ZMIME
Comparison · 2 models · Updated Oct 4, 2026

Kimi K2.5 vs Nemotron 3 Ultra 550B A55B

Kimi K2.5 comes out ahead, 65 to 62 on our weighted score, though Nemotron 3 Ultra 550B A55B is 17% cheaper per token.

  1. Our pick

    Moonshot AI

    Kimi K2.5

    Released Jan 27, 2026

    65/100
    • ECI148.0
    • Price$0.60 / $3.00
    • Context262K
    Full specs Remove Kimi K2.5

  2. NVIDIA

    Nemotron 3 Ultra 550B A55B

    Released Jun 4, 2026

    62/100
    • ECI146.2
    • Price$0.50 / $2.50
    • Context1M
    Full specs Remove Nemotron 3 Ultra 550B A55B

  3. Add a model

    Make it a three-way comparison.

01 — Verdict

Kimi K2.5 is our pick

Kimi K2.5 is the better all-round choice, scoring 65/100 against Nemotron 3 Ultra 550B A55B (62). It leads on capability and inputs & features. Nemotron 3 Ultra 550B A55B wins on price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

  • CapabilityKimi K2.5Capabilities Index (ECI): Kimi K2.5 148.0 · Nemotron 3 Ultra 550B A55B 146.2
  • Lowest priceNemotron 3 Ultra 550B A55BNemotron 3 Ultra 550B A55B $1.00 · Kimi K2.5 $1.20 per 1M tokens (3:1 blend)
  • Longest contextNemotron 3 Ultra 550B A55BNemotron 3 Ultra 550B A55B 1,000,000 · Kimi K2.5 262,144 tokens
  • Widest inputsKimi K2.5Kimi K2.5: Text, Images, Video · Nemotron 3 Ultra 550B A55B: Text
  • Self-hostingAll open weightsEvery model here can be downloaded and run on your own hardware
How the score is built
MeasureWeightKimi K2.5Nemotron 3 Ultra 550B A55B
CapabilityCapabilities Index (ECI)50%7673
Price25%4650
Inputs & features15%8045
Context window10%3760
Overall100%65/10062/100
02 — Side by side

Every spec in one table

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

Kimi K2.5 vs Nemotron 3 Ultra 550B A55B specifications side by side
SpecificationKimi K2.5Moonshot AINemotron 3 Ultra 550B A55BNVIDIA
Capability
Capabilities Index (ECI)148.0 (best)146.2
ECI rank#58 of 148 (best)#70 of 148
GPQA DiamondGraduate-level science questions87.6% (best)85.4%
OTIS Mock AIME 2024–2025Competition mathematics92.2% (best)86.7%
SWE-bench VerifiedFixing real GitHub issues73.8%—
SimpleQA VerifiedShort factual questions34.3%—
Price per million tokens
Input$0.60$0.50 (best)
Output$3.00$2.50 (best)
Cached input—$0.15
Blended (3:1)$1.20$1.00 (best)
Long-context rateSame rateSame rate
Price sourceMedian of 21 providersOfficial Nvidia API
Limits
Context window262,144 tokens1,000,000 tokens (best)
Max output262,144 tokens (best)128,000 tokens
Inputs and features
TextYesYes
ImagesYesNo
PDFsNoNo
AudioNoNo
VideoYesNo
ReasoningYesYes
Tool callingYesYes
Structured outputYesYes
Availability
WeightsOpenOpen
API model ID—nvidia/nemotron-3-ultra-550b-a55b
API providers2121
ReleasedJan 27, 2026Jun 4, 2026
Knowledge cutoffJan 2025—
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.

  • Kimi K2.5$12.00
  • Nemotron 3 Ultra 550B A55B$10.00
04 — Questions

Which should you choose?

Which is better: Kimi K2.5 or Nemotron 3 Ultra 550B A55B?

Kimi K2.5 is the better all-round choice, scoring 65/100 against Nemotron 3 Ultra 550B A55B (62). It leads on capability and inputs & features. Nemotron 3 Ultra 550B A55B wins on price and context window. The score weighs capability 50%, price 25%, inputs & features 15%, context window 10%.

Which is cheaper, Kimi K2.5 or Nemotron 3 Ultra 550B A55B?

Nemotron 3 Ultra 550B A55B is cheaper at $0.50 input / $2.50 output per million tokens (official Nvidia API price). Kimi K2.5 costs $0.60 input / $3.00 output per million tokens (median across 21 API providers). At a typical mix of three input tokens to one output token, that is $1.00 per million tokens for Nemotron 3 Ultra 550B A55B versus $1.20 for Kimi K2.5 (1.2× as much).

Which scores higher on benchmarks?

Kimi K2.5 scores higher on the Capabilities Index (ECI): Kimi K2.5 148.0 (#58 of 148) and Nemotron 3 Ultra 550B A55B 146.2 (#70 of 148). The confidence ranges of the top two overlap (146.5–149.3 vs 143.9–148.1), so treat the gap as small. On individual benchmarks: GPQA Diamond — Kimi K2.5 87.6%, Nemotron 3 Ultra 550B A55B 85.4%; OTIS Mock AIME 2024–2025 — Kimi K2.5 92.2%, Nemotron 3 Ultra 550B A55B 86.7%.

Which is better for coding?

There are no published SWE-bench Verified results for Nemotron 3 Ultra 550B A55B yet, so there is no like-for-like coding score. On overall capability, Kimi K2.5 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?

Nemotron 3 Ultra 550B A55B has the largest context window at 1,000,000 tokens, against 262,144 for Kimi K2.5. Maximum output per response: Kimi K2.5 up to 262,144, Nemotron 3 Ultra 550B A55B up to 128,000 tokens.

Which can read images, PDFs, audio or video?

Kimi K2.5 accepts text, images and video; Nemotron 3 Ultra 550B A55B accepts text. Kimi K2.5 handles the widest range of inputs.

Are any of these open source?

Yes, both publish their weights, so you can self-host them.

Which is newer?

Nemotron 3 Ultra 550B A55B is the newest, released Jun 4, 2026. Kimi K2.5 came out Jan 27, 2026. Knowledge cutoff: Kimi K2.5 Jan 2025.

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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