GPT-5.6 Terra (Medium) vs Mercury 2.5
Which is better for the money: GPT-5.6 Terra (Medium) by OpenAI or Mercury 2.5 by Inception? Intelligence, total benchmark cost, and end-to-end time from Artificial Analysis & other sources, snapshot 2026-10-26.
Trade-off
Verdict
Depends on your budget
GPT-5.6 Terra (Medium) scores 17.8 points higher (30.1 vs 12.3) but costs 2.0× as much to run the benchmark ($447 vs $218; both mid-range class). Pick GPT-5.6 Terra (Medium) when the extra intelligence is worth the premium, otherwise Mercury 2.5.
| Metric | GPT-5.6 Terra (Medium) | Mercury 2.5 | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 30.1 | 12.3 | −59.1% Mercury 2.5 is 59.1% less intelligent |
| Total AA cost (lower is better) | $446.53 | $218.11 | −51.2% Mercury 2.5 is 51.2% cheaper |
| End-to-end time (lower is better) | 5.84s | 4.18s | −28.4% Mercury 2.5 is 28.4% faster |
| Price per 1M tokens (in / out) | $2.00 / $12.0 | $0.25 / $0.75 | |
| Input modalities | Text, Image | Text |
Mercury 2.5 vs GPT-5.6 Terra (Medium): 59.1% less intelligence, 51.2% less cost to run the AA benchmark, and 28.4% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.6 Terra (Medium) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Medium) scores 47.80 for $361.
- Mercury 2.5 is off the frontier: at the same or lower cost, MiMo-V2.6-Pro scores 46.30 for $207.
GPT-5.6 Terra (Medium)Mercury 2.5Today's Pareto frontierEvery other model
Matchup
Compare something else
Agents:
Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/gpt-5-6-terra-medium/mercury-2-5 · Markdown: /api/v1/compare/gpt-5-6-terra-medium/mercury-2-5?format=md · llms.txt · agent skill