GPT-5.5 Instant (June 2026) vs Mercury 2.5
Which is better for the money: GPT-5.5 Instant (June 2026) 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-5.5 Instant (June 2026) scores 13.7 points higher (26.0 vs 12.3) but costs 5.2× as much to run the benchmark ($987 vs $189; premium vs mid-range cost classes). They are not alternatives at one budget: pick GPT-5.5 Instant (June 2026) when you need intelligence above 12.3, and Mercury 2.5 when 12.3 is enough.
| Metric | GPT-5.5 Instant (June 2026) | Mercury 2.5 | Difference |
|---|---|---|---|
| Intelligence (higher is better) | 26.0 | 12.3 | −52.7% Mercury 2.5 is 52.7% less intelligent |
| Total AA cost (lower is better) | $986.85 | $189.17 | −80.8% Mercury 2.5 is 80.8% cheaper |
| End-to-end time (lower is better) | 16.68s | 4.14s | −75.2% Mercury 2.5 is 75.2% faster |
| Price per 1M tokens (in / out) | $5.00 / $30.0 | $0.25 / $0.75 | |
| Input modalities | Text, Image | Text |
Mercury 2.5 vs GPT-5.5 Instant (June 2026): 52.7% less intelligence, 80.8% less cost to run the AA benchmark, and 75.2% faster end-to-end.
Today's Pareto frontier
Against the frontier
- GPT-5.5 Instant (June 2026) is off the frontier: at the same or lower cost, GPT-6.1 Sol (Xhigh) scores 51.00 for $662.
- Mercury 2.5 is off the frontier: at the same or lower cost, GPT-6.1 Terra (Medium) scores 41.30 for $175.
GPT-5.5 Instant (June 2026)Mercury 2.5Today's Pareto frontierEvery other model
Matchup
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Accept: text/markdown or ?format=md returns this page as Markdown. JSON: /api/v1/compare/gpt-5-5-instant-06-26/mercury-2-5 · Markdown: /api/v1/compare/gpt-5-5-instant-06-26/mercury-2-5?format=md · llms.txt · agent skill