# GPT-5.1-Codex vs Mercury Voice

> Side-by-side benchmark comparison for GPT-5.1-Codex and Mercury Voice across agentic, coding, multimodal, knowledge, reasoning, multilingual, and math tasks.

- Canonical page: https://benchlm.ai/compare/gpt-5-1-codex-vs-mercury-voice
- Last updated: September 29, 2026

- Shared sourced benchmarks: 0
- HTML indexing: indexable
- Ranking lane: BenchAlign v5.7

## Quick Verdict

No benchmark verdict yet: there is no shared sourced benchmark row for GPT-5.1-Codex and Mercury Voice.

## Summary

- GPT-5.1-Codex and Mercury Voice do not currently share a sourced benchmark row. The mirror therefore compares metadata, pricing, context windows, and each model's separately reported coverage without naming a benchmark winner.

## Model Snapshot

| Property | GPT-5.1-Codex | Mercury Voice |
|----------|----------|----------|
| Creator | OpenAI | Inception |
| Type | Proprietary | Proprietary |
| Reasoning | Reasoning | Reasoning |
| Context | 400K | 128K |
| Independent public score (not head-to-head) | 44.38 | null |
| Benchmarks Covered | 4 | 0 |
| Pricing (input/output) | $1.25 / $10.00 | $0.40 / $1.50 |

## Category Breakdown

### Agentic

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: Coming soon
- Mercury Voice public-lane score: Coming soon

| Benchmark | GPT-5.1-Codex | Mercury Voice | Winner |
|-----------|-----------|-----------|--------|
| Gert Labs | 49.68% | Coming soon | Coming soon |
| JobBench | 26.2% | Coming soon | Coming soon |

### Coding

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 32.7 (Estimated · #85/143)
- Mercury Voice public-lane score: Coming soon

| Benchmark | GPT-5.1-Codex | Mercury Voice | Winner |
|-----------|-----------|-----------|--------|
| Vibe Code Bench | 13.12% | Coming soon | Coming soon |
| LiveCodeBench (Vals) | 85.6% | Coming soon | Coming soon |

### Reasoning

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 69.9 (Unranked · 2 rankable rows)
- Mercury Voice public-lane score: Coming soon

### Multimodal & Grounded

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 67.9 (Unranked · 1 rankable row)
- Mercury Voice public-lane score: Coming soon

### Knowledge

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 48.1 (Estimated · #69/169)
- Mercury Voice public-lane score: Coming soon

### Instruction Following

- Winner: Insufficient shared evidence
- GPT-5.1-Codex public-lane score: 84.2 (#42/124)
- Mercury Voice public-lane score: Coming soon

## FAQ

### Can I compare GPT-5.1-Codex and Mercury Voice on BenchLM yet?

Not fully yet. BenchLM is tracking both models, but sourced benchmark coverage is still incomplete for a fair score-level comparison.

### Why does this page show "coming soon" values?

BenchLM only calls winners when public benchmark coverage is available on both sides of the comparison.

## Related Comparisons

- [GPT-5.1-Codex vs GPT-6 Astra](/compare/gpt-5-1-codex-vs-gpt-6-astra)
- [Mercury Voice vs GPT-6 Astra](/compare/gpt-6-astra-vs-mercury-voice)
- [GPT-5.1-Codex vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-gpt-5-1-codex)
- [Mercury Voice vs Claude Opus 5.5](/compare/claude-opus-5-5-vs-mercury-voice)

## Explore More

- [GPT-5.1-Codex profile](/models/gpt-5-1-codex)
- [Mercury Voice profile](/models/mercury-voice)
- [Compare Pricing](/llm-pricing)
- [Alternative Finder](/tools/alternative-finder)
- [LLM Selector](/tools/llm-selector)
- [Overall Rankings](/best/overall)