Model comparison
Mercury 2.5 vs o3-pro
o3-pro is the stronger model overall, scoring 42.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 519× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Last verified . 0 shared benchmarks.
Summary
- The widest gap is in coding, where o3-pro leads 55.5 to 39.5.
- Mercury 2.5 is cheaper at $0.04 / $0.15 per million input/output tokens, against $20 / $80 for o3-pro.
- Mercury 2.5 accepts more context: 260K tokens versus 200K.
Side by side
| Mercury 2.5 | o3-pro | |
|---|---|---|
| Provider | Inception | OpenAI |
| Noometry Index | 33.5 | 42.9 |
| Released | 2026-09-08 | 2025-06-10 |
| Weights | Proprietary | Proprietary |
| Context window | 260K | 200K |
| Max output | 66K | 100K |
| Input $ / M tokens | $0.04 | $20 |
| Output $ / M tokens | $0.15 | $80 |
| Results tracked | 4 | 12 |
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Category by category
Coding o3-pro leads
Mercury 2.5: 39.5 (#156), o3-pro: 55.5 (#24)
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| Aider Polyglot | — | 84.9% |
| SciCode | 38.5% | — |
| WeirdML | — | 58.2% |
| ALE-Bench | 301.65 | — |
Reasoning o3-pro leads
Mercury 2.5: 22.4 (#193), o3-pro: 23.8 (#171)
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| ARC-AGI-2 | — | 4.9% |
| Kagi LLM Benchmark | — | 72.1% |
| ARC-AGI-1 | — | 59.3% |
| CritPt | 0% | — |
| DTBench | — | 86.9% |
| LMCA | — | 38.5% |
| Epoch Capabilities Index | — | 147.42 |
Math Not comparable
Mercury 2.5: 23.3 (#272), o3-pro: —
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| ProofBench | 3% | — |
Knowledge Not comparable
Mercury 2.5: —, o3-pro: 29.5 (#238)
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| Confabulations | — | 14.2% |
| Vectara Hallucination Rate | — | 23.3% |
Long Context Not comparable
Mercury 2.5: —, o3-pro: 72.2 (#1)
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| Fiction.LiveBench | — | 97.2% |
Writing & Preference Not comparable
Mercury 2.5: —, o3-pro: 57.1 (#133)
| Benchmark | Mercury 2.5 | o3-pro |
|---|---|---|
| Short-Story Creative Writing | — | 84.4% |
Frequently asked questions
Is Mercury 2.5 better than o3-pro?
o3-pro is the stronger model overall, scoring 42.9 to 33.5 on the Noometry Index. Mercury 2.5 costs 519× less per token, which makes it the better buy when o3-pro's lead doesn't matter for your workload.
Which is cheaper, Mercury 2.5 or o3-pro?
Mercury 2.5 is cheaper. It lists at $0.04 per million input tokens and $0.15 per million output tokens; o3-pro lists at $20 and $80.
Is Mercury 2.5 or o3-pro better for coding?
o3-pro scores higher on coding benchmarks: 55.5 versus 39.5 in the Noometry coding category.
Which has the bigger context window?
Mercury 2.5 does, with 260K tokens against 200K.
How many benchmarks do Mercury 2.5 and o3-pro share?
0 benchmarks have published results for both models. Mercury 2.5 has 4 scored results on Noometry and o3-pro has 12.