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OpenAI: GPT-5 Chat vs OpenAI: GPT-5.1 Chat

Head-to-head API cost, context, and performance comparison. Synced at 2:29:34 PM.

Executive Summary

When evaluating OpenAI: GPT-5 Chat against OpenAI: GPT-5.1 Chat, the pricing structure is a key differentiator. Both models are remarkably similar in API costs.

However, when looking at raw reasoning capabilities, OpenAI: GPT-5.1 Chat leads with a statistical ELO score of 1480. For tasks involving complex logic, coding, or instruction-following, developers might prefer OpenAI: GPT-5.1 Chat, provided their budget allows for the API burn rate.

Raw Technical comparison

Metric
OpenAI: GPT-5 Chat
OpenAI: GPT-5.1 Chat
Performance (ELO)
1478
1480
Input Cost / 1M
$1.25
$1.25
Output Cost / 1M
$10.00
$10.00
Context Window
128,000 tokens
128,000 tokens

Verdict

If you are looking for pure performance and capability, OpenAI: GPT-5.1 Chat is statistically superior. However, if API burn rate is the primary concern, Tie wins out aggressively in pricing.

People Also Ask

Is OpenAI: GPT-5 Chat cheaper than OpenAI: GPT-5.1 Chat?

No. OpenAI: GPT-5.1 Chat is the more cost-effective model, operating at a lower price point per 1 million tokens.

Which model has the larger context window?

Both models offer an identical context window of 128,000 tokens.

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