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K2 Horizon 7B vs Mercury 3

Mercury 3 leads the LLM Stats Score 35.9 to 25.7.

Institute of Foundation Models · Inception · Updated for 2026

Which is better?

Mercury 3 leads the overall LLM Stats Score 35.9 to 25.7, ranking #103 overall.

In the 2 individual benchmarks reported for both models, Mercury 3 wins 2; this is a narrower head-to-head signal than the composite indexes.

Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.

Choose K2 Horizon 7B

  • you need open weights you can self-host or fine-tune

Choose Mercury 3

  • overall performance matters — it scores 35.9 and ranks #103 on LLM Stats
  • your work emphasizes reasoning and coding — it leads those capability indexes
  • you value its reported benchmark strengths — it wins 2 of 2 exact shared results
  • you want the most recent training data — it shipped Oct 2026

At a glance

The differences that matter most.

Core performance indexes
25.7
#184
35.9
#103
25.6
#181
34.6
#108
8.4
#209
21.7
#107
12.0
#133
19.3
#90
Cost, coverage & limits
Benchmark wins
0 of 2
2 of 2
Input price
— / M
$0.10 / M
Output price
— / M
$0.35 / M
Context window
—
1,000,000

Individual benchmarks

8 reported for K2 Horizon 7B · 12 for Mercury 3

2 shared

K2 Horizon 7B outperforms in 0 benchmarks, while Mercury 3 is better at 2 benchmarks (AA-LCR, Tau3 Banking).

Mercury 3 significantly outperforms across most benchmarks.

Fri Oct 30 2026 • llm-stats.com

Human preference

Blind head-to-head votes and playground preference scores

Context Window

Maximum input and output token capacity

Only Mercury 3 specifies input context (1,000,000 tokens). Only Mercury 3 specifies output context (131,072 tokens).

Institute of Foundation Models
K2 Horizon 7B
Input- tokens
Output- tokens
Inception
Mercury 3
Input1,000,000 tokens
Output131,072 tokens
Fri Oct 30 2026 • llm-stats.com

License

Usage and distribution terms

K2 Horizon 7B is licensed under Apache 2.0, while Mercury 3 uses a proprietary license.

License differences may affect how you can use these models in commercial or open-source projects.

K2 Horizon 7B

Apache 2.0

Open weights

Mercury 3

Proprietary

Closed source

Release Timeline

When each model was launched

K2 Horizon 7B was released on 2026-09-03, while Mercury 3 was released on 2026-10-19.

Mercury 3 is 2 months newer than K2 Horizon 7B.

K2 Horizon 7B

Sep 3, 2026

1 months ago

Mercury 3

Oct 19, 2026

1 weeks ago

1mo newer

Knowledge Cutoff

When training data ends

Neither model specifies a knowledge cutoff date.

Unable to compare the recency of their training data.

No cutoff dates available

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against K2 Horizon 7B and Mercury 3 side-by-side, then vote on the output you prefer.

K2 Horizon 7B
✓ Preferred
Mercury 3
Open in Playground

FAQ

Common questions about K2 Horizon 7B vs Mercury 3.

Which is better, K2 Horizon 7B or Mercury 3?

Mercury 3 leads the LLM Stats Score 35.9 to 25.7. K2 Horizon 7B is made by Institute of Foundation Models and Mercury 3 is made by Inception. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does K2 Horizon 7B compare to Mercury 3 in benchmarks?

K2 Horizon 7B scores HMMT Feb 26: 73.3%, SWE-Bench Verified: 70.6%, AA-LCR: 68.0%, BrowseComp: 59.0%, Terminal-Bench 2.1: 39.1%. Mercury 3 scores GPQA: 89.2%, AA-LCR: 77.7%, IFBench: 76.8%, MRCR v2: 75.5%, DeepSearchQA: 71.3%.

What are the context window sizes for K2 Horizon 7B and Mercury 3?

K2 Horizon 7B supports an unknown number of tokens and Mercury 3 supports 1.0M tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between K2 Horizon 7B and Mercury 3?

Key differences include LLM Stats Score (25.7 vs 35.9), licensing (Apache 2.0 vs Proprietary). See the full comparison above for benchmark-by-benchmark results.

Who makes K2 Horizon 7B and Mercury 3?

K2 Horizon 7B is developed by Institute of Foundation Models and Mercury 3 is developed by Inception.