GPT-5.3-Codex vs Kimi K3.1 Pro Together
Full profiles: GPT-5.3-Codex (OpenAI) and Kimi K3.1 Pro Together (Moonshot AI): every benchmark, price and rank.
Updated · Data from 5 sources
As of 9 Nov 2026, GPT-5.3-Codex and Kimi K3.1 Pro Together are neck and neck on quality (62.9 vs 60.5 on the BenchLeader Index, inside the ±7.2 margin).
Key facts (as of 9 Nov 2026)
- GPT-5.3-Codex scores 62.9 on the BenchLeader Index and Kimi K3.1 Pro Together scores 60.5 (BenchLeader, 9 Nov 2026).
- GPT-5.3-Codex costs $4.81 per 1M tokens blended (list price, 9 Nov 2026).
GPT-5.3-Codex benchmarks xhigh OpenAI
Kimi K3.1 Pro Together benchmarks max Moonshot AIAdd a third modelWhich to pick for…
The pick's numbers come first. Category scores on the BenchLeader scale (50 is the average model, 15 points one standard deviation). High confidence means a lead of half a standard deviation or more; under one point is called either.
| Use case | Pick | Why | Confidence |
|---|---|---|---|
| High volume on a budget | Neither flagship | A smaller model is usually the better fit: Cheapest good LLMs, Fastest LLMs | – |
Key differences
- GPT-5.3-Codex (xhigh) and Kimi K3.1 Pro Together (max) are neck and neck on quality (62.9 vs 60.5, within the ±7.2 margin).
- GPT-5.3-Codex (xhigh) is stronger in agents & tools, coding, instruction following, long context, multimodal.
- Kimi K3.1 Pro Together (max) is stronger in knowledge, maths, reasoning.
At a glance
| Spec | GPT-5.3-Codex | Kimi K3.1 Pro Together |
|---|---|---|
| Developer | OpenAI | Moonshot AI |
| Released | 5 Feb 2026 | 23 Oct 2026 |
| Context window (tokens) | 400,000 | – |
| Compared at | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) |
| Open weights | No | No |
| Price in / out / cached input per 1M | $1.75 / $14.00 / $0.175 | – |
Category by category
Category scores on the BenchLeader scale: 50 is the average evaluated model, 15 points is one standard deviation. A gap under one point is called level.
| Category | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) | Leader |
|---|---|---|---|
| Reasoning | – | 67.1 | not comparable |
| Coding | 61.0 | – | not comparable |
| Agents & tools | 80.1 | – | not comparable |
| Maths | – | 65.8 | not comparable |
| Knowledge | – | 67.6 | not comparable |
| Instruction following | 73.6 | – | not comparable |
| Multimodal | 60.9 | – | not comparable |
| Long context | 66.4 | – | not comparable |
On one chart
Each domain on the index's own scale, where 50 is an average model. Click a domain to see the benchmarks behind it. Pick up to 5 models from the list.
Dashed: that model has no result on the axis it crosses; the line only joins its neighbours.
Not drawn, no result for these models: Human preference.
Where sources disagree
Across the 0 benchmarks both have, GPT-5.3-Codex leads 0, Kimi K3.1 Pro Together leads 0.
| Overall index | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) | Leader |
|---|---|---|---|
| BenchLeader Index | 62.9 | 60.5 | neck and neck |
Each publisher runs its own tasks, harnesses and effort settings, so their overall verdicts can differ; BenchLeader reconciles them on one scale. † measured at another effort setting of the same model (the publisher did not test the one compared here).
Price, speed and latency
List prices blended at three input tokens per output token. Per-task prices use the token counts on the methodology page. Cost, tokens and time per benchmark task are measured: Artificial Analysis’ averages over its whole Intelligence Index run.
| Measure | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|
| Blended price per 1M tokens | $4.81 | – |
| Input / output per 1M | $1.75 / $14.00 | – / – |
| Cached input per 1M | $0.175 | – |
| Price per task: chat reply | $0.0049 | – |
| Price per task: summarize a 30-page report | $0.029 | – |
| Price per task: code edit | $0.032 | – |
| Price per task: agentic coding session | $0.161 | – |
| Price per task: structured extraction | $0.0063 | – |
| Agentic coding session, input mostly cached | $0.090 | – |
| Output speed | 77 tok/s | – |
| Time to first answer | 42.9 s | – |
| Time to a complete answer | 85.0 s | – |
Each model is compared at its best-ranked reasoning-effort setting. GPT-5.3-Codex (xhigh) scores 62.9 and takes 43 s to its first answer token. Kimi K3.1 Pro Together (max) scores 60.5. Higher effort means more thinking before the answer: better scores, longer waits and more tokens billed. How reasoning effort changes scores and cost.
Every benchmark
33 benchmarks, grouped by category; each name links to the board and its leaders. † measured at another effort setting of the same model, shown for reference and not counted as a win.
| Metric | Publisher | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|---|
| BenchLeader Index | BenchLeader | 62.9 | 60.5 |
| Agents & tools score | BenchLeader | 80.1 | – |
| Coding score | BenchLeader | 61.0 | – |
| Instruction following score | BenchLeader | 73.6 | – |
| Long context score | BenchLeader | 66.4 | – |
| Multimodal score | BenchLeader | 60.9 | – |
| Knowledge score | BenchLeader | – | 67.6 |
| Maths score | BenchLeader | – | 65.8 |
| Reasoning score | BenchLeader | – | 67.1 |
| Blended price $/M | BenchLeader | $4.81 | – |
| Output speed | BenchLeader | 77 tok/s | – |
| Time to first answer | BenchLeader | 42.9 s | – |
| Context window | BenchLeader | 400,000 tokens | – |
| Reasoning | |||
| GPQA Diamond | Epoch AI Benchmarking Hub | – | 94.2% |
| GPQA Diamond (AA) | Artificial Analysis | 91.5% | – |
| Humanity's Last Exam (AA) | Artificial Analysis | 42.5% | – |
| CritPt | Artificial Analysis | 16.9% | – |
| Chess Puzzles | Epoch AI Benchmarking Hub | – | 45.0% |
| Mystery Game Puzzles | Epoch AI Benchmarking Hub | – | 42.0% |
| Coding | |||
| SWE-bench Verified (Epoch) | Epoch AI Benchmarking Hub | 74.8%† | – |
| WeirdML | WeirdML | 77.9% | – |
| Arena WebDev | Arena (LMArena) | 1406† | – |
| LiveCodeBench | Vals AI | 87.3% | – |
| IOI | Vals AI | 53.8% | – |
| SWE-bench (Vals) | Vals AI | 78.0% | – |
| Vibe Code Bench v1.1 | Vals AI | 61.8% | – |
| ALE-Bench | Epoch AI Benchmarking Hub | 1655.2 | – |
| Design Arena Website | Design Arena | 1159† | – |
| Agents & tools | |||
| Terminal-Bench | Terminal-Bench | 78.4%† | – |
| Terminal-Bench Hard | Artificial Analysis | 53.0% | – |
| τ²-Bench Telecom (AA) | Artificial Analysis | 86.0% | – |
| HiL-Bench | Scale AI SEAL | 4.3%† | – |
| Terminal-Bench 2.0 (Vals) | Vals AI | 64.0%† | – |
| METR Time Horizons | METR | 74.5%† | – |
| Vending-Bench 2 | Andon Labs | 5940.1† | – |
| AA-Briefcase v1.1 | Artificial Analysis | 868 | – |
| Design Arena Agentic | Design Arena | 1014† | – |
| Maths | |||
| FrontierMath Tiers 1–3 | Epoch AI Benchmarking Hub | – | 78.3% |
Show all 33 benchmarks
| Metric | Publisher | GPT-5.3-Codex (xhigh) | Kimi K3.1 Pro Together (max) |
|---|---|---|---|
| Maths | |||
| FrontierMath Tier 4 | Epoch AI Benchmarking Hub | – | 65.8% |
| OTIS Mock AIME | Epoch AI Benchmarking Hub | – | 100.0% |
| Knowledge | |||
| SimpleQA Verified | Epoch AI Benchmarking Hub | – | 62.2% |
| Instruction following | |||
| IFBench | Artificial Analysis | 75.4% | – |
| Multimodal | |||
| MMMU-Pro | Artificial Analysis | 78.5% | – |
| Long context | |||
| AA-LCR v1.1 | Artificial Analysis | 83.3% | – |
| Composite | |||
| AA Intelligence Index v4.3.2 | Artificial Analysis | 32.5 | – |
| AA Progress Index v1 | Artificial Analysis | 301.3 | – |
Data as of 2026-11-09. Best configuration of each model; every score links to its source on the model pages.
What changed
- Kimi K3.1 Pro Together (max): first results.
- GPT-5.3-Codex (xhigh): 1 new result (AA-Briefcase v1.1).
- GPT-5.3-Codex (xhigh): 1 new result (AA Progress Index v1).
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- Kimi K3.1 Pro Together vs GPT-6 Astra
- GPT-5.3-Codex vs Kimi K3
Rankings: Best LLM overall · Best LLM for agents · Best cheap LLMs
GPT-5.3-Codex vs Kimi K3.1 Pro Together: questions
- Is GPT-5.3-Codex better than Kimi K3.1 Pro Together?
- GPT-5.3-Codex (xhigh) and Kimi K3.1 Pro Together (max) are neck and neck on quality (62.9 vs 60.5, within the ±7.2 margin). The BenchLeader Index combines every independent quality benchmark; the two are within the margin of error as of 9 Nov 2026, so check the category scores for your use.
- When was Kimi K3.1 Pro Together released?
- Kimi K3.1 Pro Together was released on 23 Oct 2026.