Claude Sonnet 4.5 vs GPT-5.6 Sol
Wins 0 of 8 areas
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Wins 8 of 8 areas
Coding · Agents · Reasoning · Facts · Images and charts · Math · Long documents · Following instructions
GPT-5.6 Sol is the stronger all-rounder.Claude Sonnet 4.5 is cheaper.
Scores updated · 38 tests both models report · How we compare
Where each one wins
Tests won in each of the eight areas we test. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- AgentsCarrying out multi-step tasks on its own06GPT-5.6 Sol6 of 6 tests
- CodingWriting and fixing software05GPT-5.6 Sol5 of 5 tests
- ReasoningHard problems that need careful thinking05GPT-5.6 Sol5 of 5 tests
- Images and chartsUnderstanding pictures, charts and video02GPT-5.6 Sol2 of 2 tests
- MathCompetition and research-level math02GPT-5.6 Sol2 of 2 tests
- FactsGetting facts right instead of making them up12GPT-5.6 Sol2 of 4 tests · 1 tie
- Long documentsFinding answers in very long texts01GPT-5.6 Sol1 of 1 test
- Following instructionsDoing exactly what it is asked01GPT-5.6 Sol1 of 1 test
Long documents and following instructions rest on a single test each.
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.
Claude Sonnet 4.5 costs 25% 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 GPT-5.6 Sol pulls ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+80.6points ahead
- Abstract visual puzzles that people can solveARC-AGI-2+78.9points ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+66.3points ahead
Where Claude Sonnet 4.5 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+43.1points ahead
Every test, side by side
All 38 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-5.6 Sol
- Terminal-Bench 2.1GPT-5.6 Sol by 32.255.888+32.2
- Terminal-Bench HardGPT-5.6 Sol by 30.335.665.9+30.3
- LMArena · WebDevGPT-5.6 Sol by 224 rating points13941618+224 rating
- SWE-bench ProGPT-5.6 Sol by 2143.664.6+21
- SciCodeGPT-5.6 Sol by 11.445.757.1+11.4
AgentsGPT-5.6 Sol
- BrowseCompGPT-5.6 Sol by 66.324.190.4+66.3
- Terminal-Bench 4.0GPT-5.6 Sol by 39.9039.9+39.9
- MCP AtlasGPT-5.6 Sol by 39.843.883.6+39.8
- GDPValGPT-5.6 Sol by 35.120.555.6+35.1
- OSWorld-VerifiedGPT-5.6 Sol by 21.661.483+21.6
- τ-Bench V3 · BankingGPT-5.6 Sol by 19.824.544.3+19.8
ReasoningGPT-5.6 Sol
- ARC-AGI-2GPT-5.6 Sol by 78.913.692.5+78.9
- Humanity's Last ExamGPT-5.6 Sol by 31.717.849.5+31.7
- CritPtGPT-5.6 Sol by 31.21.132.3+31.2
- GPQA DiamondGPT-5.6 Sol by 10.783.494.1+10.7
- SimpleBenchGPT-5.6 Sol by 10.554.364.8+10.5
FactsGPT-5.6 Sol
- AA-Omniscience · Non-hallucinationClaude Sonnet 4.5 by 43.150.97.8+43.1
- SimpleQA VerifiedGPT-5.6 Sol by 3930.769.7+39
- AA-Omniscience · AccuracyGPT-5.6 Sol by 26.532.959.4+26.5
- Vectara HHEM hallucination ratelower is bettertie1212.4tie
Images and chartsGPT-5.6 Sol
- CharXiv (RQ)GPT-5.6 Sol by 18.667.285.8+18.6
- MMMU-ProGPT-5.6 Sol by 14.768.783.4+14.7
MathGPT-5.6 Sol
- FrontierMath Tier 4GPT-5.6 Sol by 80.62.483+80.6
- FrontierMath Tiers 1-3 (v2)GPT-5.6 Sol by 65.223.989.1+65.2
Following instructionsGPT-5.6 Sol
- IFBenchGPT-5.6 Sol by 15.457.372.7+15.4
Other results12 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 Agentic IndexGPT-5.6 Sol by 3317.550.5+33
- ARC-AGI-1GPT-5.6 Sol by 32.863.796.5+32.8
- HLE (with tools)GPT-5.6 Sol by 32.53264.5+32.5
- AA IntelligenceGPT-5.6 Sol by 26.320.747+26.3
- Artificial Analysis Coding IndexGPT-5.6 Sol by 25.352.177.4+25.3
- AA-OmniscienceGPT-5.6 Sol by 22.1-0.122+22.1
- ToolathlonGPT-5.6 Sol by 174158+17
- HealthBenchGPT-5.6 Sol by 12.844.257+12.8
- τ²-Bench Telecom (AA run)GPT-5.6 Sol by 778.185.1+7
- vectara_answer_rateGPT-5.6 Sol by 3.595.699.1+3.5
- vectara_factual_consistencytie8887.6tie
- vectara_avg_summary_lengthtie127.8131.1tie
Questions people ask
Which is better, Claude Sonnet 4.5 or GPT-5.6 Sol?
GPT-5.6 Sol wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. Claude Sonnet 4.5 wins none, but costs 25% less.
Which is better for coding?
GPT-5.6 Sol. It wins 5 of the 5 coding tests both models report; Claude Sonnet 4.5 wins none.
Which is cheaper?
Claude Sonnet 4.5 costs $3.00 per million input tokens and $15.00 per million output tokens; GPT-5.6 Sol costs $4.00 and $20.00. That makes Claude Sonnet 4.5 about 25% cheaper for the same work.
How do you compare the two?
We use the 38 benchmark tests both models have published scores on. The verdict counts the 26 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 12 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.