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Comparison · 2 models · Updated Oct 4, 2026

GPT-5.4 mini vs Kimi K2 Thinking

GPT-5.4 mini comes out ahead, 63 to 58 on our weighted score, though Kimi K2 Thinking is 36% cheaper per token.

  1. Our pick

    OpenAI

    GPT-5.4 mini

    Released Mar 17, 2026

    63/100
    • ECI148.8
    • Price$0.75 / $4.50
    • Context400K
    Full specs Remove GPT-5.4 mini

  2. Moonshot AI

    Kimi K2 Thinking

    Released Nov 6, 2025

    58/100
    • ECI146.0
    • Price$0.60 / $2.50
    • Context262K
    Full specs Remove Kimi K2 Thinking

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

GPT-5.4 mini is our pick

GPT-5.4 mini is the better all-round choice, scoring 63/100 against Kimi K2 Thinking (58). It leads on capability, inputs & features and context window. Kimi K2 Thinking wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityGPT-5.4 miniCapabilities Index (ECI): GPT-5.4 mini 148.8 · Kimi K2 Thinking 146.0
  • Lowest priceKimi K2 ThinkingKimi K2 Thinking $1.07 · GPT-5.4 mini $1.69 per 1M tokens (3:1 blend)
  • Longest contextGPT-5.4 miniGPT-5.4 mini 400,000 · Kimi K2 Thinking 262,144 tokens
  • Widest inputsGPT-5.4 miniGPT-5.4 mini: Text, Images · Kimi K2 Thinking: Text
  • Self-hostingKimi K2 ThinkingPublishes downloadable weights
How the score is built
MeasureWeightGPT-5.4 miniKimi K2 Thinking
CapabilityCapabilities Index (ECI)50%7773
Price25%3948
Inputs & features15%7035
Context window10%4437
Overall100%63/10058/100
02 — Side by side

Every spec in one table

Highlighted cells lead their row. Dashes mean the data is not published.

GPT-5.4 mini vs Kimi K2 Thinking specifications side by side
SpecificationGPT-5.4 miniOpenAIKimi K2 ThinkingMoonshot AI
Capability
Capabilities Index (ECI)148.8 (best)146.0
ECI rank#56 of 148 (best)#72 of 148
GPQA DiamondGraduate-level science questions86.9% (best)84.2%
FrontierMath Tiers 1–3Research-level mathematics51.2%—
OTIS Mock AIME 2024–2025Competition mathematics88.9% (best)83.1%
SimpleQA VerifiedShort factual questions29.4%—
Price per million tokens
Input$0.75$0.60 (best)
Output$4.50$2.50 (best)
Cached input$0.075—
Blended (3:1)$1.69$1.07 (best)
Long-context rateSame rateSame rate
Price sourceOfficial OpenAI APIMedian of 10 providers
Limits
Context window400,000 tokens (best)262,144 tokens
Max output128,000 tokens262,144 tokens (best)
Inputs and features
TextYesYes
ImagesYesNo
PDFsNoNo
AudioNoNo
VideoNoNo
ReasoningYeslow · medium · high · xhighYes
Tool callingYesYes
Structured outputYesNo
Availability
WeightsProprietaryOpen
API model IDgpt-5.4-mini—
API providers29 (best)10
ReleasedMar 17, 2026Nov 6, 2025
Knowledge cutoffAug 31, 2025Aug 2024
03 — Cost

What would a month cost?

Enter your expected volume in millions of tokens. List prices only; caching and batch discounts would lower these.

  • GPT-5.4 mini$16.50
  • Kimi K2 Thinking$11.00
04 — Questions

Which should you choose?

Which is better: GPT-5.4 mini or Kimi K2 Thinking?

GPT-5.4 mini is the better all-round choice, scoring 63/100 against Kimi K2 Thinking (58). It leads on capability, inputs & features and context window. Kimi K2 Thinking wins on price. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, GPT-5.4 mini or Kimi K2 Thinking?

Kimi K2 Thinking is cheaper at $0.60 input / $2.50 output per million tokens (median across 10 API providers). GPT-5.4 mini costs $0.75 input / $4.50 output per million tokens (official OpenAI API price). At a typical mix of three input tokens to one output token, that is $1.07 per million tokens for Kimi K2 Thinking versus $1.69 for GPT-5.4 mini (1.6× as much).

Which scores higher on benchmarks?

GPT-5.4 mini scores higher on the Capabilities Index (ECI): GPT-5.4 mini 148.8 (#56 of 148) and Kimi K2 Thinking 146.0 (#72 of 148). The confidence ranges of the top two overlap (147.1–150.5 vs 143.4–147.6), so treat the gap as small. On individual benchmarks: GPQA Diamond — GPT-5.4 mini 86.9%, Kimi K2 Thinking 84.2%; OTIS Mock AIME 2024–2025 — GPT-5.4 mini 88.9%, Kimi K2 Thinking 83.1%.

Which is better for coding?

There are no published SWE-bench Verified results for GPT-5.4 mini and Kimi K2 Thinking yet, so there is no like-for-like coding score. On overall capability, GPT-5.4 mini leads, which tends to carry over to coding, but test on your own codebase. Both support tool calling for agent workflows.

Which has the bigger context window?

GPT-5.4 mini has the largest context window at 400,000 tokens, against 262,144 for Kimi K2 Thinking. Maximum output per response: GPT-5.4 mini up to 128,000, Kimi K2 Thinking up to 262,144 tokens.

Which can read images, PDFs, audio or video?

GPT-5.4 mini accepts text and images; Kimi K2 Thinking accepts text. GPT-5.4 mini handles the widest range of inputs.

Are any of these open source?

Kimi K2 Thinking publishes its weights and can be self-hosted; GPT-5.4 mini is proprietary.

Which is newer?

GPT-5.4 mini is the newest, released Mar 17, 2026. Kimi K2 Thinking came out Nov 6, 2025. Knowledge cutoff: GPT-5.4 mini Aug 31, 2025, Kimi K2 Thinking Aug 2024.

How do you decide the winner?

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.

05 — Keep comparing

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