text model comparison
Claude Sonnet 5.5 vs Kimi K3.1 Pro
Claude Sonnet 5.5 and Kimi K3.1 Pro are both current text models, from Anthropic and Moonshot Kimi. Both cost $2 per 1M input tokens. Both accept about 1.05M tokens of context (1,048,576 and 1,000,000).
- Longer context window
- Kimi K3.1 Pro1.05M tokens against 1M tokens
- Newer release
- Kimi K3.1 ProOct 2026 against Sep 2026
Data verified October 28, 2026 · Dataset 2026-10-28
Side by side
Claude Sonnet 5.5 and Kimi K3.1 Pro, line by line
Prices in effect today, compared at the same tier wherever both list one. The better value in each row is highlighted.
| Fact | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Price | ||
| Price per 1M input tokens | $2 | $2 |
| Price per 1M output tokens | $10 | $10 |
| Independent benchmarks | ||
| Arena Text | 1476 Elo (#20 of 49) | Not measured |
| GPQA Diamond | 95.6% (#2 of 40) | Not measured |
| FrontierMath Tiers 1-3 (v2) | 88.8% (#7 of 40) | Not measured |
| SimpleQA Verified | 46.5% (#22 of 36) | Not measured |
| Specs | ||
| Provider | Anthropic | Moonshot Kimi |
| Release date | September 28, 2026 | October 23, 2026 |
| Access | API only | API only |
| Context window | 1,000,000 tokens | 1,048,576 tokens |
| Max output | 128,000 tokens | Not reported |
| Input | text, image | text, image, video |
| Output | text | text |
No independent benchmark has scored both models yet. Each rank counts the current models scored on that benchmark.
Charts
Against every current text model
Where Claude Sonnet 5.5 and Kimi K3.1 Pro land among the current models of their task, on every independent benchmark, on price and on context.
Where each stands
Only Claude Sonnet 5.5 has a current Arena Text score: #20 of 49. Each bar is the share of current models it beats.
Independent benchmarks
Arena Text
Claude Sonnet 5.5:#20of 49
1,476 Elo · ahead of 60%
Kimi K3.1 Pro: Not scored
GPQA Diamond
Claude Sonnet 5.5:#2of 40
95.6% · ahead of 97%
Kimi K3.1 Pro: Not scored
FrontierMath Tiers 1-3 (v2)
Claude Sonnet 5.5:#7of 40
88.8% · ahead of 85%
Kimi K3.1 Pro: Not scored
SimpleQA Verified
Claude Sonnet 5.5:#22of 36
46.5% · ahead of 40%
Kimi K3.1 Pro: Not scored
Price and context
Price per 1M input tokens
Claude Sonnet 5.5:#28of 51
$2 · cheaper than 24%
Kimi K3.1 Pro:#28of 51
$2 · cheaper than 24%
Price per 1M output tokens
Claude Sonnet 5.5:#33of 51
$10 · cheaper than 26%
Kimi K3.1 Pro:#33of 51
$10 · cheaper than 26%
Context window
Claude Sonnet 5.5:#28of 66
1M tokens · longer than 22%
Kimi K3.1 Pro:#11of 66
1.05M tokens · longer than 65%
Quality against price
Claude Sonnet 5.5 scores 1,476 at $4 (blended price per 1M tokens). The line joins the current models no other beats on both price and Arena Text score; hover any point to name it.
Quality against price: the data
| Model | Provider | Blended price per 1M tokens | Arena Text (Elo) |
|---|---|---|---|
| Gemini 4 Argon | $4 | 1,525 | |
| Claude Opus 5.5 | Anthropic | $8 | 1,507 |
| Claude Fable 5 | Anthropic | $20 | 1,504 |
| Claude Fable 5.1 | Anthropic | $20 | 1,501 |
| Gemini 3.8 Flash | $1.50 | 1,497 | |
| Muse Spark 1.3 | Meta | $2 | 1,494 |
| Claude Opus 5 | Anthropic | $10 | 1,490 |
| Kimi K3 | Moonshot Kimi | $6 | 1,488 |
| Gemini 3.7 Flash | $1.50 | 1,486 | |
| GPT-5.6 Sol | OpenAI | $8 | 1,485 |
| GPT-6.1 Sol | OpenAI | $4 | 1,484 |
| Qwen3.8-Max | Alibaba Qwen | $3 | 1,483 |
| GPT-5.5 | OpenAI | $11 | 1,482 |
| Gemini 3.6 Flash | $3 | 1,482 | |
| Claude Opus 4.8 | Anthropic | $10 | 1,481 |
| MiMo-V2.6-Pro | Xiaomi MiMo | $0.54 | 1,480 |
| GLM-5.3 | Z.ai | $2.15 | 1,478 |
| Claude Sonnet 5.5 | Anthropic | $4 | 1,476 |
| GPT-5.4 | OpenAI | $5.63 | 1,475 |
| GPT-6 Astra | OpenAI | $20 | 1,475 |
| DeepSeek-V4.1-Flash | DeepSeek | $0.52 | 1,475 |
| GLM-5.3-Flash | Z.ai | $0.24 | 1,475 |
| Gemini 3 Flash Preview | $1.13 | 1,473 | |
| Grok 4.20 | xAI | $1.56 | 1,472 |
| GPT-5.6 Terra | OpenAI | $4.50 | 1,466 |
| Grok 4.5 | xAI | $3 | 1,466 |
| DeepSeek-V4-Pro | DeepSeek | $1.98 | 1,465 |
| Claude Sonnet 5 | Anthropic | $4 | 1,461 |
| GPT-6 Sol | OpenAI | $4 | 1,456 |
| Gemini 3.5 Flash-Lite | $0.85 | 1,455 | |
| Grok 4.6 | xAI | $3 | 1,454 |
| GPT-5.6 Luna | OpenAI | $0.45 | 1,452 |
| MiMo-V2.6-Flash | Xiaomi MiMo | $0.18 | 1,451 |
| GPT-6 Luna | OpenAI | $0.20 | 1,443 |
| Grok 4.7 | xAI | $3 | 1,443 |
| Grok 4.3 | xAI | $1.56 | 1,442 |
| Mistral Large 4 | Mistral AI | $2.06 | 1,429 |
| GPT-4.1 | OpenAI | $3.50 | 1,415 |
| Solar Pro 4 | Upstage | $0.52 | 1,386 |
| GPT-4.1 mini | OpenAI | $0.70 | 1,383 |
| GPT-4.1 nano | OpenAI | $0.18 | 1,322 |
Cost
What each costs
Example workloads at each provider's listed rates, then every other rate either one lists. The cheaper figure in each row is highlighted.
The same work, priced
At each provider's listed rates.
10M input and 2M output tokens
The same price
- Claude Sonnet 5.5
- $40
- Kimi K3.1 Pro
- $40
The same, with 9M of the input tokens cached
Kimi K3.1 Pro costs 1.0× as much
- Claude Sonnet 5.5
- $22.90
- Kimi K3.1 Pro
- $23.80
| Workload or rate | Claude Sonnet 5.5 | Kimi K3.1 Pro |
|---|---|---|
| Example workloads | ||
| 10M input and 2M output tokens | $40 | $40 |
| The same, with 9M of the input tokens cached | $22.90 (better) | $23.80 |
| The same, through the batch API | $20 | Not listed |
| Other listed rates | ||
| 1M input tokens, cached | $0.10 (better) | $0.20 |
| 1M input tokens, 5-minute cache write | $2.50 | $2 (better) |
| 1M input tokens, 1-hour cache write | $4 | $4 |
| 1M input tokens, batch | $1 | Not listed |
| 1M output tokens, batch | $5 | Not listed |
| 1M input tokens, Highspeed endpoint | Not listed | $4 |
| 1M output tokens, Highspeed endpoint | Not listed | $20 |
Verdict
When to choose each
Claude Sonnet 5.5
Where it leads
- Cheaper cached input, $0.10 vs $0.20 per 1M tokens
- Batch pricing, $1 input and $5 output per 1M tokens
Best for
- Production workloads that need frontier-adjacent quality at a mid-tier rate
- Latency-sensitive agent steps inside a larger pipeline
Watch out for
- Same list price as Claude Sonnet 5, so the gain is capability and cache economics rather than a cheaper rate card
- Anthropic positions Opus 5.5 rather than this as the default, so reach for Sonnet 5.5 when latency matters more than peak capability
Kimi K3.1 Pro
Where it leads
- Accepts video input
Best for
- Long-horizon coding and agent work at mid-tier prices
- Long documents, images and video in one 1M-token context
Watch out for
- Thinking is always on: reasoning effort runs low, high or max, and max is the default
- The Highspeed endpoint, two to three times faster by Moonshot's account, costs twice as much at $4 input and $20 output per 1M tokens
- Weights are promised by 4 November 2026 and were not out when this record was made; no independent benchmark score is recorded here yet
From benchmark to production
Building on Claude Sonnet 5.5 or Kimi K3.1 Pro?
Public scores rarely hold on your own data. We test both models on your real tasks, then build the agent or pipeline around the one that wins.
FAQ
Claude Sonnet 5.5 vs Kimi K3.1 Pro FAQ
Which is cheaper, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Both cost $2 per 1M input tokens. For 10M input and 2M output tokens, Claude Sonnet 5.5 costs $40 and Kimi K3.1 Pro $40 at standard rates.
Which is cheaper with prompt caching, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Claude Sonnet 5.5 charges $0.10 per 1M cached input tokens, 95% below its standard input rate, and Kimi K3.1 Pro $0.20, 90% below. With 9M of 10M input tokens cached and 2M output tokens, Claude Sonnet 5.5 costs $22.90 and Kimi K3.1 Pro $23.80.
Which has the larger context window, Claude Sonnet 5.5 or Kimi K3.1 Pro?
Both accept about 1.05M tokens of context (1,048,576 and 1,000,000).
How do Claude Sonnet 5.5 and Kimi K3.1 Pro differ in features?
Claude Sonnet 5.5 takes text and image input; Kimi K3.1 Pro takes text, image and video.
Further reading
More on Claude Sonnet 5.5 and Kimi K3.1 Pro
Articles on Claude Sonnet 5.5 and Kimi K3.1 Pro
- Kimi K3.1 Pro: Benchmarks, Price and Should You Switch?October 25, 2026
- Claude Sonnet 5.5 vs GPT-6 Luna: Cost, Speed and AccuracySeptember 29, 2026
- Claude Sonnet 5.5: Benchmarks, Price and When to Use OpusSeptember 29, 2026
Related comparisons
- Claude Sonnet 5.5 vs GPT-6.1 Sol
- Claude Sonnet 5 vs Kimi K3.1 Pro
- Claude Sonnet 5.5 vs Gemini 3.8 Flash
- Gemini 4 Argon vs Kimi K3.1 Pro
- Claude Sonnet 5.5 vs GPT-4.1
- GPT-4.1 vs Kimi K3.1 Pro
- Claude Sonnet 5.5 vs GPT-5.4
- Kimi K3 vs Kimi K3.1 Pro
- Claude Sonnet 5.5 vs GPT-5.6 Terra
- Claude Sonnet 5.5 vs GPT-6 Luna
- Claude Sonnet 5.5 vs GPT-6 Sol
- Claude Sonnet 5.5 vs Grok 4.5
Production evaluation
Choosing between Claude Sonnet 5.5 and Kimi K3.1 Pro?
Public benchmarks narrow the shortlist. We run both on your own tasks, data and cost limits, then build the routing and review controls to run the winner in production.
- A head-to-head evaluation on your real workload
- Routing between models by cost and difficulty