GPT-5.5 Instant vs GPT-5.6 Sol
Wins 0 of 8 areas
—
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.
Scores updated · 26 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.
- CodingWriting and fixing software03GPT-5.6 Sol3 of 3 tests
- AgentsCarrying out multi-step tasks on its own03GPT-5.6 Sol3 of 3 tests
- ReasoningHard problems that need careful thinking03GPT-5.6 Sol3 of 3 tests
- Images and chartsUnderstanding pictures, charts and video03GPT-5.6 Sol3 of 3 tests
- MathCompetition and research-level math02GPT-5.6 Sol2 of 2 tests
- FactsGetting facts right instead of making them up12GPT-5.6 Sol2 of 3 tests
- 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.
GPT-5.6 Sol costs 31% 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
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+62.8points ahead
- Command-line tasks in a real terminalTerminal-Bench 2.1+53.2points ahead
Where GPT-5.5 Instant pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+26.9points ahead
Every test, side by side
All 26 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 53.234.888+53.2
- Terminal-Bench HardGPT-5.6 Sol by 23.542.465.9+23.5
- SciCodeGPT-5.6 Sol by 4.652.557.1+4.6
AgentsGPT-5.6 Sol
- GDPValGPT-5.6 Sol by 55.6055.6+55.6
- τ-Bench V3 · BankingGPT-5.6 Sol by 32.511.844.3+32.5
- Terminal-Bench 4.0GPT-5.6 Sol by 27.312.639.9+27.3
ReasoningGPT-5.6 Sol
- CritPtGPT-5.6 Sol by 29.72.632.3+29.7
- Humanity's Last ExamGPT-5.6 Sol by 27.921.649.5+27.9
- GPQA DiamondGPT-5.6 Sol by 9.584.694.1+9.5
FactsGPT-5.6 Sol
- SimpleQA VerifiedGPT-5.6 Sol by 31.73869.7+31.7
- AA-Omniscience · Non-hallucinationGPT-5.5 Instant by 26.934.77.8+26.9
- AA-Omniscience · AccuracyGPT-5.6 Sol by 13.146.359.4+13.1
Images and chartsGPT-5.6 Sol
- MMMU-ProGPT-5.6 Sol by 7.47683.4+7.4
- CharXiv (RQ)GPT-5.6 Sol by 4.281.685.8+4.2
- LMArena · VisionGPT-5.6 Sol by 29 rating points12501279+29 rating
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 62.826.389.1+62.8
Following instructionsGPT-5.6 Sol
- IFBenchGPT-5.6 Sol by 1.271.572.7+1.2
Other results7 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.
- Artificial Analysis Coding IndexGPT-5.6 Sol by 3839.477.4+38
- τ²-Bench Telecom (AA run)GPT-5.6 Sol by 35.749.485.1+35.7
- AA Agentic IndexGPT-5.6 Sol by 31.319.250.5+31.3
- AA IntelligenceGPT-5.6 Sol by 24.322.747+24.3
- HealthBench ProfessionalGPT-5.6 Sol by 22.138.460.5+22.1
- AA-OmniscienceGPT-5.6 Sol by 10.811.222+10.8
- HealthBenchGPT-5.6 Sol by 5.651.457+5.6
Questions people ask
Which is better, GPT-5.5 Instant 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. GPT-5.5 Instant wins none.
Which is better for coding?
GPT-5.6 Sol. It wins 3 of the 3 coding tests both models report; GPT-5.5 Instant wins none.
Which is cheaper?
GPT-5.5 Instant costs $5.00 per million input tokens and $30.00 per million output tokens; GPT-5.6 Sol costs $4.00 and $20.00. That makes GPT-5.6 Sol about 31% cheaper for the same work.
How do you compare the two?
We use the 26 benchmark tests both models have published scores on. The verdict counts the 19 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 7 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.