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Mercury 3 vs Step 3.7 Flash

Mercury 3 and Step 3.7 Flash are closely matched at 36.1 and 29.7 on the LLM Stats Score. Mercury 3 is 2.7x cheaper per token.

Inception · StepFun · Updated for 2026

Which is better?

Mercury 3 and Step 3.7 Flash are closely matched on the overall LLM Stats Score at 36.1 and 29.7.

On price, Mercury 3 is roughly 2.7x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.

Mercury 3 also accepts a larger context window (1,000,000 input tokens), making it the stronger choice for long documents and large codebases.

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

Choose Mercury 3

  • cost matters — it's about 2.7x cheaper per token
  • you process long inputs — it offers a 1,000,000 token context window
  • you want the most recent training data — it shipped Oct 2026

Choose Step 3.7 Flash

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

At a glance

The differences that matter most.

Mercury 3
Inception
Step 3.7 Flash
StepFun
Core performance indexes
LLM Stats Score
36.1
#98
29.7
#144
Reasoning
34.8
#103
29.8
#141
Coding
21.5
#105
19.0
#125
Agents
19.4
#84
13.1
#116
Cost, coverage & limits
Benchmark wins
—
—
Input price
$0.10 / M
$0.20 / M
Output price
$0.35 / M
$1.15 / M
Context window
1,000,000
262,144

Individual benchmarks

12 reported for Mercury 3 · 4 for Step 3.7 Flash

No common benchmarks found

Mercury 3 and Step 3.7 Flashdon't have any common benchmark datasets to compare. They may have been evaluated on different testing suites.

Human preference

Blind head-to-head votes and playground preference scores

Pricing Analysis

Price comparison per million tokens

Mercury 3 costs less

For input processing, Mercury 3 ($0.10/1M tokens) is 2.0x cheaper than Step 3.7 Flash ($0.20/1M tokens).

For output processing, Mercury 3 ($0.35/1M tokens) is 3.3x cheaper than Step 3.7 Flash ($1.15/1M tokens).

In conclusion, Step 3.7 Flash is more expensive than Mercury 3.*

* Using a 3:1 ratio of input to output tokens

Lowest available price from all providers
Sun Oct 25 2026 • llm-stats.com
Inception
Mercury 3
Input tokens$0.10
Output tokens$0.35
Best providerInception
StepFun
Step 3.7 Flash
Input tokens$0.20
Output tokens$1.15
Best providerDeepinfra
Notice missing or incorrect data?

Context Window

Maximum input and output token capacity

Mercury 3 accepts 1,000,000 input tokens compared to Step 3.7 Flash's 262,144 tokens. Step 3.7 Flash can generate longer responses up to 262,144 tokens, while Mercury 3 is limited to 131,072 tokens.

Inception
Mercury 3
Input1,000,000 tokens
Output131,072 tokens
StepFun
Step 3.7 Flash
Input262,144 tokens
Output262,144 tokens
Sun Oct 25 2026 • llm-stats.com

Input capabilities

Documented input modalities across available providers

Step 3.7 Flash supports multimodal inputs, whereas Mercury 3 does not.

Step 3.7 Flash can handle both text and other forms of data like images, making it suitable for multimodal applications.

Mercury 3

Text
Images
Audio
Video

Step 3.7 Flash

Text
Images
Audio
Video

License

Usage and distribution terms

Mercury 3 is licensed under a proprietary license, while Step 3.7 Flash uses Apache 2.0.

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

Mercury 3

Proprietary

Closed source

Step 3.7 Flash

Apache 2.0

Open weights

Release Timeline

When each model was launched

Mercury 3 was released on 2026-10-19, while Step 3.7 Flash was released on 2026-06-10.

Mercury 3 is 4 months newer than Step 3.7 Flash.

Mercury 3

Oct 19, 2026

6 days ago

4mo newer
Step 3.7 Flash

Jun 10, 2026

4 months ago

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

Provider Availability

Mercury 3 is available from Inception. Step 3.7 Flash is available from DeepInfra.

Mercury 3

inception logo
Inception
Input Price:Input: $0.10/1MOutput Price:Output: $0.35/1M

Step 3.7 Flash

deepinfra logo
Deepinfra
Input Price:Input: $0.20/1MOutput Price:Output: $1.15/1M
* Prices shown are per million tokens

Outputs Comparison

Notice missing or incorrect data?

Judge for yourself.

Run your own prompts against Mercury 3 and Step 3.7 Flash side-by-side, then vote on the output you prefer.

Mercury 3
✓ Preferred
Step 3.7 Flash
Open in Playground

FAQ

Common questions about Mercury 3 vs Step 3.7 Flash.

Which is better, Mercury 3 or Step 3.7 Flash?

Mercury 3 and Step 3.7 Flash are closely matched on the LLM Stats Score at 36.1 and 29.7. Mercury 3 is made by Inception and Step 3.7 Flash is made by StepFun. The best choice depends on your use case — compare their capability indexes, individual benchmarks, pricing, and limits above.

How does Mercury 3 compare to Step 3.7 Flash in benchmarks?

Mercury 3 scores GPQA: 89.2%, AA-LCR: 77.7%, IFBench: 76.8%, MRCR v2: 75.5%, DeepSearchQA: 71.3%. Step 3.7 Flash scores Terminal-Bench 2.1: 59.5%, SWE-Bench Pro: 56.3%, Humanity's Last Exam (with tools, text-only): 47.2%, GDPval: 45.8%.

Is Mercury 3 cheaper than Step 3.7 Flash?

Mercury 3 is 2.0x cheaper for input tokens. Mercury 3 costs $0.10/M input and $0.35/M output via inception. Step 3.7 Flash costs $0.20/M input and $1.15/M output via deepinfra.

What are the context window sizes for Mercury 3 and Step 3.7 Flash?

Mercury 3 supports 1.0M tokens and Step 3.7 Flash supports 262K tokens. A larger context window lets you process longer documents, conversations, or codebases in a single request.

What are the main differences between Mercury 3 and Step 3.7 Flash?

Key differences include LLM Stats Score (36.1 vs 29.7), context window (1.0M vs 262K), input pricing ($0.10 vs $0.20/M), multimodal support (no vs yes), licensing (Proprietary vs Apache 2.0). See the full comparison above for benchmark-by-benchmark results.

Who makes Mercury 3 and Step 3.7 Flash?

Mercury 3 is developed by Inception and Step 3.7 Flash is developed by StepFun.

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