Updated March 2026
Claude vs OpenAI: Which API Costs Less?
An honest, tier-by-tier comparison of Claude and OpenAI API pricing. OpenAI is cheaper per token at most tiers. Claude offers deeper caching discounts and longer context. Your best choice depends on the workload.
All Models Compared
Prices per million tokens. The cheapest option in each tier is highlighted.
| Provider | Model | Input/MTok | Output/MTok | Context |
|---|---|---|---|---|
| Anthropic | Claude Opus 4 | $15.00 | $75.00 | 200K |
| OpenAI | o1 | $15.00 | $60.00 | 200K |
| OpenAI | o3-mini | $1.10 | $4.40 | 200K |
| Anthropic | Claude Sonnet 4 | $3.00 | $15.00 | 200K |
| OpenAI | GPT-4o | $2.50 | $10.00 | 128K |
| Anthropic | Claude Haiku 3.5 | $0.80 | $4.00 | 200K |
| OpenAI | GPT-4o-mini | $0.15 | $0.60 | 128K |
Tier-by-Tier Analysis
Opus 4 vs o1
Claude Opus 4
$15.00 / $75.00
input / output per MTok
OpenAI o1
$15.00 / $60.00
input / output per MTok
Input pricing is identical at $15/MTok. However, o1 is 20% cheaper on output ($60 vs $75 per MTok). For output-heavy tasks like research reports, o1 has a clear cost advantage. Where Opus 4 justifies its premium is in agentic coding workflows: Claude Code (powered by Opus) is the leading autonomous coding tool, and the quality difference reduces retries and manual intervention. For pure reasoning benchmarks, o1 was purpose-built for chain-of-thought and often outperforms on math and science tasks.
Opus 4 vs o1 vs o3-mini
For tasks that require extended reasoning (multi-step math, formal logic, scientific analysis), OpenAI offers a dedicated reasoning family. The o3-mini model at $1.10/$4.40 per MTok provides surprisingly strong reasoning capability at a fraction of the cost of either Opus or o1. If your use case is primarily reasoning and you can tolerate slightly lower general capability, o3-mini is dramatically cheaper than Opus 4 (93% less on input, 94% less on output).
Claude does not yet have a dedicated reasoning-only model at a budget price point. For reasoning-heavy workloads where cost is the primary concern, OpenAI has a clear advantage with the o1/o3-mini family.
Sonnet 4 vs GPT-4o
Claude Sonnet 4
$3.00 / $15.00
GPT-4o
$2.50 / $10.00
GPT-4o is cheaper: 17% less on input ($2.50 vs $3.00) and 33% less on output ($10 vs $15). For a standard 1K input / 500 output request, GPT-4o costs $0.0075 versus Sonnet's $0.0105 — a 29% saving. At 10,000 requests/month, that is $75 versus $105. Both models are excellent general-purpose options. Sonnet 4 is generally preferred for coding tasks and nuanced writing, while GPT-4o is a strong all-rounder at a lower price.
Haiku 3.5 vs GPT-4o-mini
Claude Haiku 3.5
$0.80 / $4.00
GPT-4o-mini
$0.15 / $0.60
This is where the gap is largest. GPT-4o-mini is 81% cheaper on input and 85% cheaper on output than Haiku 3.5. For high-volume simple tasks (classification, routing, simple Q&A), GPT-4o-mini is the clear cost winner. For 100,000 simple classification requests per month (500 input, 50 output tokens each), GPT-4o-mini costs $10.50 versus Haiku's $60.00. That said, Haiku 3.5 handles edge cases and nuanced instructions better than GPT-4o-mini, so the cheaper model may produce lower accuracy that costs more in downstream corrections.
Same Task, Different Cost
Five common workloads priced on both platforms. Monthly cost at stated volume.
| Task | Claude | OpenAI | Difference |
|---|---|---|---|
| Customer support chatbot2K input + 500 output tokens, 10,000 requests/month | $135.00Sonnet 4 | $100.00GPT-4o | +35% |
| Code review automation4K input + 2K output tokens, 3,000 reviews/month | $126.00Sonnet 4 | $90.00GPT-4o | +40% |
| Bulk email classification500 input + 50 output tokens, 100,000/month | $60.00Haiku 3.5 | $10.50GPT-4o-mini | +471% |
| Research report generation8K input + 4K output tokens, 500 reports/month | $210.00Opus 4 | $180.00o1 | +17% |
| Document summarisation16K input + 1K output tokens, 5,000 docs/month | $315.00Sonnet 4 | $250.00GPT-4o | +26% |
Costs calculated at standard pricing without prompt caching or batch discounts.
Beyond Token Pricing
Per-token price is important, but it is not the only factor. Output quality, context window size, cost-saving features, and ecosystem all affect your total cost of ownership.
Context window
Claude: 200K tokens across all models. OpenAI: 128K for GPT-4o/mini, 200K for o1. Claude's longer default context is useful for processing very long documents without chunking.
Prompt caching
Claude: 90% discount on cached input tokens (10% of standard price). OpenAI: 50% discount on cached input. Claude's caching is nearly twice as aggressive, which makes a real difference for chatbots and RAG workloads with large system prompts.
Batch API
Both providers offer 50% discounts for batch (async) processing. Claude processes batches within 24 hours. OpenAI's batch system is similar. This is a draw — both deliver the same discount.
Output quality
Quality is harder to measure than price, but it affects effective cost. A model that produces correct output on the first try is cheaper than a less accurate model that requires retries. Claude is generally preferred for coding and nuanced writing. OpenAI's o1 excels at structured reasoning.
Rate limits
Both providers use tiered rate limits that increase with spending. OpenAI generally offers higher initial limits. Both offer custom limits for enterprise customers. Check the specific tier limits before committing to high-volume workloads.
Ecosystem
OpenAI has a larger ecosystem: Azure OpenAI Service, Assistants API, fine-tuning, built-in function calling, DALL-E, and Whisper. Anthropic's ecosystem is growing (tool use, computer use, MCP) but is more focused. For enterprises already on Azure, OpenAI integrates more naturally.
The Honest Verdict
Where Claude wins
- +Code generation quality (Sonnet 4 and Opus 4 produce cleaner code)
- +Agentic coding (Claude Code is the leading autonomous coding tool)
- +Prompt caching depth (90% vs OpenAI's 50% cached input discount)
- +200K context across all models (GPT-4o is only 128K)
- +Nuanced, human-sounding writing quality
Where OpenAI wins
- +Lower per-token prices at every tier (17-85% cheaper)
- +GPT-4o-mini is dramatically cheaper for high-volume simple tasks
- +o3-mini provides strong reasoning at a budget price
- +Larger ecosystem (Azure, fine-tuning, Assistants, DALL-E, Whisper)
- +More model variety for specialised use cases
Where it depends
- ?High-volume classification: GPT-4o-mini is cheaper per token, but if Haiku's higher accuracy means fewer errors, the effective cost may be similar.
- ?Cacheable workloads: Claude's 90% caching discount can make Sonnet cheaper than GPT-4o when 60%+ of input is cacheable.
- ?Enterprise integration: If you are already on Azure, OpenAI is the natural choice. If you prioritise safety and constitutional AI, Anthropic is the leader.
Our recommendation: Most production systems benefit from using both providers. Use Claude for coding, complex analysis, and tasks requiring nuanced responses. Use OpenAI (GPT-4o-mini or o3-mini) for high-volume simple tasks where per-token cost dominates. Having both as fallbacks also provides resilience against outages.