GPT-5 Mini vs Kimi K2 Thinking vs Mistral Medium 3

GPT-5 Mini is the better all-round choice, scoring 65/100 against Kimi K2 Thinking (58) and Mistral Medium 3 (53). It leads on price, inputs & features and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

GPT-5 Mini is cheaper at $0.25 input / $2.00 output per million tokens (official OpenAI API price). Mistral Medium 3 costs $0.40 input / $2.00 output per million tokens (official Mistral API price); Kimi K2 Thinking costs $0.60 input / $2.50 output per million tokens (median across 10 API providers). At a typical mix of three input tokens to one output token, that is $0.688 per million tokens for GPT-5 Mini versus $0.80 for Mistral Medium 3 (1.2× as much) and $1.07 for Kimi K2 Thinking (1.6× as much).

Kimi K2 Thinking scores higher on the Capabilities Index (ECI): Kimi K2 Thinking 146.0 (#72 of 148), GPT-5 Mini 145.5 (#77 of 148) and Mistral Medium 3 134.1 (#117 of 148). The confidence ranges of the top two overlap (143.4–147.6 vs 143.6–147.0), so treat the gap as small. On individual benchmarks: GPQA Diamond — Kimi K2 Thinking 84.2%, GPT-5 Mini 75.0%, Mistral Medium 3 59.5%; OTIS Mock AIME 2024–2025 — GPT-5 Mini 86.7%, Kimi K2 Thinking 83.1%, Mistral Medium 3 32.2%.

There are no published SWE-bench Verified results for Kimi K2 Thinking and Mistral Medium 3 yet, so there is no like-for-like coding score. On overall capability, Kimi K2 Thinking leads, which tends to carry over to coding, but test on your own codebase. All three support tool calling for agent workflows.

GPT-5 Mini has the largest context window at 400,000 tokens, against 262,144 for Kimi K2 Thinking and 131,072 for Mistral Medium 3. Maximum output per response: GPT-5 Mini up to 128,000, Kimi K2 Thinking up to 262,144, Mistral Medium 3 up to 131,072 tokens.

GPT-5 Mini accepts text and images; Kimi K2 Thinking accepts text; Mistral Medium 3 accepts text and images. GPT-5 Mini handles the widest range of inputs.

Kimi K2 Thinking publishes its weights and can be self-hosted; GPT-5 Mini and Mistral Medium 3 is proprietary.

Kimi K2 Thinking is the newest, released Nov 6, 2025. GPT-5 Mini came out Aug 7, 2025; Mistral Medium 3 came out May 7, 2025. Knowledge cutoff: GPT-5 Mini May 30, 2024, Kimi K2 Thinking Aug 2024, Mistral Medium 3 May 2025.

Each model gets a 0–100 score on capability (50%, independent benchmark results); price (25%, blended price per million tokens (3 input : 1 output), log scale); inputs & features (15%, image, PDF, audio and video input, tool calling, structured output and reasoning); context window (10%, maximum tokens per request, log scale). Dimensions missing for any model are dropped and the remaining weights rescaled, so every model is judged on the same evidence. Specs and prices come from public model listings and the labs’ own API pages; capability scores come from independent benchmark runs. Data updated Oct 4, 2026.