GPT-5.4 vs Mercury 3
GPT-5.4 and Mercury 3 are closely matched at 41.6 and 36.1 on the LLM Stats Score. Mercury 3 is 34.6x cheaper per token.
OpenAI · Inception · Updated for 2026
Which is better?
GPT-5.4 and Mercury 3 are closely matched on the overall LLM Stats Score at 41.6 and 36.1.
In the 1 individual benchmarks reported for both models, GPT-5.4 wins 1; this is a narrower head-to-head signal than the composite indexes.
On price, Mercury 3 is roughly 34.6x cheaper per token on a blended 3:1 input/output basis, which adds up quickly at production volume.
Based on current LLM Stats indexes, shared benchmarks, pricing, and model metadata for 2026.
Choose GPT-5.4
- you value its reported benchmark strengths — it wins 1 of 1 exact shared results
Choose Mercury 3
- cost matters — it's about 34.6x cheaper per token
- you want the most recent training data — it shipped Oct 2026
At a glance
The differences that matter most.
Capability indexes
Additional strengths measured across groups of related public benchmarks
Individual benchmarks
23 reported for GPT-5.4 · 12 for Mercury 3
GPT-5.4 outperforms in 1 benchmarks (GPQA), while Mercury 3 is better at 0 benchmarks.
GPT-5.4 significantly outperforms across most benchmarks.
Human preference
Blind head-to-head votes and playground preference scores
Pricing Analysis
Price comparison per million tokens
For input processing, GPT-5.4 ($2.50/1M tokens) is 25.0x more expensive than Mercury 3 ($0.10/1M tokens).
For output processing, GPT-5.4 ($15.00/1M tokens) is 42.9x more expensive than Mercury 3 ($0.35/1M tokens).
In conclusion, GPT-5.4 is more expensive than Mercury 3.*
* Using a 3:1 ratio of input to output tokens
Context Window
Maximum input and output token capacity
Both models have the same input context window of 1,000,000 tokens. Mercury 3 can generate longer responses up to 131,072 tokens, while GPT-5.4 is limited to 128,000 tokens.
Input capabilities
Documented input modalities across available providers
GPT-5.4 supports multimodal inputs, whereas Mercury 3 does not.
GPT-5.4 can handle both text and other forms of data like images, making it suitable for multimodal applications.
GPT-5.4
Mercury 3
License
Usage and distribution terms
Both models are licensed under proprietary licenses.
Both models have usage restrictions defined by their respective organizations.
Proprietary
Closed source
Proprietary
Closed source
Release Timeline
When each model was launched
GPT-5.4 was released on 2026-03-05, while Mercury 3 was released on 2026-10-19.
Mercury 3 is 8 months newer than GPT-5.4.
Mar 5, 2026
7 months ago
Oct 19, 2026
1 weeks ago
7mo newerKnowledge Cutoff
When training data ends
Neither model specifies a knowledge cutoff date.
Unable to compare the recency of their training data.
Provider Availability
GPT-5.4 is available from OpenAI. Mercury 3 is available from Inception.
GPT-5.4
Mercury 3
Outputs Comparison
Judge for yourself.
Run your own prompts against GPT-5.4 and Mercury 3 side-by-side, then vote on the output you prefer.
FAQ
Common questions about GPT-5.4 vs Mercury 3.