GPT-5.1 vs Kimi K2.5
Wins 5 of 7 areas
Coding · Reasoning · Facts · Long documents · Following instructions
Wins 1 of 7 areas
Images and charts
GPT-5.1 is the stronger all-rounder.Kimi K2.5 is cheaper and better at images and charts.
Scores updated · 41 tests both models report · How we compare
Where each one wins
Tests won in each of the seven areas where both have results. Each piece is one test, so a longer bar means more evidence; grey means the two scored within a point of each other.
- FactsGetting facts right instead of making them up40GPT-5.14 of 4 tests
- Following instructionsDoing exactly what it is asked20GPT-5.12 of 2 tests
- CodingWriting and fixing software32GPT-5.13 of 6 tests · 1 tie
- ReasoningHard problems that need careful thinking21GPT-5.12 of 4 tests · 1 tie
- Long documentsFinding answers in very long texts10GPT-5.11 of 1 test
- Images and chartsUnderstanding pictures, charts and video01Kimi K2.51 of 2 tests · 1 tie
- AgentsCarrying out multi-step tasks on its own11Even1 each · 1 tie
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 K2.5 costs 68% less for the same work.
The biggest differences
The three tests each model wins by the widest margin. Scores are out of 100.
Where GPT-5.1 pulls ahead
- Avoids making up answers it doesn't knowAA-Omniscience · Non-hallucination+13.8points ahead
- Short factual questions, answered correctlySimpleQA Verified+13.7points ahead
- Hard command-line tasks in a real terminalTerminal-Bench Hard+10.7points ahead
Where Kimi K2.5 pulls ahead
- Finds hard-to-locate facts by browsing the webBrowseComp+24.1points ahead
- Code for real scientific research problemsSciCode+5.7points ahead
- Very hard expert questions across many subjectsHumanity's Last Exam+2.2points ahead
Every test, side by side
All 41 tests both models report. The winning score is in its model's colour; marks a score checked independently.
CodingGPT-5.1
- Terminal-Bench HardGPT-5.1 by 10.745.534.8+10.7
- Terminal-Bench 2.1GPT-5.1 by 6.752.445.7+6.7
- SciCodeKimi K2.5 by 5.743.349+5.7
- LMArena · WebDevKimi K2.5 by 41 rating points13951436+41 rating
- LiveCodeBench v6GPT-5.1 by 28785+2
- SWE-bench Verifiedtie76.376.8tie
AgentsEven
- BrowseCompKimi K2.5 by 24.150.874.9+24.1
- τ-Bench V3 · BankingGPT-5.1 by 1.715.914.2+1.7
- GDPValtie16.517.2tie
ReasoningGPT-5.1
- ARC-AGI-2GPT-5.1 by 5.817.611.8+5.8
- Humanity's Last ExamKimi K2.5 by 2.228.530.7+2.2
- CritPtGPT-5.1 by 1.84.93.1+1.8
- GPQA Diamondtie87.387.9tie
FactsGPT-5.1
- AA-Omniscience · Non-hallucinationGPT-5.1 by 13.848.134.3+13.8
- SimpleQA VerifiedGPT-5.1 by 13.74834.3+13.7
- AA-Omniscience · AccuracyGPT-5.1 by 2.537.735.2+2.5
- Vectara HHEM hallucination ratelower is betterGPT-5.1 by 2.112.114.2+2.1
Images and chartsKimi K2.5
- LMArena · VisionKimi K2.5 by 19 rating points12501269+19 rating
- MMMU-Protie75.575.4tie
Following instructionsGPT-5.1
- IFBenchGPT-5.1 by 2.772.970.2+2.7
- Multi-ChallengeGPT-5.1 by 263.461.4+2
Other results19 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.
- vectara_avg_summary_lengthGPT-5.1 by 142.4 rating points254.4112+142.4 rating
- τ²-Bench Telecom (AA run)Kimi K2.5 by 1481.995.9+14
- AA-OmniscienceGPT-5.1 by 12.75.4-7.3+12.7
- frontiermath_tier_4_v1GPT-5.1 by 8.312.54.2+8.3
- vectara_answer_rateGPT-5.1 by 7.810092.2+7.8
- ARC-AGI-1GPT-5.1 by 7.572.865.3+7.5
- HLE (with tools)Kimi K2.5 by 7.542.750.2+7.5
- swe_bench_bashKimi K2.5 by 4.86670.8+4.8
- matharena_visual_math_overallKimi K2.5 by 3.776.980.6+3.7
- Terminal-Bench 2.0Kimi K2.5 by 3.247.650.8+3.2
- τ²-BenchKimi K2.5 by 2.782.785.4+2.7
- Artificial Analysis Coding IndexGPT-5.1 by 2.649.446.8+2.6
- HMMT Nov. 2025GPT-5.1 by 2.591.789.2+2.5
- AIME 2025Kimi K2.5 by 2.19496.1+2.1
- vectara_factual_consistencyGPT-5.1 by 2.187.985.8+2.1
- AA IntelligenceGPT-5.1 by 1.224.723.5+1.2
- HMMT Feb. 2025tie96.395.4tie
- AA Agentic Indextie21.621.7tie
- MMLU-Protie8787.1tie
Questions people ask
Which is better, GPT-5.1 or Kimi K2.5?
GPT-5.1 wins five of the seven areas where both have results: coding, reasoning, facts, long documents and following instructions. Kimi K2.5 wins images and charts, and costs 68% less. They are level on agents.
Which is better for coding?
GPT-5.1. It wins 3 of the 6 coding tests both models report; Kimi K2.5 wins 2, and 1 is a tie.
Which is cheaper?
GPT-5.1 costs $1.25 per million input tokens and $10.00 per million output tokens; Kimi K2.5 costs $0.60 and $3.00. That makes Kimi K2.5 about 68% cheaper for the same work.
How do you compare the two?
We use the 41 benchmark tests both models have published scores on. The verdict counts the 22 tests in the eight capability areas, and a gap under one point (ten on rating-style scales) counts as a tie. The other 19 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.