Anthropic Claude Opus 4.6 vs OpenAI GPT 4o (2024-05-13)
Anthropic Claude Opus 4.6 (OpenRouter, 1,000,000-token context) versus OpenAI GPT 4o (2024-05-13) (OpenRouter, 128,000-token context). OpenAI GPT 4o (2024-05-13) is cheaper by 33% on a blended token mix. Anthropic Claude Opus 4.6 uniquely supports prompt caching and native reasoning mode. OpenAI GPT 4o (2024-05-13) uniquely supports parallel tool calls. Use the live calculator below to plug your real usage shape into both, then route the winner via Agent Command Center for shadow A/B without code changes.
Bottom line — Anthropic Claude Opus 4.6 vs OpenAI GPT 4o (2024-05-13)
Anthropic Claude Opus 4.6 and OpenAI GPT 4o (2024-05-13) target overlapping workloads but differ sharply on economics. OpenAI GPT 4o (2024-05-13) runs roughly 33% cheaper on a blended input-plus-output token mix, which translates to approximately $6,000 per month at mid-market volume (100K requests/day). The gap compounds at enterprise scale, making the cost axis the first filter most teams apply when deciding between these two models.
Anthropic Claude Opus 4.6 ships a 1,000,000-token context window, 7.8x larger than OpenAI GPT 4o (2024-05-13)'s 128,000 tokens. That headroom matters for long-document RAG pipelines, multi-turn agent sessions that accumulate tool-call history, and codebases where the entire repository needs to fit in a single prompt. If your average prompt stays under 128,000 tokens, the extra context on Anthropic Claude Opus 4.6 is insurance you may never use — and OpenAI GPT 4o (2024-05-13) may win on other axes.
On capability surface area, the models diverge: Anthropic Claude Opus 4.6 supports prompt caching where the other does not; Anthropic Claude Opus 4.6 supports native reasoning mode where the other does not; OpenAI GPT 4o (2024-05-13) supports parallel tool calls where the other does not. These differences are binary — either your workload needs the capability or it does not. Check whether any critical path in your agent pipeline depends on a capability only one model provides before committing to a migration.
For teams evaluating both models, the recommended path is a shadow A/B test: route production traffic through an OpenAI-compatible gateway, mirror a percentage to the candidate model, score both responses with an automated evaluator (faithfulness, tool-call correctness, latency), and compare cohort-level metrics over two weeks. Future AGI Agent Command Center supports this pattern with a single `base_url` change and built-in evaluators from the ai-evaluation SDK.
Live workload comparison
Same workload run through both models. The cheaper one is highlighted.
strategy: cost-optimized
primary:
model: openai-gpt-4o-2024-05-13
provider: openrouter
fallback:
model: anthropic-claude-opus-4-6
provider: openrouter
shadow: { sample_rate: 0.05 } # mirror 5% of traffic to compare quality live| Anthropic Claude Opus 4.6 | OpenAI GPT 4o (2024-05-13) | |
|---|---|---|
| Input price | $5.00/M | $5.00/M |
| Output price | $25.00/M | $15.00/M |
| Context window | 1,000,000 | 128,000 |
| Max output | 128,000 | 4,096 |
| Function calling | ✓ | ✓ |
| Vision | ✓ | ✓ |
| Audio input | — | — |
| Reasoning | ✓ | — |
| Prompt caching | ✓ | — |
| Structured output | — | — |
| Pricing verified | Aug 6, 2026 | Aug 6, 2026 |
Cost at scale: monthly spend at three usage volumes
Estimated monthly cost assuming 1,000 input + 200 output tokens per request — a realistic chat-agent shape. Adjust your own usage in the calculator at the top of this page for an exact number.
| Scale | Anthropic Claude Opus 4.6 | OpenAI GPT 4o (2024-05-13) | Delta |
|---|---|---|---|
| Startup 10K requests/day | $3,000 /mo | $2,400 /mo | $600/mo |
| Mid-market 100K requests/day | $30,000 /mo | $24,000 /mo | $6,000/mo |
| Enterprise 1M requests/day | $300,000 /mo | $240,000 /mo | $60,000/mo |
At enterprise scale (1M requests/day), a difference of even ~10% in unit price compounds into thousands of dollars per month. Cached input pricing and batch tiers can shift this further — both are surfaced on each model's own page.
When to choose which
Picked from the data above — not vendor marketing. Match the rules to your workload, not the other way around.
You're cost-sensitive at scale — OpenAI GPT 4o (2024-05-13) runs ~33% cheaper on a blended in+out token mix, compounding into thousands of dollars per month at production volume.
Your workload needs long context — Anthropic Claude Opus 4.6 fits 1,000,000 tokens versus the other model's 128,000, enough headroom for full books, large codebases, or 100+ page documents in one shot.
Your tasks involve multi-step planning or math-heavy reasoning — Anthropic Claude Opus 4.6 ships a native reasoning mode that explicitly thinks before responding, the other doesn't.
You re-send the same large system prompt across requests — Anthropic Claude Opus 4.6 supports prompt caching, cutting input cost on repeat hits.
Capability diff — what you gain and lose on the swap
A specific list of what each model has that the other doesn't. If your workload depends on a row in Only Anthropic Claude Opus 4.6, switching to OpenAI GPT 4o (2024-05-13) means re-architecting that path (and vice versa).
- • Prompt caching
- • Native reasoning mode
- • Parallel tool calls
Capabilities both share (3)
- ✓ Function calling
- ✓ Vision input
- ✓ Streaming
Migration considerations
Concrete differences to wire through your stack before you flip traffic from one to the other.
- Context window changes down 87% when moving from Anthropic Claude Opus 4.6 (1,000,000) to OpenAI GPT 4o (2024-05-13) (128,000). Re-check any prompt that relies on cramming long history or documents.
- Max output tokens differ: 128,000 on Anthropic Claude Opus 4.6 vs 4,096 on OpenAI GPT 4o (2024-05-13). Long-form generation tasks may truncate differently — adjust streaming UI and chunking accordingly.
- Anthropic Claude Opus 4.6 has capabilities OpenAI GPT 4o (2024-05-13) lacks: Prompt caching, Native reasoning mode. Switching to OpenAI GPT 4o (2024-05-13) means re-architecting any flow that depends on these.
- OpenAI GPT 4o (2024-05-13) has capabilities Anthropic Claude Opus 4.6 lacks: Parallel tool calls. Worth wiring through the agent design before commit.
How to A/B test Anthropic Claude Opus 4.6 vs OpenAI GPT 4o (2024-05-13) in production
If you're stuck between the two, run them side-by-side on real traffic. Four steps the Future AGI team uses internally:
- 1. Point your existing OpenAI SDK at
https://gateway.futureagi.com/v1. No code change beyondbase_urland a virtual key. - 2. Mark Anthropic Claude Opus 4.6 primary, mirror 20% of traffic to OpenAI GPT 4o (2024-05-13) in shadow mode. Both responses are logged; only the primary is served to users.
- 3. Score every shadow response with an evaluator — faithfulness, tool-call correctness, response latency, cost. Built-in evaluators in ai-evaluation cover the common axes.
- 4. Compare cohort-level metrics after two weeks. Switch primary when the candidate wins on what matters to your workload — and stays within your latency budget.
Full walkthrough on the Agent Command Center page.
FAQ — Anthropic Claude Opus 4.6 vs OpenAI GPT 4o (2024-05-13)
Which is cheaper, Anthropic Claude Opus 4.6 or OpenAI GPT 4o (2024-05-13)? ▾
OpenAI GPT 4o (2024-05-13) is cheaper by roughly 33% on a blended input + output token mix. Input prices are $5.00/M for Anthropic Claude Opus 4.6 versus $5.00/M for OpenAI GPT 4o (2024-05-13); output prices are $25.00/M versus $15.00/M. The exact savings depend on your input:output ratio — use the live calculator above to plug in your own request shape.
What is the context window of Anthropic Claude Opus 4.6 versus OpenAI GPT 4o (2024-05-13)? ▾
Anthropic Claude Opus 4.6 supports up to 1,000,000 tokens of context. OpenAI GPT 4o (2024-05-13) supports up to 128,000 tokens. Anthropic Claude Opus 4.6 has the larger window by a factor of 7.8x, which matters for long-document RAG, multi-turn agent sessions, and tasks that need to keep an entire codebase in working memory.
Do Anthropic Claude Opus 4.6 and OpenAI GPT 4o (2024-05-13) both support tool calling? ▾
Yes — both Anthropic Claude Opus 4.6 and OpenAI GPT 4o (2024-05-13) support native function calling. Both also support structured output via JSON schema, so an agent can be ported between them with the same tool definitions.
Which model supports prompt caching for cost reduction? ▾
Anthropic Claude Opus 4.6 supports prompt caching; the other does not. If your agent has a stable system prompt + retrieval context block that repeats across requests, Anthropic Claude Opus 4.6 gives you a 50–90% discount on those repeated input tokens at the provider level.
When should I choose Anthropic Claude Opus 4.6 over OpenAI GPT 4o (2024-05-13)? ▾
Your workload needs long context — Anthropic Claude Opus 4.6 fits 1,000,000 tokens versus the other model's 128,000, enough headroom for full books, large codebases, or 100+ page documents in one shot. Your tasks involve multi-step planning or math-heavy reasoning — Anthropic Claude Opus 4.6 ships a native reasoning mode that explicitly thinks before responding, the other doesn't. You re-send the same large system prompt across requests — Anthropic Claude Opus 4.6 supports prompt caching, cutting input cost on repeat hits.
When should I choose OpenAI GPT 4o (2024-05-13) over Anthropic Claude Opus 4.6? ▾
You're cost-sensitive at scale — OpenAI GPT 4o (2024-05-13) runs ~33% cheaper on a blended in+out token mix, compounding into thousands of dollars per month at production volume.
How do I A/B test Anthropic Claude Opus 4.6 against OpenAI GPT 4o (2024-05-13) in production? ▾
Route both through an OpenAI-compatible gateway like Future AGI Agent Command Center with shadow mode enabled. Send 100% of traffic to your primary model, mirror 10–20% to the candidate, score every response with an evaluator (faithfulness, tool-call correctness, response time), and compare cohort-level metrics for two weeks. Switch when the candidate wins on the metrics that matter to your workload and stays within your latency budget.