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Grok vs o3

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Compare Grok vs o3 — features, pricing, performance, and which is better for your use case.

Try Both Side by Side Start Chatting AI Arena

Head-to-Head

Grok o3
Provider xAI OpenAI
Category Chat Chat
Context window 256000 tokens 200000 tokens
Cost per message Free.ai tokens (estimate) ~6750 tokens ~3825 tokens
Free to use without purchase? No — premium external model
Needs purchased tokens — $5 buys 200K		 No — premium external model
Needs purchased tokens — $5 buys 200K
Model page on Free.ai View Grok → View o3 →
Grok

xAI: Grok 4 is an AI model by xAI on Free.ai. It supports up to 256,000 tokens of context. Costs approximately 6,750 tokens per message. Try xAI: Grok 4 instantly — no sign up needed. Compare it side-by-side with other models.

o3

OpenAI: o3 is an AI model by OpenAI on Free.ai. It supports up to 200,000 tokens of context. Costs approximately 3,825 tokens per message. Try OpenAI: o3 instantly — no sign up needed. Compare it side-by-side with other models.

Which should you use?

Benchmarks can only tell you so much. The honest answer for any real workload is: send the same prompt to both and read the two answers yourself.

Free.ai's compare tool lets you do that in a single view, and the AI Arena collects community votes on blind responses if you want a broader signal.

Try Grok and o3 side by side

Same prompt, two answers. Both are premium external models — use requires purchased tokens ($5 = 200K).

Open Compare Tool
Or try a free self-hosted model instead (Qwen, Mistral, DeepSeek, etc.) — no purchase needed.

FAQ

Grok vs o3 is a side-by-side comparison of two AI models. Grok is built by xAI, and o3 by OpenAI. Send them the same prompt at /chat/compare/ and read both answers side by side.

Not free — Grok and o3 are premium external models routed through third-party providers, so they require purchased tokens (starting at $5 for 200,000 tokens). Only Free.ai's self-hosted open-source models like Qwen, Mistral, DeepSeek, FLUX, Kokoro, and Whisper are free to use without purchase.

Depends on your workload. Send the same prompt to both at /chat/compare/ and judge the two answers directly — benchmarks can only tell you so much. The AI Arena also collects community votes on blind responses if you want a broader signal.

Yes — Grok and o3 are premium external models that need purchased tokens. You can create a free Free.ai account and buy tokens starting at $5 for 200K. Our self-hosted open-source models (Qwen, Mistral, DeepSeek, FLUX, Kokoro, Whisper, etc.) are free with an account and work without any purchase.

The compare tool sends the same prompt to Grok and o3 in parallel and streams both responses side by side. Each panel has its own conversation history, so you can follow up differently on each side.

Yes. Each panel has its own model picker — change Grok or o3 to any of 370+ models at any time. The conversation history on each side is preserved.

Free.ai bills in tokens, not per-message. A typical chat turn on Grok uses about 6,750 Free.ai tokens per message; on o3, about 3,825 Free.ai tokens per message. $5 buys 200,000 tokens and they never expire. Self-hosted open-source models are free up to your daily allowance.

Grok supports 256,000 tokens of context; o3 supports 200,000 tokens. Context window is how much text the model can read in a single conversation before older messages start being trimmed.

Yes. Signed-in users have their compare sessions saved automatically — see the sidebar on /chat/compare/ for past comparisons. Each comparison stores both sides (Model A and Model B) independently so you can revisit exact responses.

Only for external models. Grok runs on xAI's servers (premium); your prompt is routed there through our external-model gateway when you use this pair. Self-hosted open-source models like Qwen, Mistral, DeepSeek, FLUX, Kokoro, and Whisper run on Free.ai's own GPUs — nothing leaves our infrastructure.

Yes. Both Grok and o3 are accessible through the Free.ai API — one Bearer token, OpenAI-compatible chat/completions. Paid models require purchased tokens (no API access from the daily free pool).

Check the individual model pages — /apps/x-ai-grok-4/ and /apps/openai-o3/ — for each model's specs. For head-to-head quality signal, look at the /arena/ leaderboard which ranks models by blind community votes. For your own workload, nothing beats sending the same prompts through the compare tool.

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