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Model comparison

GPT-5.6 Luna vs Kimi K2.5

Updated August 10, 2026. Public scores include evidence status and uncertainty. They are not guarantees for a specific workload.

GPT-5.6 Luna

OpenAI

66.9/100

Estimated · Public rank #23

90% interval 56.4–77.3

Kimi K2.5

Moonshot AI

58.8/100

Supported · Public rank #64

90% interval 51.4–66.2

GPT-5.6 Luna has the higher public score estimate, 66.87 versus 58.81, but the 90% score intervals overlap. Treat that as a lead, not a settled winner.

9 results are shared. Category rows based on different benchmark sets are marked directional and do not name a winner.

Which one for your work

Recommendations appear only when a shared evidence basis or an explicit operating constraint supports the call. Secondary and unsupported use cases stay disclosed below the initial list.

  • Agentic work

    Tool use, computer use, and multi-step task completion

    GPT-5.6 Luna

    GPT-5.6 Luna leads on the same 2 weighted benchmark rows.

    Confidence: limited

  • Long documents

    Prompts that approach the documented context limit

    GPT-5.6 Luna

    GPT-5.6 Luna has the larger documented context window.

    Confidence: documented

  • Chat turn cost

    1K fresh input + 500 output tokens

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

Show secondary and unsupported calls
  • Cache-heavy agent loop cost

    200K cached + 20K fresh input + 10K output tokens

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Kimi K2.5 has no published cached-input rate, so cached tokens use its listed input rate.

    Confidence: rate-fallback

  • Repository review cost

    50K fresh input + 3K output tokens

    GPT-5.6 Luna

    GPT-5.6 Luna has the lower estimated token cost for this stated workload. Costs use the listed standard API rates.

    Confidence: listed-rates

  • Coding work

    Code generation, repair, and software-engineering tasks

    Not enough matched evidence

    The category averages use different weighted benchmark sets, so they are directional rather than like-for-like.

    Confidence: limited

What is actually comparable

Shared results can support a head-to-head reading. Results present for only one model describe coverage, not superiority.

Shared results
9
GPT-5.6 Luna only
13
Kimi K2.5 only
36
Like-for-like categories
2 / 8

3 categories use different evidence sets. Those rows remain visible for coverage context but do not name a winner.

Category results, on a stated basis

Each row states whether both averages use the same weighted benchmark set. Directional and not-comparable rows remain visible, but they never receive a winner in this template.

Agentic

Like-for-like
GPT-5.6 Luna
84.1
Kimi K2.5
55.0
Weighted basis
2 vs 2 rows
Reading
GPT-5.6 Luna leads

Multimodal

Like-for-like
GPT-5.6 Luna
78.4
Kimi K2.5
78.5
Weighted basis
1 vs 1 rows
Reading
Kimi K2.5 leads

Coding

Directional only
GPT-5.6 Luna
62.7
Kimi K2.5
59.4
Weighted basis
1 vs 4 rows
Reading
Directional only

Knowledge

Directional only
GPT-5.6 Luna
92.3
Kimi K2.5
56.9
Weighted basis
1 vs 4 rows
Reading
Directional only

Math

Directional only
GPT-5.6 Luna
73.6
Kimi K2.5
60.6
Weighted basis
2 vs 4 rows
Reading
Directional only

Reasoning

Not comparable
GPT-5.6 Luna
59.5
Kimi K2.5
61.0
Weighted basis
1 vs 1 rows
Reading
Not comparable

Multilingual

Not comparable
GPT-5.6 Luna
Not measured
Kimi K2.5
82.3
Weighted basis
0 vs 1 rows
Reading
Not comparable

Instruction following

Not comparable
GPT-5.6 Luna
Not measured
Kimi K2.5
93.9
Weighted basis
0 vs 1 rows
Reading
Not comparable

Shape of the matched evidence

Only shared public evidence is shown. Sparse evidence stays a ruled list rather than being closed into a radar shape.

Too few matched category axes support a radar. The ruled list below shows only shared benchmark results; positions use each benchmark’s normalized display scale when available.

What each workload costs

Three fixed token mixes turn per-token rates into comparable decisions. Each scenario states context fit and whether cached input had to fall back to the published list-input rate.

Chat turn

1K fresh input + 500 output tokens

GPT-5.6 Luna
$0.0008
Fits in one request
Kimi K2.5
$0.0021
Fits in one request

GPT-5.6 Luna has the lower modeled cost

Costs use the listed standard API rates.

Repository review

50K fresh input + 3K output tokens

GPT-5.6 Luna
$0.0136
Fits in one request
Kimi K2.5
$0.039
Fits in one request

GPT-5.6 Luna has the lower modeled cost

Costs use the listed standard API rates.

Cache-heavy agent loop

200K cached + 20K fresh input + 10K output tokens

GPT-5.6 Luna
$0.02
Fits in one request
Kimi K2.5
$0.162
Fits in one request
Cached input priced at the published list-input rate

GPT-5.6 Luna has the lower modeled cost

Kimi K2.5 has no published cached-input rate, so cached tokens use its listed input rate.

Specification differences

Sourced differences are shown directly. Missing facts stay explicit instead of being inferred from a model name or family.

Context window

Maximum documented context; output-token limits may be lower.

GPT-5.6 Luna

Kimi K2.5

256K

Cached-input rate

A missing cached-input rate falls back to the listed input rate only in the stated workload estimate.

GPT-5.6 Luna

$0.02 per 1M cached input tokens

OpenAI pricing

Kimi K2.5

Not published

Provider availability

GPT-5.6 Luna

Generally Available · OpenAI Responses API

OpenAI model catalog

Kimi K2.5

Not sourced

Reasoning profile

GPT-5.6 Luna

Reasoning

Kimi K2.5

Non-Reasoning

Weight access

GPT-5.6 Luna

Proprietary

Kimi K2.5

Open Weight

License

GPT-5.6 Luna

Proprietary

Kimi K2.5

Open Weight

Release date

GPT-5.6 Luna

2026-07-09

Kimi K2.5

2026-02-01

If you already use one of these models
Deployment change
The models list different providers, so authentication, endpoint behavior, limits, and feature support may change.
Quality signal
GPT-5.6 Luna has the higher public score estimate, 66.87 versus 58.81, but the 90% score intervals overlap.
Workload cost
Repository review: $0.0136 vs $0.039. Cache-heavy agent loop: $0.02 vs $0.162.
Context tradeoff
GPT-5.6 Luna has the larger documented window (1.05M).

Run the same representative tasks against both endpoints before changing production traffic.

Self-host vs API cost

Estimates at 50,000 req/day · 1000 tokens/req average.

GPT-5.6 Luna
API / mo$1,050
Self-host / moNot listed
Break-even
Proprietary model — self-hosting not applicable.
Kimi K2.5
API / mo$2,700
Self-host / mo$5,221
Break-even132M/day
Model the full break-even

Benchmark evidence

The full public result ledger is available for audit without forcing a wide desktop table onto a phone.

Browse raw public benchmark evidence58 rows

Agentic

  • Terminal-Bench 2.0

    GPT-5.6 Luna84.7%
    Source
    Kimi K2.550.8%
    Source

    GPT-5.6 Luna leads this result

  • BrowseComp

    GPT-5.6 Luna83.3%
    Source
    Kimi K2.560.6%
    Source

    GPT-5.6 Luna leads this result

  • OSWorld 2.0

    GPT-5.6 Luna45.6%
    Source
    Kimi K2.5

    Not directly comparable

  • CyberGym

    GPT-5.6 Luna77.9%
    Source
    Kimi K2.5

    Not directly comparable

  • ExploitGym

    GPT-5.6 Luna12.4%
    Source
    Kimi K2.5

    Not directly comparable

  • Toolathlon

    GPT-5.6 Luna53.4%
    Source
    Kimi K2.527.8%
    Source

    GPT-5.6 Luna leads this result

  • Claw-Eval

    GPT-5.6 Luna
    Kimi K2.552.3%
    Source

    Not directly comparable

  • QwenClawBench

    GPT-5.6 Luna
    Kimi K2.554.3%
    Source

    Not directly comparable

  • τ³-bench results

    GPT-5.6 Luna
    Kimi K2.565.7%
    Source

    Not directly comparable

  • DeepSearchQA

    GPT-5.6 Luna
    Kimi K2.577.1%
    Source

    Not directly comparable

  • DeepPlanning

    GPT-5.6 Luna
    Kimi K2.514.4%
    Source

    Not directly comparable

  • MCP Atlas

    GPT-5.6 Luna
    Kimi K2.529.5%
    Source

    Not directly comparable

  • MCP-Tasks

    GPT-5.6 Luna
    Kimi K2.559.1%
    Source

    Not directly comparable

  • WideResearch

    GPT-5.6 Luna
    Kimi K2.572.7%
    Source

    Not directly comparable

  • Gert Labs

    GPT-5.6 Luna
    Kimi K2.545.88%
    Source

    Not directly comparable

  • ResearchClawBench

    GPT-5.6 Luna
    Kimi K2.514.0%
    Source

    Not directly comparable

  • JobBench

    GPT-5.6 Luna
    Kimi K2.58.7%
    Source

    Not directly comparable

Coding

  • SWE-bench Pro

    GPT-5.6 Luna62.7%
    Source
    Kimi K2.550.7%
    Source

    GPT-5.6 Luna leads this result

  • Terminal-Bench 2.0

    GPT-5.6 Luna84.7%
    Source
    Kimi K2.5

    Not directly comparable

  • deepSwe

    GPT-5.6 Luna67.2%
    Source
    Kimi K2.5

    Not directly comparable

  • FrontierCode 1.1 Extended

    GPT-5.6 Luna55.1%
    Source
    Kimi K2.5

    Not directly comparable

  • cursorBench32

    GPT-5.6 Luna61.1%
    Source
    Kimi K2.5

    Not directly comparable

  • SWE-bench Verified

    GPT-5.6 Luna
    Kimi K2.576.8%
    Source

    Not directly comparable

  • SWE-bench Verified*

    GPT-5.6 Luna
    Kimi K2.570.8%
    Source

    Not directly comparable

  • LiveCodeBench v6

    GPT-5.6 Luna
    Kimi K2.585.0%
    Source

    Not directly comparable

  • SWE Multilingual

    GPT-5.6 Luna
    Kimi K2.573%
    Source

    Not directly comparable

  • SWE-Rebench

    GPT-5.6 Luna
    Kimi K2.558.5%
    Source

    Not directly comparable

  • React Native Evals

    GPT-5.6 Luna
    Kimi K2.577.2%
    Source

    Not directly comparable

  • SciCode

    GPT-5.6 Luna
    Kimi K2.548.7%
    Source

    Not directly comparable

Reasoning

  • ARC-AGI-2

    GPT-5.6 Luna59.5%
    Source
    Kimi K2.5

    Not directly comparable

  • ARC-AGI-3

    GPT-5.6 Luna0.2%
    Source
    Kimi K2.5

    Not directly comparable

  • LongBench v2

    GPT-5.6 Luna
    Kimi K2.561%
    Source

    Not directly comparable

Knowledge

  • GPQA

    GPT-5.6 Luna92.3%
    Source
    Kimi K2.587.6%
    Source

    GPT-5.6 Luna leads this result

  • GPQA-D

    GPT-5.6 Luna92.3%
    Source
    Kimi K2.587.6%
    Source

    GPT-5.6 Luna leads this result

  • HealthBench Professional

    GPT-5.6 Luna55.7%
    Source
    Kimi K2.5

    Not directly comparable

  • HealthBench Hard

    GPT-5.6 Luna32.0%
    Source
    Kimi K2.5

    Not directly comparable

  • SuperGPQA

    GPT-5.6 Luna
    Kimi K2.569.2%
    Source

    Not directly comparable

  • MMLU-Pro

    GPT-5.6 Luna
    Kimi K2.587.1%
    Source

    Not directly comparable

  • MMLU-Pro (Arcee)

    GPT-5.6 Luna
    Kimi K2.587.1%
    Source

    Not directly comparable

  • HLE

    GPT-5.6 Luna
    Kimi K2.530.1%
    Source

    Not directly comparable

Math

  • FrontierMath (legacy)

    GPT-5.6 Luna78.6%
    Source
    Kimi K2.5

    Not directly comparable

  • FrontierMath v2 (Tiers 1-3)

    GPT-5.6 Luna78.600%
    Source
    Kimi K2.527.900%
    Source

    GPT-5.6 Luna leads this result

  • FrontierMath v2 (Tier 4)

    GPT-5.6 Luna58.500%
    Source
    Kimi K2.54.200%
    Source

    GPT-5.6 Luna leads this result

  • AIME 2025

    GPT-5.6 Luna
    Kimi K2.596.1%
    Source

    Not directly comparable

  • AIME26

    GPT-5.6 Luna
    Kimi K2.595.8%
    Source

    Not directly comparable

  • AIME25 (Arcee)

    GPT-5.6 Luna
    Kimi K2.596.3%
    Source

    Not directly comparable

  • HMMT Feb 2025

    GPT-5.6 Luna
    Kimi K2.595.4%
    Source

    Not directly comparable

  • HMMT Nov 2025

    GPT-5.6 Luna
    Kimi K2.591.1%
    Source

    Not directly comparable

  • HMMT Feb 2026

    GPT-5.6 Luna
    Kimi K2.587.1%
    Source

    Not directly comparable

  • MMAnswerBench

    GPT-5.6 Luna
    Kimi K2.581.8%
    Source

    Not directly comparable

Multilingual

  • MMLU-ProX

    GPT-5.6 Luna
    Kimi K2.582.3%
    Source

    Not directly comparable

  • NOVA-63

    GPT-5.6 Luna
    Kimi K2.556.0%
    Source

    Not directly comparable

Multimodal

  • MMMU-Pro

    GPT-5.6 Luna78.4%
    Source
    Kimi K2.578.5%
    Source

    Kimi K2.5 leads this result

  • MMMU-Pro w/ Python

    GPT-5.6 Luna79.5%
    Source
    Kimi K2.5

    Not directly comparable

  • Video-MME

    GPT-5.6 Luna
    Kimi K2.587.4%
    Source

    Not directly comparable

  • MMVU

    GPT-5.6 Luna
    Kimi K2.580.4%
    Source

    Not directly comparable

  • VideoMMMU

    GPT-5.6 Luna
    Kimi K2.586.6%
    Source

    Not directly comparable

Instruction following

  • IFEval

    GPT-5.6 Luna
    Kimi K2.593.9%
    Source

    Not directly comparable

Frequently asked questions

Which is better, GPT-5.6 Luna or Kimi K2.5?

GPT-5.6 Luna has the higher public score estimate, 66.87 versus 58.81, but the 90% score intervals overlap. The higher estimate is not a decisive winner because the uncertainty ranges overlap.

Which is better for coding, GPT-5.6 Luna or Kimi K2.5?

The current coding averages use different weighted benchmark sets, so BenchLM does not name a winner from them. Read the shared benchmark rows directly and test the models on the same task set.

Which is better for agentic tasks, GPT-5.6 Luna or Kimi K2.5?

GPT-5.6 Luna leads the like-for-like agentic tasks comparison across 2 shared weighted benchmark rows.

Which costs less, GPT-5.6 Luna or Kimi K2.5?

For the stated presets, chat costs $0.0008 on GPT-5.6 Luna and $0.0021 on Kimi K2.5; repository review costs $0.0136 and $0.039; the cache-heavy agent loop costs $0.02 and $0.162. Kimi K2.5 has no published cached-input rate, so cached tokens use its listed input rate.

Which has the larger context window, GPT-5.6 Luna or Kimi K2.5?

GPT-5.6 Luna has the larger documented context window: 1.05M, compared with 256K.

Related comparisons

Last updated August 10, 2026

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