GPT-5.5 vs o1
Wins 8 of 8 areas
Coding · Agents · Reasoning · Facts · Images and charts · Math · Long documents · Following instructions
Wins 0 of 8 areas
—
GPT-5.5 is the stronger all-rounder.
Scores updated · 22 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 thinking40GPT-5.54 of 4 tests
- CodingWriting and fixing software20GPT-5.52 of 2 tests
- Images and chartsUnderstanding pictures, charts and video20GPT-5.52 of 2 tests
- FactsGetting facts right instead of making them up21GPT-5.52 of 3 tests
- AgentsCarrying out multi-step tasks on its own10GPT-5.51 of 1 test
- MathCompetition and research-level math10GPT-5.51 of 1 test
- Long documentsFinding answers in very long texts10GPT-5.51 of 1 test
- Following instructionsDoing exactly what it is asked10GPT-5.51 of 1 test
Agents, math, 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-5.5 costs 53% 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-5.5 pulls ahead
- Unpublished advanced math problemsFrontierMath Tiers 1-3 (v2)+70.6points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+47.7points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+38.8points ahead
Where o1 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+19.4points ahead
Every test, side by side
All 22 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-5.5
- Terminal-Bench HardGPT-5.5 by 47.760.612.9+47.7
- SciCodeGPT-5.5 by 2055.835.8+20
ReasoningGPT-5.5
- Humanity's Last ExamGPT-5.5 by 38.845.87+38.8
- SimpleBenchGPT-5.5 by 28.96940.1+28.9
- CritPtGPT-5.5 by 26.827.10.3+26.8
- GPQA DiamondGPT-5.5 by 18.893.574.7+18.8
FactsGPT-5.5
- AA-Omniscience · AccuracyGPT-5.5 by 23.55834.5+23.5
- SimpleQA VerifiedGPT-5.5 by 21.96341.1+21.9
- AA-Omniscience · Non-hallucinationo1 by 19.41130.4+19.4
Images and chartsGPT-5.5
- LMArena · VisionGPT-5.5 by 124 rating points12921168+124 rating
- MathVistaGPT-5.5 by 12.484.271.8+12.4
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-5.5 by 35.274.939.7+35.2
- AA-OmniscienceGPT-5.5 by 31.520.5-11.1+31.5
- τ²-Bench Telecom (AA run)GPT-5.5 by 31.393.962.6+31.3
- FrontierMath (overall)GPT-5.5 by 29.935.45.5+29.9
- LiveBenchGPT-5.5 by 28.480.752.3+28.4
- AA IntelligenceGPT-5.5 by 23.238.415.2+23.2
- AA Agentic IndexGPT-5.5 by 6.237.331.1+6.2
Questions people ask
Which is better, GPT-5.5 or o1?
GPT-5.5 wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. o1 wins none.
Which is better for coding?
GPT-5.5. It wins 2 of the 2 coding tests both models report; o1 wins none.
Which is cheaper?
GPT-5.5 costs $5.00 per million input tokens and $30.00 per million output tokens; o1 costs $15.00 and $60.00. That makes GPT-5.5 about 53% cheaper for the same work.
How do you compare the two?
We use the 22 benchmark tests both models have published scores on. The verdict counts the 15 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.