchmark scores across every published category makes Haiku 5.5 an immediate upgrade over Haiku 4.5 after re-counting tokens on your real prompts.
Retain Haiku 4.5 only if your team conducts cybersecurity penetration testing blocked by Haiku 5.5's stricter guardrails.
Researched from primary vendor documentation and public regulator sources. Pricing and availability are accurate as of Oct 8, 2026 and can change — confirm current terms with each vendor before you buy.
Frequently Asked Questions
- Yes. For prompts up to 100,000 tokens, Claude Haiku 5.5 costs $0.10 per million input tokens and $0.50 per million output tokens, compared to $1.00 and $5.00 on Claude Haiku 4.5. Anthropic says it costs around 75 percent less to run on average than Haiku 4.5. The new tokenizer counts about 30% more tokens for the same text, so test your real bill.
- Yes. Claude Haiku 5.5 scores higher on every benchmark where Anthropic reports both models. It scores 1620 Elo versus 735 Elo on GDPval-AA v2.1, 72.4 percent versus 15.7 percent on OSWorld 2.1, and 39.2 percent versus 0.0 percent on Terminal-Bench 4.0.
- Yes. You must update your API calls to target the model identifier claude-haiku-5-5, or anthropic.claude-haiku-5-5 on Amazon Bedrock. You should also evaluate the effort setting, which defaults to medium, and verify that any shared thinking blocks remain within the originating or linked account.
- Claude Haiku 5.5 uses the same newer tokenizer as Claude 4.7 and later, so the same text counts as about 30% more tokens than on Haiku 4.5.
- Choose Claude Sonnet 5.5 if your tasks require higher benchmark performance. Sonnet 5.5 costs $2.00 per million input tokens and $10.00 per million output tokens, but it scores higher across all published benchmarks, including 70.6 percent on Terminal-Bench 4.0 compared to 39.2 percent for Haiku 5.5.
- Anthropic lists Haiku 5.5's retirement as not sooner than October 7, 2027. The pages we checked give no retirement date for Haiku 4.5.
Planning a Claude Model Migration?
At Layer3Labs, we build and run AI systems inside other people's businesses. We build custom agents and integrations that work over your business's own documents.
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