GPT-5.6 Luna vs GPT-6.1 Sol
Wins 0 of 8 areas
—
Wins 7 of 8 areas
Coding · Agents · Reasoning · Facts · Images and charts · Math · Following instructions
GPT-6.1 Sol is the stronger all-rounder.GPT-5.6 Luna is cheaper.
Scores updated · 39 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.
- ReasoningHard problems that need careful thinking06GPT-6.1 Sol6 of 6 tests
- AgentsCarrying out multi-step tasks on its own03GPT-6.1 Sol3 of 3 tests
- FactsGetting facts right instead of making them up03GPT-6.1 Sol3 of 3 tests
- MathCompetition and research-level math03GPT-6.1 Sol3 of 3 tests
- Images and chartsUnderstanding pictures, charts and video02GPT-6.1 Sol2 of 2 tests
- CodingWriting and fixing software12GPT-6.1 Sol2 of 4 tests · 1 tie
- Following instructionsDoing exactly what it is asked01GPT-6.1 Sol1 of 1 test
- Long documentsFinding answers in very long texts00Even0 each · 1 tie
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.
GPT-5.6 Luna costs 88% 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-6.1 Sol pulls ahead
- Solves new puzzle games it has never seenARC-AGI-3+52.5points ahead
- Complex command-line tasks across many fieldsTerminal-Bench 4.0+44.5points ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+41.5points ahead
Where GPT-5.6 Luna pulls ahead
- Programming problems, refreshed regularlyLiveBench · Coding+2.5points ahead
Every test, side by side
All 39 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-6.1 Sol
- LMArena · WebDevGPT-6.1 Sol by 224 rating points15191743+224 rating
- LiveBench · Agentic CodingGPT-6.1 Sol by 6.248.454.5+6.2
- LiveBench · CodingGPT-5.6 Luna by 2.582.980.4+2.5
- SciCodetie53.654.2tie
AgentsGPT-6.1 Sol
- Terminal-Bench 4.0GPT-6.1 Sol by 44.511.656.1+44.5
- AA ApexAgentsGPT-6.1 Sol by 24.235.860+24.2
- GDPValGPT-6.1 Sol by 6.74854.7+6.7
ReasoningGPT-6.1 Sol
- ARC-AGI-3GPT-6.1 Sol by 52.50.252.7+52.5
- SimpleBenchGPT-6.1 Sol by 36.146.882.9+36.1
- ARC-AGI-2GPT-6.1 Sol by 34.659.694.2+34.6
- Humanity's Last ExamGPT-6.1 Sol by 13.439.552.9+13.4
- CritPtGPT-6.1 Sol by 11.120.631.7+11.1
- LiveBench · ReasoningGPT-6.1 Sol by 785.692.6+7
FactsGPT-6.1 Sol
- AA-Omniscience · Non-hallucinationGPT-6.1 Sol by 38.37.445.7+38.3
- SimpleQA VerifiedGPT-6.1 Sol by 32.94173.9+32.9
- AA-Omniscience · AccuracyGPT-6.1 Sol by 19.442.762.1+19.4
Images and chartsGPT-6.1 Sol
- MMMU-ProGPT-6.1 Sol by 7.478.686+7.4
- LMArena · VisionGPT-6.1 Sol by 30 rating points12561286+30 rating
MathGPT-6.1 Sol
- FrontierMath Tier 4GPT-6.1 Sol by 41.558.5100+41.5
- FrontierMath Tiers 1-3 (v2)GPT-6.1 Sol by 11.682.193.7+11.6
- LiveBench · MathematicsGPT-6.1 Sol by 9.687.296.8+9.6
Following instructionsGPT-6.1 Sol
- LiveBench · Instruction FollowingGPT-6.1 Sol by 14.160.174.2+14.1
Other results16 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-OmniscienceGPT-6.1 Sol by 51.8-10.341.5+51.8
- Terminal-Bench 4.0GPT-6.1 Sol by 40.917.358.2+40.9
- OSWorld 2.0GPT-6.1 Sol by 25.845.671.4+25.8
- livebench_languageGPT-6.1 Sol by 17.572.690.1+17.5
- AA IntelligenceGPT-6.1 Sol by 14.537.351.8+14.5
- HealthBench ProfessionalGPT-6.1 Sol by 9.455.765.1+9.4
- HealthBench Professional length-adjustedGPT-6.1 Sol by 8.555.764.2+8.5
- GDP (Surge AI)GPT-6.1 Sol by 8.322.731+8.3
- DeepSWE 1.1GPT-6.1 Sol by 8.26775.2+8.2
- ARC-AGI-1GPT-6.1 Sol by 5.890.796.5+5.8
- livebench_data_analysisGPT-6.1 Sol by 4.77882.7+4.7
- HealthBench HardGPT-6.1 Sol by 4.23236.2+4.2
- HealthBench Hard length-adjustedGPT-6.1 Sol by 4.23236.2+4.2
- HealthBenchGPT-6.1 Sol by 2.755.858.5+2.7
- HealthBench length-adjustedGPT-6.1 Sol by 2.755.858.5+2.7
- HealthBench Consensus length-adjustedtie95.196tie
Questions people ask
Which is better, GPT-5.6 Luna or GPT-6.1 Sol?
GPT-6.1 Sol wins seven of the eight areas we test: coding, agents, reasoning, facts, images and charts, math and following instructions. GPT-5.6 Luna wins none, but costs 88% less. They are level on long documents.
Which is better for coding?
GPT-6.1 Sol. It wins 2 of the 4 coding tests both models report; GPT-5.6 Luna wins 1, and 1 is a tie.
Which is cheaper?
GPT-5.6 Luna costs $0.20 per million input tokens and $1.20 per million output tokens; GPT-6.1 Sol costs $2.00 and $10.00. That makes GPT-5.6 Luna about 88% cheaper for the same work.
How do you compare the two?
We use the 39 benchmark tests both models have published scores on. The verdict counts the 23 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 16 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.