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Model comparison

Kimi K3 vs Mistral Medium 3.5

Moonshot AI against Mistral, compared on context, price, and verified benchmark results.

Catalog record checked September 26, 2026Individual provider fields may changeEvidence confidence: High — see receipts below

Moonshot AI

Kimi K3

Frontier · Open weights

vs

Mistral

Mistral Medium 3.5

Frontier · Open weights

AI model capability comparison
SpecificationKimi K3Mistral Medium 3.5
ProviderMoonshot AIMistral
TierFrontierFrontier
Context windowWinner: 1.05M262K
Max output1.05MNot verifiedUnverified
Input / 1M tokens$3Winner: $1.50
Output / 1M tokens$15Winner: $7.50
WeightsOpenOpen
Parameters2.8T (open-weight MoE)128B dense
Reasoning levelslow, high, maxNot verifiedUnverified
Modalitiestext, image, videotext, image
LicenseNot disclosedUnverifiedModified MIT
API model idkimi-k3mistral-medium-3-5
ReleasedJuly 16, 2026April 28, 2026
Artificial Analysis Intelligence Index [max] (2026-09-26)43.6Not verifiedUnverified
Artificial Analysis Intelligence Index (2026-09-26)Not verifiedUnverified14.2
Terminal-Bench 2.1 (2026-07-27)88.3Not verifiedUnverified
GPQA Diamond (2026-07-27)93.5Not verifiedUnverified
Humanity's Last Exam (2026-07-27)56Not verifiedUnverified
SWE-bench Verified (2026-09-01)93.4Not verifiedUnverified

Prices are USD per million tokens at standard rates, excluding batch and caching discounts. Bold indicates the better figure where one is objectively better. Values we could not confirm from the provider are shown as “Not verified” rather than estimated.

Benchmark receipts

Where each score comes from, and how far it can be compared across models.

Pricing tiers

Kimi K3: $3/$15 per MTok; cached input $0.30/MTok. max_completion_tokens can be set up to 1,048,576 (default 131,072). Open-weight under the custom Kimi K3 License (not a standard open-source licence). 2.8T MoE with native vision.

Mistral Medium 3.5: Mistral first-party API $1.50/$7.50 per MTok; Mistral advertises up to 90% off cached input (exact cached rate not verified). Open weights under a Modified MIT licence. 128B dense.

FrontierOpen weightsRecord checked September 26, 2026

Kimi K3

Kimi K3 is Moonshot AI's open-weight frontier model — 2.8T MoE, 1M context, tied near the top of open-weight leaderboards.

Best for

  • Open-weight frontier work
  • Long-context
  • Multimodal

Watch out

Self-hosting needs large clusters; hosted rates vary.

FrontierOpen weightsRecord checked September 26, 2026

Mistral Medium 3.5

Mistral Medium 3.5 is the model Mistral calls its new flagship — a 128B dense open-weight model with a 256K context, powering its Vibe remote agents.

Best for

  • EU-hosted frontier work
  • Open-weight self-hosting
  • Mistral Vibe agents

Watch out

Far behind US and Chinese frontier models on the Artificial Analysis index; max output is not published. Check the Modified MIT terms before redistribution.

When the cheaper one wins

Mistral Medium 3.5 is cheaper on output at $7.50 per million tokens against $15 for Kimi K3 — about 2.0×. Use the cheaper tier for classification, extraction, summarisation, and any task where the expensive model’s extra score does not change the accepted output. The expensive one only pays if your hardest task actually fails on the cheap tier. These are standard-tier API rates, excluding batch and cache discounts.

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Evidence confidence: High

How strong and complete the evidence behind this comparison is — not a prediction of which model is better.

  • Pricing verified on both sides — Input and output rates are verified for both models.
  • 3/5 core specs verified on both sides — Not published for at least one side: max output, reasoning levels.
  • 1 shared named benchmark with differing scores — Measured on: Artificial Analysis Intelligence Index.
  • Verified within the last 90 days — Newest catalog check was 2 days ago.
  • Both models carry source citations — Each side has at least two catalog sources on record.

Source receipts

Each catalog figure was checked against the provider or an independent second source on the date shown.

Related comparisons

Diving deeper on one model? Kimi K3 · Mistral Medium 3.5

Common questions

Kimi K3 vs Mistral Medium 3.5

Answered from the verified figures on this page rather than general guidance.

Is Kimi K3 or Mistral Medium 3.5 cheaper for input?
Mistral Medium 3.5 is cheaper at $1.50 per million input tokens, against $3 for Kimi K3 — roughly 2.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Kimi K3 has tiered pricing: $3/$15 per MTok; cached input $0.30/MTok. max_completion_tokens can be set up to 1,048,576 (default 131,072). Open-weight under the custom Kimi K3 License (not a standard open-source licence). 2.8T MoE with native vision. Mistral Medium 3.5 has tiered pricing: Mistral first-party API $1.50/$7.50 per MTok; Mistral advertises up to 90% off cached input (exact cached rate not verified). Open weights under a Modified MIT licence. 128B dense.
Is Kimi K3 or Mistral Medium 3.5 cheaper for output?
Mistral Medium 3.5 is cheaper at $7.50 per million output tokens, against $15 for Kimi K3 — roughly 2.0× the price. Output tokens usually dominate a real bill, so weigh the output rate more heavily than the input rate. These are base rates; Kimi K3 has tiered pricing: $3/$15 per MTok; cached input $0.30/MTok. max_completion_tokens can be set up to 1,048,576 (default 131,072). Open-weight under the custom Kimi K3 License (not a standard open-source licence). 2.8T MoE with native vision. Mistral Medium 3.5 has tiered pricing: Mistral first-party API $1.50/$7.50 per MTok; Mistral advertises up to 90% off cached input (exact cached rate not verified). Open weights under a Modified MIT licence. 128B dense.
Which has the larger context window, Kimi K3 or Mistral Medium 3.5?
Kimi K3 accepts 1.05M tokens against 262K for Mistral Medium 3.5. This only matters if you routinely send very long documents or large codebases.
Should I use Kimi K3 or Mistral Medium 3.5?
Both sit in the frontier tier, so the choice usually comes down to price and context rather than capability. Kimi K3 suits open-weight frontier work; Mistral Medium 3.5 suits eu-hosted frontier work.

Next step

Choosing between them

The verified figures that separate this pair, computed from the catalog rather than restated boilerplate.

  • Input price: Mistral Medium 3.5 costs $1.50 per 1M tokens versus $3 for Kimi K3 — a 2x difference at the headline tier.
  • Context: Kimi K3 takes 1.05M against 262K for Mistral Medium 3.5 — only decisive if your prompts approach the smaller window.
  • Measured capability: Kimi K3 leads Artificial Analysis Intelligence Index 43.6 to 14.2 (measured 2026-09-26).
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