Claude Opus 4.8 vs GPT-5.5 Instant
Benchmarks, API Token Pricing, Context Window & Speed Comparison
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Claude Opus 4.8 by Anthropic and GPT-5.5 Instant by OpenAI represent two of the frontier AI models analyzed in our comprehensive 2026 AI benchmark and LLM comparison. In this head-to-head evaluation, we examine API token pricing, context window specifications, inference speed (tokens per second), and empirical reasoning performance. From a pure economic perspective, GPT-5.5 Instant holds a notable pricing advantage for token ingestion. On output generation, GPT-5.5 Instant is more economical per million generated tokens. In data-heavy architectures requiring extensive repository or document analysis, Claude Opus 4.8 provides an expanded memory horizon with 1,000K tokens. In latency-sensitive production environments, GPT-5.5 Instant leads in tokens-per-second throughput, making it ideal for real-time conversational agents and high-concurrency workflows. Below is the complete empirical head-to-head breakdown across cost, speed, context, and capability matrices.
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Claude Opus 4.8
Premium FlagshipThe definitive peak of the Claude 4 generation, integrating dynamic cognitive reasoning depth, a 1M token context, and optional Fast inference modes.
$5.00 / 1M
$25.00 / 1M
1M tokens
80.8%
GPT-5.5 Instant
Low-Latency 5.5A compact GPT for low-latency assistance and high-volume workloads.
$0.75 / 1M
$6.00 / 1M
400K tokens
74.5%
Key Differences at a Glance
- GPT-5.5 Instant is 4.6x cheaper for API usage (input + output tokens combined).
- Claude Opus 4.8 has a larger context window (1M vs 400K tokens).
- GPT-5.5 Instant is faster at 168 tok/s vs 64 tok/s.
- Claude Opus 4.8 leads on SWE-bench coding (80.8% vs 74.5%).
| Feature | Claude Opus 4.8 | GPT-5.5 Instant |
|---|---|---|
Intelligence Index Composite reasoning & knowledge score (0-100) | 67 | 65 |
Provider | Anthropic | OpenAI |
Input Price Cost per million input tokens | $5.00 / 1M | $0.75 / 1M |
Output Price Cost per million output tokens | $25.00 / 1M | $6.00 / 1M |
Blended Price Weighted 7:2:1 cache:input:output per 1M | $3.85 / 1M | $0.80 / 1M |
Context Window Maximum input + output tokens | 1M tokens~1,500 A4 pages of text | 400K tokens~600 A4 pages of text |
Max Output Tokens Per single request | 128K | 128K |
Throughput Speed Tokens generated per second | 64 tok/s | 168 tok/s |
SWE-bench Verified Real-world software engineering | 80.8% | 74.5% |
GPQA Diamond Graduate-level reasoning | 78.9% | 75% |
Cached Input Price Prompt caching discount per 1M tokens | $0.50 / 1M | $0.07 / 1M |
Who Wins Where?
At-a-glance decision frameworkEmpirical Head-to-Head Benchmark Scores
Official evaluation metrics verified by independent third-party research labs.
Industry benchmark evaluating real-world GitHub issue resolution and multi-file debugging.
Challenging questions created by domain experts to test complex PhD-level reasoning.
Hardened reasoning and academic knowledge benchmark with reduced lucky-guess probability.
Crowdsourced human preference evaluation based on blind, head-to-head model battles.
Extremely difficult, closed-ended questions spanning the frontier of human expert knowledge.
Autonomous multi-step tasks executed inside a real command-line terminal environment.
Research-grade coding problems drawn from real scientific and numerical workloads.
Contamination-free competitive programming problems collected continuously over time.
American Invitational Mathematics Examination — multi-step Olympiad-level reasoning.
Accuracy when reasoning over very large inputs that fill the model context window.
Tokens emitted per second during active generation streaming.
Latency & Response Time
Time to first token (TTFT) and estimated end-to-end response time for a typical 500-token response.
Real-Time Interactive Token Cost Simulator
Adjust sliders to calculate projected monthly cloud API spending with prompt caching discounts.
Claude Opus 4.8 · Strengths & Key Advantages
- Peak benchmark performance of the Claude 4 series across all reasoning and math metrics
- Introduced Fast inference tier reducing TTFT on standard conversational turns
- Unmatched multi-step autonomous planning for complex agent swarms
Considerations & Trade-offs
- Expensive output token generation for high-volume non-critical workflows
- Significant hardware resource requirements during peak thinking effort
GPT-5.5 Instant · Strengths & Key Advantages
- Low latency for interactive agents
- Good capability for the price band
- Noticeably lower latency than the full GPT-5.5 tier
Considerations & Trade-offs
- Shallower reasoning than full GPT-5.5
- Struggles with very long multi-step plans
Token Use & Task Economics
Estimated cost and token consumption to complete one representative agentic task.
| Metric | Claude Opus 4.8 | GPT-5.5 Instant |
|---|---|---|
Cost per Task Estimated USD to finish one task | $5.49 | $0.95 |
Output Tokens / Task Tokens generated per task | 72K | 52K |
Reasoning Tokens / Task Thinking tokens burned per task | 37K | 26K |
Technical Specifications
Architecture, release timeline, capabilities, and modalities.
| Feature | Claude Opus 4.8 | GPT-5.5 Instant |
|---|---|---|
| Official API Model ID (SDK) | claude-opus-4-8-20260501 | gpt-5-5-instant |
| API Protocol | Anthropic Messages API + AWS Bedrock + Vertex AI | OpenAI Responses API & Chat Completions v1 |
| Release Date | 2026-05 | 2026-05 |
| Knowledge Cutoff | March 2026 | December 2025 |
| Architecture | Frontier Hybrid Cognitive Architecture | Low-latency compact reasoning model |
| Parameters | Confidential | Confidential |
| Enterprise Rate Limits (RPM / TPM) | 4,000 – 10,000 RPM (Tier 4 + Priority Tier) · 4,000,000 – 10,000,000 TPM | 10,000 – 30,000 RPM (Tier 5 Enterprise) · 800,000 – 2,000,000 TPM |
| Long-Context Tier (>128K/200K) | Standard rate up to 200K tokens; 2x input/output tier above 200K tokens | Flat rate ($0.75/1M in) across full 400K window |
| Prompt Cache Policy & TTL | $0.5/1M cached read (90% off); 5-min default & 1-hour extended TTL | Automatic prefix caching at $0.075/1M (no extra cache-write fee) |
| Computer Use / GUI Agent | Supported (Screen coordinate grounding, browser & desktop GUI action loops) | Supported (Screen coordinate grounding, browser & desktop GUI action loops) |
| MCP & Parallel Tool Calling | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema | Native MCP Client/Server ready · Parallel function calling · 100% Strict JSON Schema |
| Web Search Grounding & Sandbox | Native Web Search Citations + Code Execution Tool + MCP Connectors | Native Web Search tool + Hosted Code Interpreter & File Search RAG |
| Official Fine-Tuning Support | Custom Model Tuning via Amazon Bedrock & Prompt Distillation | Supervised Fine-Tuning (SFT), Direct Preference (DPO) & Reinforcement Fine-Tuning (RFT) |
| Multimodal Token Billing | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) | Text BPE (~4 chars/token) · Vision (~258–765 tokens per image tile) |
| Quantization & Min GPU VRAM | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) | Cloud-Hosted Proprietary (FP8 / BF16 Tensor Core Cluster) · Zero Local VRAM Required (100% Serverless Cloud API) |
| Safety & Frontier Classification | Anthropic RSP ASL-2 / ASL-3 Constitutional Safety Evaluated | OpenAI Preparedness Framework Audited & System Card Published |
| Enterprise Compliance (ZDR/HIPAA/SOC2) | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier | SOC2 Type II · GDPR · Zero Data Retention (ZDR) & HIPAA BAA Available on Enterprise Tier |
| Input Modalities | text, vision | text, vision |
| Output Modalities | text | text |
Claude Opus 4.8 vs GPT-5.5 Instant: Quick Answers
Which is more intelligent, Claude Opus 4.8 or GPT-5.5 Instant?
Claude Opus 4.8 is more intelligent. It scores 67 compared with 65 on the composite Intelligence Index.
Which model is faster?
GPT-5.5 Instant is faster, generating 168 tokens per second compared with 64 tokens per second.
Which model is cheaper to run?
GPT-5.5 Instant is cheaper at $0.80 per 1M tokens blended, compared with $3.85 (7:2:1 cache:input:output ratio).
Which model has lower latency?
GPT-5.5 Instant has lower latency, with a time to first token of 0.78s compared with 1.65s.
Which model has a larger context window?
Claude Opus 4.8 has a larger context window, supporting 1M tokens compared with 400K tokens.
Verdict
Verdict & Model Selection Recommendation: Choose Claude Opus 4.8 if your priority is Frontier AI research, multi-agent systems orchestration, and enterprise software engineering. Its performance in demanding tasks justifies its operational token cost. Choose GPT-5.5 Instant if your workflow prioritizes Interactive assistants and latency-sensitive routing. For large-scale batch processing or customer-facing conversational interfaces, its balance of speed and economics delivers superior ROI.
Frequently asked questions
How does Claude Opus 4.8 compare to GPT-5.5 Instant in API token pricing and cost per token?+
Claude Opus 4.8 costs $5.00 per 1M input tokens and $25.00 per 1M output tokens, whereas GPT-5.5 Instant costs $0.75 input and $6.00 output. Overall, GPT-5.5 Instant is the more cost-effective model for high-volume API pipelines. Both models support prompt caching discounts of up to 90% for repeated prompt prefixes.
Which model has a larger context window: Claude Opus 4.8 or GPT-5.5 Instant?+
Claude Opus 4.8 supports a context window of 1,000K tokens (~750k words), while GPT-5.5 Instant supports 400K tokens (~300k words). Therefore, Claude Opus 4.8 can process more textual data and document context in a single prompt.
Which AI model is better for software engineering and coding: Claude Opus 4.8 or GPT-5.5 Instant?+
Claude Opus 4.8 scores 80.8% on SWE-bench Verified while GPT-5.5 Instant scores 74.5%. For autonomous software engineering and multi-file debugging, Claude Opus 4.8 holds the verified benchmark lead.
What is the difference in reasoning capability and extended thinking between Claude Opus 4.8 and GPT-5.5 Instant?+
Claude Opus 4.8 features native chain-of-thought extended thinking mode with configurable reasoning effort. In contrast, GPT-5.5 Instant provides chain-of-thought reasoning depth for complex math and science.
How does inference speed (tokens per second) compare between Claude Opus 4.8 and GPT-5.5 Instant?+
Claude Opus 4.8 generates approximately 64 tokens per second, while GPT-5.5 Instant delivers 168 tokens per second. In latency-sensitive production environments, GPT-5.5 Instant provides faster time-to-first-token (TTFT) and higher streaming response velocity.
Can you implement a tiered LLM routing setup combining Claude Opus 4.8 and GPT-5.5 Instant to optimize costs?+
Yes! High-efficiency architectures route high-frequency routine classification and conversational tasks to GPT-5.5 Instant to save operational costs, and dynamically escalate complex architectural queries or reasoning tasks to Claude Opus 4.8. This tiered routing pattern cuts overall API bills by up to 70%.
Understand key metrics like context window, token pricing, reasoning mode, and SWE-bench scores in our comprehensive AI glossary.
Related reading
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Benchmark scores, token prices, and rate limits evolve rapidly as AI labs release model updates. Always verify current specifications and pricing on the official provider documentation.
Sources: GetInfoUs Independent AI Benchmarks & Official API Specs