o3 vs Mistral Small 3.1

Compare o3 and Mistral Small 3.1: pricing, performance, context window, latency, and best use cases. Side-by-side comparison on XALEN.

Updated 2026-05-21 · By Abhishek Raj · Our methodology

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Feature o3 Mistral Small 3.1
CategoryReasoningCompact
Parameters~1T24B
Context Window200K128K
Input Price$0.10/1M tokens$0.02/1M tokens
Output Price$0.40/1M tokens$0.04/1M tokens
Latency~2000ms~120ms

Choose o3 when:

  • ✓ Complex calculations
  • ✓ Multi-factor analysis
  • ✓ Research-grade work
Key Strengths:

Extended thinking, Complex logic, Mathematical reasoning

Choose Mistral Small 3.1 when:

  • ✓ Lightweight tasks
  • ✓ Classification
  • ✓ Simple generation
Key Strengths:

128K context, Low cost, Fast

Verdict: o3 vs Mistral Small 3.1

For cost efficiency, Mistral Small 3.1 wins at $0.02/1M input tokens. For speed, Mistral Small 3.1 is faster at ~120ms. o3 excels at Complex calculations while Mistral Small 3.1 is better for Lightweight tasks. Both are available on XALEN through a single API — try them in the Playground to see which fits your workload.

Detailed Analysis

Pricing Comparison

o3 costs $0.10/1M input tokens and $0.40/1M output tokens. Mistral Small 3.1 costs $0.02 input and $0.04 output. Mistral Small 3.1 is 5.0x cheaper on input tokens. XALEN offers batch processing at 50% discount on both models.

Performance & Context

o3 has a 200K context window with ~2000ms latency. Mistral Small 3.1 offers 128K context at ~120ms. o3 has the larger context window.

Best For

o3 (Reasoning) is optimized for: Complex calculations, Multi-factor analysis, Research-grade work. Mistral Small 3.1 (Compact) works best for: Lightweight tasks, Classification, Simple generation.

Try Both on XALEN

Both models are available through XALEN's OpenAI-compatible API. Switch between them by changing the model parameter:

from xalen import XALEN

client = XALEN(api_key="xln_test_YOUR_KEY")

# Use o3
response_a = client.chat.completions.create(
    model="o3",
    messages=[{"role": "user", "content": "Your question here"}]
)

# Use Mistral Small 3.1
response_b = client.chat.completions.create(
    model="mistral-small-3-1",
    messages=[{"role": "user", "content": "Your question here"}]
)

Start Building with XALEN

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Get API Key Try in Playground

Frequently Asked Questions

Which is better, o3 or Mistral Small 3.1?

o3 (Reasoning, ~1T) offers Extended thinking. Mistral Small 3.1 (Compact, 24B) offers 128K context. Choose o3 for Complex calculations or Mistral Small 3.1 for Lightweight tasks.

How much does o3 cost vs Mistral Small 3.1?

o3: $0.10/1M input, $0.40/1M output. Mistral Small 3.1: $0.02/1M input, $0.04/1M output. Both available on XALEN with batch processing at 50% discount.

Can I use both models on XALEN?

Yes. XALEN provides 200+ models through a single OpenAI-compatible API. Switch between o3 and Mistral Small 3.1 by changing the model parameter. No code changes needed.

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Last updated: 2026-05-21. Pricing and specifications may change. Check pricing page for latest rates.