OpenAI o4-mini API Pricing 2026

o4-mini at $1.10/MTok input — the affordable reasoning model. Compare vs Claude Haiku, Gemini Flash Thinking, and o3. When reasoning pays and when it's overkill.

OpenAI o4-mini Pricing

Model Input (per 1M tokens) Output (per 1M tokens) Cache Read Notes
o4-mini Best value reasoning $1.10 $4.40 $0.275 (75% off) Extended chain-of-thought reasoning
o3 $10.00 $40.00 $2.50 (75% off) ~9× more expensive; use for frontier math/coding

o4-mini vs Claude Haiku vs Gemini Flash — Full Comparison

Model Input Output Cache Read Context Reasoning
Gemini 2.0 Flash Cheapest $0.10 $0.40 $0.025 1M tokens No (fast mode)
Gemini 2.0 Flash Thinking $0.10 $3.50 $0.025 1M tokens Yes (built-in)
GPT-4o-mini $0.15 $0.60 $0.075 128k tokens No
Claude Haiku 4.5 Best cache $0.80 $4.00 $0.08 (90% off) 200k tokens No (fast mode)
o4-mini This page $1.10 $4.40 $0.275 (75% off) 128k tokens Yes (extended thinking)
Claude Sonnet 4.6 $3.00 $15.00 $0.30 (90% off) 200k tokens Yes (extended thinking)

Haiku vs o4-mini rule of thumb: If your task doesn't require step-by-step reasoning (classification, extraction, summarization, simple Q&A), Claude Haiku at $0.80/MTok is cheaper and faster. If your task benefits from working through a problem (multi-step math, logic puzzles, code debugging with multiple hypotheses), o4-mini's reasoning mode justifies the $0.30/MTok premium. Test both before committing to either.

o4-mini Strengths and Tradeoffs

Hard reasoning: o4-mini wins over Haiku

For multi-step math, complex code debugging, and formal logic, o4-mini's chain-of-thought reasoning outperforms Claude Haiku significantly. Haiku is fast and cheap but is not a reasoning model — it doesn't do step-by-step thinking before answering.

Cost at scale: Haiku/Gemini Flash win

For high-volume workloads where tasks are simple (classification, extraction, routing), Haiku ($0.80) or Gemini Flash ($0.10) are cheaper. o4-mini also produces longer outputs due to thinking tokens, increasing per-call cost beyond sticker input price.

Context window: Claude Haiku wins

Claude Haiku has a 200k token context window vs o4-mini's 128k. For long-document analysis or RAG with large retrieved contexts, Haiku handles more text per call. Gemini Flash Thinking has a 1M token context — unmatched for very long contexts.

Caching: Claude Haiku wins

Claude Haiku's 90% caching discount ($0.08/MTok cache reads) beats o4-mini's 75% off ($0.275/MTok). For apps with large repeated system prompts, Haiku's effective cost with caching can be 3× lower than o4-mini's cached price.

When to Choose o4-mini vs Alternatives

Scenario Best Model Reason
Multi-step math or science problems o4-mini Reasoning mode outperforms non-reasoning models on formal step-by-step problems
Code debugging (complex) o4-mini Extended thinking helps with hypothesis testing across multiple code paths
Text classification / extraction Claude Haiku / Gemini Flash No reasoning needed; Haiku/Flash are 8× cheaper and faster
Summarization of long documents Claude Haiku (200k) or Gemini Flash (1M) Larger context windows handle more text; reasoning not needed for summarization
Agentic workflows with tool use Claude Sonnet 4.6 200k context, 90% caching, stronger instruction following for multi-step agents
Frontier math (AIME-level) o3 o4-mini may hit quality ceiling on hardest formal reasoning — try o4-mini first

Monthly Cost Comparison at Scale

For a reasoning-enabled coding assistant processing 50M input tokens/month with 15M output tokens:

Model Input Cost Output Cost Monthly Total Reasoning?
Gemini Flash Thinking $5 $52.50 $57.50 Yes
Claude Haiku 4.5 $40 $60 $100 No
o4-mini $55 $66 $121 Yes
Claude Sonnet 4.6 (no cache) $150 $225 $375 Yes
o3 $500 $600 $1,100 Yes

Calculate Your o4-mini vs Claude Cost

Paste your actual prompt to see exact token counts and compare o4-mini, Claude Haiku, Sonnet, and Gemini Flash — with reasoning overhead and cache scenarios.

Open the LLM Pricing Calculator →

Frequently Asked Questions

How much does an o4-mini API call cost?

At $1.10/MTok input and $4.40/MTok output: a typical reasoning call with 1,500 tokens input and 2,000 tokens output (including thinking) costs approximately $0.0017 input + $0.0088 output = ~$0.01 per call. Reasoning models produce more output tokens than non-reasoning models because thinking is included in the output count. For very complex problems with long thinking chains (5,000–10,000 thinking tokens), costs can reach $0.02–$0.04 per call. Measure your actual usage before scaling.

Is o4-mini available on Azure?

Yes. o4-mini is available through Azure OpenAI Service with enterprise SLAs, data residency, and compliance certifications (SOC 2, HIPAA BAA). Azure pricing mirrors OpenAI direct pricing. For enterprise teams already using Azure infrastructure, deploying o4-mini via Azure OpenAI provides VNet integration, private endpoints, and Azure Active Directory integration that aren't available on the direct OpenAI API.

Does o4-mini have a free tier?

OpenAI provides trial credits for new accounts, which can be used on o4-mini. Beyond trial credits, o4-mini is pay-per-token at $1.10/MTok input. There is no sustained free tier for o4-mini on the production API. For free experimentation, ChatGPT's web interface uses o4-mini in its reasoning mode (with usage caps on free accounts). For production API access, you'll need a paid OpenAI account with billing enabled.

Can o4-mini replace Claude Haiku for my chatbot?

It depends on your bot's tasks. For a customer support chatbot handling FAQs, order lookups, and simple conversations, Claude Haiku is cheaper and fast enough — reasoning doesn't help here. For a technical support bot that needs to diagnose complex multi-step issues, debug code snippets, or reason about system configurations, o4-mini's thinking mode can meaningfully improve answer quality. Estimate your monthly volume first: at 10M tokens/month, the difference is ~$30 (Haiku) vs ~$55 (o4-mini) — worth testing quality before optimizing cost.

What's the relationship between o4-mini and o3-mini?

o4-mini is OpenAI's current recommended budget reasoning model, succeeding the earlier o3-mini. They share similar pricing ($1.10/$4.40 MTok) but o4-mini has improved capabilities, especially for code and multimodal tasks. If you see documentation referencing o3-mini, the equivalent current model is o4-mini. OpenAI has been phasing out the -mini naming convention to align with their main model version numbers (o3, o4-mini, etc.).

Also see: OpenAI o3 Pricing · Claude Haiku Pricing · Claude Sonnet Pricing · Gemini API Pricing · LLM Cost Comparison 2026