xAI Grok vs OpenAI GPT — API Pricing Comparison
Compare all xAI Grok and OpenAI GPT models side by side. Grok 3 matches GPT-5.5 pricing at $30/M but offers 8x less context. OpenAI dominates on value across every tier.
Pricing data verified: May 14, 2026
All Models Compared
Every xAI and OpenAI model, ranked by input price.
| Model | Provider | Tier | Input (per 1M) | Output (per 1M) | Context |
|---|---|---|---|---|---|
| GPT-oss 20B | OpenAI | Budget | $0.08 | $0.35 | 128K |
| GPT-oss 120B | OpenAI | Budget | $0.15 | $0.60 | 128K |
| GPT-4o mini | OpenAI | Budget | $0.15 | $0.60 | 128K |
| GPT-5 mini | OpenAI | Budget | $0.25 | $2.00 | 272K |
| GPT-5 | OpenAI | Premium | $1.25 | $10.00 | 272K |
| GPT-5.3 Codex | OpenAI | Mid | $1.75 | $14.00 | 400K |
| GPT-4o | OpenAI | Mid | $2.50 | $10.00 | 128K |
| Grok 3 Mini | xAI | Mid | $3.00 | $5.00 | 128K |
| GPT-5.5 | OpenAI | Premium | $5.00 | $30.00 | 1M |
| Grok 3 | xAI | Premium | $30.00 | $150.00 | 128K |
| GPT-5.5 Pro | OpenAI | Premium | $30.00 | $180.00 | 1M |
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Which Should You Choose?
Chatbot / Customer Support
High volume, short responses. Cost per message matters most. xAI has no budget models — every request costs significantly more.
Code Generation
Complex reasoning, longer outputs. Quality and accuracy matter. Both have capable models but OpenAI has far more options.
Long Document Analysis
Processing large documents, legal contracts, or codebases. Context window is critical. xAI models max out at 128K.
Startup MVP / Side Project
Minimize costs while building. Need reliable API at the lowest price point. xAI has no free tier or budget models.
Enterprise / Premium
Highest quality for complex reasoning. Budget less critical than accuracy and ecosystem fit.
X/Twitter Integration
Need real-time X data, social media analysis, or Elon's ecosystem. This is xAI's unique advantage.
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Frequently Asked Questions
Is xAI Grok or OpenAI cheaper for API usage?
OpenAI offers significantly more budget-friendly options. GPT-5 ($1.25/$10.00) is far cheaper than Grok 3 ($30/$150) and delivers more value with 272K context versus Grok 3's 128K. For budget use cases, GPT-oss 20B ($0.08/$0.35) and GPT-4o mini ($0.15/$0.60) have no xAI equivalents. Grok 3 Mini ($3/$5) competes with GPT-5 on input but costs 50% less on output, though with half the context window.
What is the cheapest xAI Grok model?
Grok 3 Mini at $3.00 input / $5.00 output per 1M tokens is xAI's cheapest model. It's positioned as a mid-tier model — more expensive than OpenAI's budget options (GPT-5 mini at $0.25/$2.00, GPT-oss 20B at $0.08/$0.35) but competitive with GPT-5 ($1.25/$10.00) on output costs.
Does Grok 3 have a larger context window than GPT-5.5?
No, Grok 3 has a smaller context window. Grok 3 supports 128K tokens while GPT-5.5 supports 1M tokens — nearly 8x more. Even GPT-5 at $1.25/$10.00 offers 272K context, more than double Grok 3's capacity. For tasks requiring large context (document analysis, codebase review), OpenAI models provide substantially more headroom.
Grok 3 vs GPT-5.5: which should I choose?
GPT-5.5 is the better value. At $5/$30 per 1M tokens, it costs 83% less on input and 80% less on output than Grok 3 ($30/$150), while offering 8x more context (1M vs 128K). Choose Grok 3 only if you specifically need xAI's training data (X/Twitter integration) or prefer the Grok ecosystem. For most production use cases, GPT-5 or GPT-5.5 provide better cost-efficiency.
Does xAI offer a free API tier?
xAI does not currently offer a free API tier for Grok models. All usage is billed. By contrast, Google offers a generous free tier (1M tokens/day for Gemini Flash models) and OpenAI provides a one-time $5 credit for new accounts. If budget is a concern, consider starting with Google's free tier or OpenAI's GPT-oss models ($0.08/$0.35).