Model comparison
GPT-5.1 vs o3
Head-to-head evidence from 15 shared benchmark results across 7 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.1 #94 (Estimated); o3 #131 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.1 and o3 share 15 comparable benchmark results. 1 of 8 categories are comparable. 6 results are unique to GPT-5.1; 1 to o3.
Updated July 20, 2026- Shared results
- 15
- GPT-5.1 only
- 6
- o3 only
- 1
- Comparable categories
- 1 / 8
Pick GPT-5.1 if you want the stronger benchmark profile. o3 only becomes the better choice if you want the cheaper token bill.
Confidence note. This is a partial-evidence comparison with 15 shared benchmark results across 7 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
GPT-5.1 is clearly ahead on the BenchAlign aggregate, 53.65 to 47.89. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
GPT-5.1's sharpest advantage is in mathematics, where it averages 26.4 against 14.5. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 31.034% to 18.685%.
GPT-5.1 is also the more expensive model on tokens at $1.25 input / $10.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for o3.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | GPT-5.1 | Δ | o3 |
|---|---|---|---|
| Math | GPT-5.126.4 | Margin← 11.9 | o314.5 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
FrontierMath v2 (Tiers 1-3)
MathA 31.034%B 18.685%Winner: GPT-5.1Δ 12.3FrontierMath v2 (Tiers 1-3): GPT-5.1 scored 31.034%; o3 scored 18.685%. GPT-5.1 wins this benchmark. - Source ↗
FrontierMath v2 (Tier 4)
MathA 12.500%B 2.083%Winner: GPT-5.1Δ 10.4FrontierMath v2 (Tier 4): GPT-5.1 scored 12.500%; o3 scored 2.083%. GPT-5.1 wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.1 | o3 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.1$1.25 input / $10 output | o3$2 input / $8 output | o3 has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.1111 tok/s | o3118 tok/s | o3 has the higher measured throughput. |
| First-answer latencyseconds to first token | GPT-5.157.47 s | o35.38 s | o3 reaches the first token sooner. |
| Context windowmaximum listed tokens | GPT-5.1200K | o3200K | Listed context windows are equal. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding3 benchmarks
Reasoning2 benchmarks
Knowledge6 benchmarks
| Benchmark | GPT-5.1 | o3 | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 36.9% | 30.4% | GPT-5.1 leads |
| AA-GPQA DiamondSource | 87.3% | 82.7% | GPT-5.1 leads |
| AA-HLESource | 26.5% | 20.0% | GPT-5.1 leads |
| AA-Omniscience IndexSource | 5.6% | -15.3% | GPT-5.1 leads |
| AA-Omniscience AccuracySource | 37.6% | 38.4% | o3 leads |
| AA-Omniscience Hallucination RateSource | 51.3% | 87.1% | GPT-5.1 leads |
MathGPT-5.1 wins3 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.1 | o3 | Result |
|---|---|---|---|
| AA-IFBenchSource | 72.9% | 71.4% | GPT-5.1 leads |
Frequently Asked Questions (2)
Which is better, GPT-5.1 or o3?
GPT-5.1 is ahead on BenchLM's BenchAlign leaderboard, 53.65 to 47.89. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 31.034% and 18.685%.
Which is better for math, GPT-5.1 or o3?
GPT-5.1 has the edge for math in this comparison, averaging 26.4 versus 14.5. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.
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