Claude 3.5 Sonnet vs o3
Head-to-head comparison across 1benchmark categories. Overall scores shown here use BenchLM's provisional ranking lane.
Verdict
o3 leads for most workloads.
Based on BenchLM composite scores, July 2026.
Claude 3.5 Sonnet
39
o3
54
Pick o3 if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
Category Radar
Head-to-Head by Category
Category Breakdown
| Benchmark | Claude 3.5 Sonnet | Δ | o3 |
|---|---|---|---|
| Math | 1.6 | → 12.9 | 14.5 |
| Coding | 49.0 | — | — |
| Knowledge | 59.4 | — | — |
Operational Comparison
Claude 3.5 Sonnet
o3
$3 / $15
$2 / $8
N/A
118 t/s
N/A
5.38s
200K
200K
Quick Verdict
Pick o3 if you want the stronger benchmark profile. Claude 3.5 Sonnet only becomes the better choice if you would rather avoid the extra latency and token burn of a reasoning model.
o3 is clearly ahead on the provisional aggregate, 54 to 39. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.
o3's sharpest advantage is in mathematics, where it averages 14.5 against 1.6. The single biggest benchmark swing on the page is FrontierMath v2 (Tiers 1-3), 2.069% to 18.685%.
Claude 3.5 Sonnet is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $2.00 input / $8.00 output per 1M tokens for o3. o3 is the reasoning model in the pair, while Claude 3.5 Sonnet is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.
Benchmark Deep Dive
Frequently Asked Questions (2)
Which is better, Claude 3.5 Sonnet or o3?
o3 is ahead on BenchLM's provisional leaderboard, 54 to 39. The biggest single separator in this matchup is FrontierMath v2 (Tiers 1-3), where the scores are 2.069% and 18.685%.
Which is better for math, Claude 3.5 Sonnet or o3?
o3 has the edge for math in this comparison, averaging 14.5 versus 1.6. Inside this category, FrontierMath v2 (Tiers 1-3) is the benchmark that creates the most daylight between them.
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