Claude Sonnet 4 vs gpt-oss-120b
Wins 4 of 6 areas
Coding · Agents · Facts · Long documents
Wins 0 of 6 areas
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Claude Sonnet 4 is the stronger all-rounder.gpt-oss-120b is cheaper.
Scores updated · 33 tests both models report · How we compare
Where each one wins
Tests won in each of the six areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- CodingWriting and fixing software40Claude Sonnet 44 of 4 tests
- FactsGetting facts right instead of making them up20Claude Sonnet 42 of 3 tests · 1 tie
- AgentsCarrying out multi-step tasks on its own20Claude Sonnet 42 of 2 tests
- Long documentsFinding answers in very long texts10Claude Sonnet 41 of 1 test
- ReasoningHard problems that need careful thinking11Even1 each · 2 ties
- Following instructionsDoing exactly what it is asked11Even1 each
Long documents rests on a single test.
What it costs
Prices per million tokens, roughly 750,000 words. The bars show the cost of a million tokens read plus a million written.
gpt-oss-120b costs 96% less for the same work.
The biggest differences
The tests each model wins by the widest margin, up to three each. Scores are out of 100.
Where Claude Sonnet 4 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+61.7points ahead
- Long, multi-file coding tasks in real codebasesSWE-bench Pro+26.5points ahead
- Common-sense trick questionsSimpleBench+23.4points ahead
Where gpt-oss-120b pulls ahead
- Follows unfamiliar, precisely checkable instructionsIFBench+14.3points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+8.9points ahead
Every test, side by side
All 33 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingClaude Sonnet 4
- SWE-bench ProClaude Sonnet 4 by 26.542.716.2+26.5
- Terminal-Bench 2.1Claude Sonnet 4 by 10.136.326.2+10.1
- Terminal-Bench HardClaude Sonnet 4 by 7.631.123.5+7.6
- SciCodeClaude Sonnet 4 by 64034+6
AgentsClaude Sonnet 4
- GDPValClaude Sonnet 4 by 4.19.75.6+4.1
- τ-Bench V3 · BankingClaude Sonnet 4 by 3.916.712.8+3.9
ReasoningEven
- SimpleBenchClaude Sonnet 4 by 23.445.522.1+23.4
- Humanity's Last Examgpt-oss-120b by 8.910.719.6+8.9
- CritPttie0.31.1tie
- GPQA Diamondtie77.778.2tie
FactsClaude Sonnet 4
- AA-Omniscience · Non-hallucinationClaude Sonnet 4 by 61.770.99.2+61.7
- Vectara HHEM hallucination ratelower is betterClaude Sonnet 4 by 3.910.314.2+3.9
- AA-Omniscience · Accuracytie22.721.8tie
Following instructionsEven
- IFBenchgpt-oss-120b by 14.354.769+14.3
- Multi-ChallengeClaude Sonnet 4 by 11.857.145.3+11.8
Other results17 tests, not counted
Tests outside the eight areas. They are not counted above: several are summary scores built from other tests, or the same test under another name.
- AA-OmniscienceClaude Sonnet 4 by 49.40.2-49.3+49.4
- Aider-PolyglotClaude Sonnet 4 by 28.970.741.8+28.9
- AIME 2025gpt-oss-120b by 19.570.590+19.5
- TAU-bench (retail)Claude Sonnet 4 by 12.780.567.8+12.7
- AA Agentic IndexClaude Sonnet 4 by 11.417.66.2+11.4
- AA IntelligenceClaude Sonnet 4 by 7.318.911.6+7.3
- Artificial Analysis Coding IndexClaude Sonnet 4 by 7.237.630.4+7.2
- vectara_factual_consistencyClaude Sonnet 4 by 3.989.785.8+3.9
- XSTestClaude Sonnet 4 by 3.996.692.7+3.9
- HarmBenchgpt-oss-120b by 298100+2
- bbqgpt-oss-120b by 1.996.698.5+1.9
- vectara_answer_rategpt-oss-120b by 1.398.699.9+1.3
- τ²-Bench Telecom (AA run)gpt-oss-120b by 1.264.665.8+1.2
- vectara_avg_summary_lengthClaude Sonnet 4 by 10.6 rating points145.8135.2+10.6 rating
- AIR-Bench 2024tie88.388tie
- anthropic_red_teamtie99.299.5tie
- simple_safety_teststie100100tie
Questions people ask
Which is better, Claude Sonnet 4 or gpt-oss-120b?
Claude Sonnet 4 wins four of the six areas where both have results: coding, agents, facts and long documents. gpt-oss-120b wins none, but costs 96% less. They are level on reasoning and following instructions.
Which is better for coding?
Claude Sonnet 4. It wins 4 of the 4 coding tests both models report; gpt-oss-120b wins none.
Which is cheaper?
Claude Sonnet 4 costs $3.00 per million input tokens and $15.00 per million output tokens; gpt-oss-120b costs $0.15 and $0.59. That makes gpt-oss-120b about 96% cheaper for the same work.
How do you compare the two?
We use the 33 benchmark tests both models have published scores on. The verdict counts the 16 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 17 are listed but not counted, because several are summary scores or repeat a test. Each score is the one shown on the model's own page.