OpenAI vs Claude API pricing.
Side-by-side for every current model, in the tier each belongs to, with cost-equivalence math on four real workloads. If you're choosing between providers or considering a migration, the decision lives below.
At every tier, OpenAI is cheaper by 10–30%. GPT-4o mini ($0.15/$0.60) is 85% cheaper than Claude Haiku 4.5 ($1/$5) for input-heavy work. GPT-4o ($2.50/$10) undercuts Claude Sonnet 4.6 ($3/$15). Claude Opus 4.7 output costs 25% more than o1 output.
Claude wins on context and often on long-document work. Every Claude model has a 200K-token context window. OpenAI's flagships cap at 128K. For RAG with large chunks, legal/contract analysis, or summarizing books, Claude's context advantage can outweigh the price premium.
Side-by-side, per million tokens
Prices in USD per 1,000,000 tokens. Context is maximum combined input-plus-output window. “O” = OpenAI, “A” = Anthropic.
Where each provider leads
Pricing is only one axis. A cheaper model that can't do what your workload needs is not actually cheaper.
Same workload, both providers
Per-million-token rates are hard to intuit. Monthly dollars on your actual workload are not. Each row below runs the same job on the comparable tier from each provider.
Assumes 30-day months with flat daily request volume. Real workloads are bursty; real bills have spikes. Use the calculator to model your own shape.
Pick OpenAI or Claude based on your workload shape
The real cost of switching
For most production services, migrating between OpenAI and Claude is a 4–8 hour engineering task per service — not a multi-week project. Here's what actually changes:
SDK shape
Anthropic's SDK mirrors OpenAI's on most patterns: messages, streaming, system prompts, tools. Biggest difference: no completions endpoint — everything goes through messages. System prompt is a top-level field, not a message role.
Tool use
Similar concept, slightly different schema. OpenAI calls tool results tool messages; Claude calls them tool_result content blocks. Migration is mechanical — a search-and-replace over your tool-call dispatching code.
Prompt portability
Prompts often transfer with minimal changes. Claude tends to prefer XML-tagged structure (<instructions>...</instructions>) in its system prompts; GPT prefers plain-text delimiters. A well-written GPT prompt will usually work on Claude with minor formatting nudges — but re-evaluate on your test set, because token counts differ between tokenizers.
Evaluation cost
Budget 1–2 days to re-run your eval suite on the new provider. Quality-neutral migrations are common; quality-different migrations happen and need to be caught. Running evals in Batch API mode halves this cost.
Rate limit tier reset
Each provider has its own rate limit tier system. A migration to Claude starts you at tier 1 regardless of your OpenAI usage history. Scale up gradually; tier progression typically takes 1–2 weeks of sustained traffic.
One cap, two providers
If you run both — dual-provider is common for redundancy or workload-specific optimization — your monthly exposure is the sum. The provider dashboards each show only their own bill. You need something that sums them.
Capped reads from OpenAI's /v1/organization/costs endpoint and Anthropic's /v1/organizations/cost_report endpoint in the same sync, aggregates into a single monthly total, and fires one desktop notification at 80%, 100%, and 150% of your combined cap. Read-only admin keys. Keys stay in your browser on the free tier.
Frequently asked
Which is cheaper: OpenAI or Claude API?
It depends on the tier. At the efficient tier, GPT-4o mini ($0.15/$0.60 per million tokens) is the cheapest option on either provider. At the flagship tier, GPT-4o ($2.50/$10) is cheaper than Claude Sonnet 4.6 ($3/$15). At the frontier tier, OpenAI's o1 ($15/$60) is cheaper than Claude Opus 4.7 ($15/$75) because Opus's output rate is 25% higher. For high-output workloads, OpenAI is consistently cheaper at comparable quality tiers.
Is GPT-4o or Claude Sonnet better for general-purpose work?
Both are flagship models with similar capabilities. GPT-4o is cheaper ($2.50/$10 vs $3/$15). Claude Sonnet 4.6 has a 200K-token context window (vs GPT-4o's 128K) and is often preferred for long-document analysis. For cost-sensitive general work, GPT-4o. For long-context work, Claude Sonnet.
What's the cheapest Claude model?
Claude Haiku 4.5, at $1 per million input tokens and $5 per million output tokens. It has a 200K-token context window (larger than GPT-4o mini's 128K) but is more expensive per token. For cost-minimizing workloads, GPT-4o mini at $0.15/$0.60 is still cheaper.
How does Claude Opus compare to OpenAI o1?
Both are frontier reasoning models at the top of each provider's pricing. o1 is $15/$60 per million tokens; Opus 4.7 is $15/$75. Input prices are identical, but Opus's output is 25% more expensive. In benchmarks, Opus often leads on long-context reasoning and complex analysis; o1 leads on math and code where its reasoning tokens earn their keep. Your choice depends on workload — run evals on your specific prompts.
Can I migrate from OpenAI to Claude without rewriting my code?
Mostly yes. Anthropic's SDK has a similar shape to OpenAI's — messages, system prompt, tools, streaming. Key differences: Anthropic does not use the 'completions' endpoint (messages-only), tool-use schemas are slightly different, and system prompts are passed as a separate field rather than a message. Budget 4–8 hours per production service for a clean migration. Both providers support vision, tool calling, and structured output — capability parity is high.
Does Claude have a Batch API like OpenAI?
Yes. Anthropic's Batch API offers 50% off list pricing for asynchronous workloads with 24-hour turnaround, matching OpenAI's. For bulk embeddings, offline evaluation, and nightly enrichment, both providers offer the same discount structure.
Can one tool track both OpenAI and Claude costs?
Yes. Capped is a Chrome extension that tracks both providers from the same interface. It uses OpenAI's /v1/organization/costs endpoint and Anthropic's /v1/organizations/cost_report endpoint — both require read-only organization admin keys. Monthly cap is set in dollars; desktop notifications fire at 80%, 100%, and 150% of the cap regardless of which provider contributes what.
How much more expensive is Claude Opus output vs GPT-4o output?
Claude Opus 4.7 output costs $75 per million tokens. GPT-4o output costs $10 per million tokens. That is a 7.5x difference at the output layer. For any workload that generates long responses (summarization, long-form writing, reasoning), Opus will cost 7.5x more per response than GPT-4o.
Prices reflect publicly listed per-million-token rates as of April 2026. This article is updated quarterly. Worked examples assume 30-day months with flat daily request patterns; real production workloads spike. Cost-equivalence comparisons pair models at the comparable tier from each provider, not always at identical capability — for capability-matched comparisons, rely on the decision matrix and capability table rather than raw monthly cost.