GPT-5.5 vs Kimi K2.6
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.Kimi K2.6 is cheaper.
Scores updated · 55 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 own71GPT-5.57 of 8 tests
- MathCompetition and research-level math60GPT-5.56 of 6 tests
- CodingWriting and fixing software50GPT-5.55 of 7 tests · 2 ties
- ReasoningHard problems that need careful thinking40GPT-5.54 of 4 tests
- FactsGetting facts right instead of making them up31GPT-5.53 of 4 tests
- Images and chartsUnderstanding pictures, charts and video10GPT-5.51 of 2 tests · 1 tie
- Following instructionsDoing exactly what it is asked10GPT-5.51 of 2 tests · 1 tie
- Long documentsFinding answers in very long texts10GPT-5.51 of 1 test
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.
Kimi K2.6 costs 86% 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
- Proof problems from the US Math OlympiadUSAMO 2026+47points ahead
- Extremely hard research-level math problemsFrontierMath Tier 4+46.9points ahead
- Short factual questions, answered correctlySimpleQA Verified+28.1points ahead
Where Kimi K2.6 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+48.5points ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+1.9points ahead
Every test, side by side
All 55 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-5.5
- Terminal-Bench 2.1GPT-5.5 by 18.484.365.9+18.4
- Terminal-Bench HardGPT-5.5 by 16.760.643.9+16.7
- LiveBench · Agentic CodingGPT-5.5 by 7.15446.9+7.1
- SciCodeGPT-5.5 by 4.355.851.5+4.3
- LiveBench · CodingGPT-5.5 by 3.682.278.6+3.6
- LMArena · WebDevtie15131509tie
- SWE-bench Protie58.658.6tie
AgentsGPT-5.5
- GDPValGPT-5.5 by 15.742.727+15.7
- τ-Bench V3 · BankingGPT-5.5 by 15.73923.3+15.7
- AA IT-Bench SREGPT-5.5 by 14.645.831.2+14.6
- Terminal-Bench 4.0GPT-5.5 by 14.114.60.5+14.1
- AA ApexAgentsGPT-5.5 by 9.237.728.5+9.2
- MCP AtlasGPT-5.5 by 7.275.368.1+7.2
- OSWorld-VerifiedGPT-5.5 by 5.678.773.1+5.6
- BrowseCompKimi K2.6 by 1.984.486.3+1.9
ReasoningGPT-5.5
- CritPtGPT-5.5 by 19.127.18+19.1
- LiveBench · ReasoningGPT-5.5 by 10.389.779.4+10.3
- Humanity's Last ExamGPT-5.5 by 8.345.837.5+8.3
- GPQA DiamondGPT-5.5 by 2.493.591.1+2.4
FactsGPT-5.5
- AA-Omniscience · Non-hallucinationKimi K2.6 by 48.51159.5+48.5
- SimpleQA VerifiedGPT-5.5 by 28.16334.9+28.1
- AA-Omniscience · AccuracyGPT-5.5 by 25.45832.6+25.4
- Vectara HHEM hallucination ratelower is betterGPT-5.5 by 1.59.310.8+1.5
Images and chartsGPT-5.5
- LMArena · VisionGPT-5.5 by 10 rating points12921282+10 rating
- MMMU-Protie79.979.4tie
MathGPT-5.5
- USAMO 2026GPT-5.5 by 4798.251.2+47
- FrontierMath Tier 4GPT-5.5 by 46.972.525.6+46.9
- FrontierMath Tiers 1-3 (v2)GPT-5.5 by 28.185.357.2+28.1
- LiveBench · MathematicsGPT-5.5 by 11.695.984.3+11.6
- HMMT Feb. 2026GPT-5.5 by 5.898.592.7+5.8
- AIME 2026GPT-5.5 by 3.610096.4+3.6
Following instructionsGPT-5.5
- LiveBench · Instruction FollowingGPT-5.5 by 6.370.764.4+6.3
- IFBenchtie75.976tie
Other results21 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.
- GDPval-AA v2GPT-5.5 by 319 rating points15091190+319 rating
- GDPval-AA (Elo)GPT-5.5 by 287 rating points17691482+287 rating
- HiL-Bench (Tools-allowed)GPT-5.5 by 2139.718.7+21
- frontiermath_tier_4_v1GPT-5.5 by 20.835.414.6+20.8
- livebench_data_analysisGPT-5.5 by 16.581.665.1+16.5
- Terminal-Bench 2.0GPT-5.5 by 1682.766.7+16
- AA Agentic IndexGPT-5.5 by 15.237.322.1+15.2
- AA-OmniscienceGPT-5.5 by 15.220.55.3+15.2
- Artificial Analysis Coding IndexGPT-5.5 by 13.174.961.8+13.1
- BabyVisionKimi K2.6 by 12.655.968.5+12.6
- livebench_languageGPT-5.5 by 12.387.475.1+12.3
- AA IntelligenceGPT-5.5 by 11.438.427+11.4
- LiveBenchGPT-5.5 by 8.580.772.2+8.5
- Finance Agent v2GPT-5.5 by 6.951.844.9+6.9
- ToolathlonGPT-5.5 by 5.655.650+5.6
- τ²-Bench Telecom (AA run)Kimi K2.6 by 293.995.9+2
- HLE (with tools)Kimi K2.6 by 1.852.254+1.8
- vectara_factual_consistencyGPT-5.5 by 1.590.789.2+1.5
- vectara_avg_summary_lengthGPT-5.5 by 12.9 rating points129.6116.7+12.9 rating
- vectara_answer_ratetie10099.7tie
- Prophet Arenatie0.10.1tie
Questions people ask
Which is better, GPT-5.5 or Kimi K2.6?
GPT-5.5 wins all eight areas we test: coding, agents, reasoning, facts, images and charts, math, long documents and following instructions. Kimi K2.6 wins none, but costs 86% less.
Which is better for coding?
GPT-5.5. It wins 5 of the 7 coding tests both models report; Kimi K2.6 wins none, and 2 are ties.
Which is cheaper?
GPT-5.5 costs $5.00 per million input tokens and $30.00 per million output tokens; Kimi K2.6 costs $0.95 and $4.00. That makes Kimi K2.6 about 86% cheaper for the same work.
How do you compare the two?
We use the 55 benchmark tests both models have published scores on. The verdict counts the 34 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 21 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.