Models, measured side by side
Claude Opus 5.5 vs DeepSeek V4.1 Flash
Compare Claude Opus 5.5, DeepSeek V4.1 Flash by token pricing, context length, benchmark results, speed and tool support.
Monthly workload
Monthly cost breakdown
InputOutput
Claude Opus 5.5
$180 / mo
DeepSeek V4.1 Flash
$7.00 / mo
Performance comparison
Claude Opus 5.5
57.6
DeepSeek V4.1 Flash
39.5
Overview
Pricing & capacity
| Pricing & capacity | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Input / 1M tokens | $4.00 | $0.05 |
| Output / 1M tokens | $20 | $1.20 |
| Cached input / 1M | $0.20 | $0.02 |
| Monthly cost | $180 | $7.00 |
| Context window | 1M | 1M |
| Maximum output | 128K | 944K |
Input / 1M tokens
- Claude Opus 5.5
- $4.00
- DeepSeek V4.1 Flash
- $0.05
Output / 1M tokens
- Claude Opus 5.5
- $20
- DeepSeek V4.1 Flash
- $1.20
Cached input / 1M
- Claude Opus 5.5
- $0.20
- DeepSeek V4.1 Flash
- $0.02
Monthly cost
- Claude Opus 5.5
- $180
- DeepSeek V4.1 Flash
- $7.00
Context window
- Claude Opus 5.5
- 1M
- DeepSeek V4.1 Flash
- 1M
Maximum output
- Claude Opus 5.5
- 128K
- DeepSeek V4.1 Flash
- 944K
Benchmarks & performance
| Benchmarks & performance | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Arena Elo | Not listed | Not listed |
| MMLU-Pro | Not listed | Not listed |
| Intelligence Index | 57.6 | 39.5 |
| GPQA | Not listed | Not listed |
| Humanity’s Last Exam | 61.4% | 39.2% |
| SciCode | 66.9% | 51.9% |
| Output speed | 91 tokens/s | 213 tokens/s |
| Time to first token | 755.54 s | 1.05 s |
| DesignArena rating | 1,407 | 1,325 |
| DesignArena win rate | 65.3% | 52.1% |
Arena Elo
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
MMLU-Pro
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Intelligence Index
- Claude Opus 5.5
- 57.6
- DeepSeek V4.1 Flash
- 39.5
GPQA
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Humanity’s Last Exam
- Claude Opus 5.5
- 61.4%
- DeepSeek V4.1 Flash
- 39.2%
SciCode
- Claude Opus 5.5
- 66.9%
- DeepSeek V4.1 Flash
- 51.9%
Output speed
- Claude Opus 5.5
- 91 tokens/s
- DeepSeek V4.1 Flash
- 213 tokens/s
Time to first token
- Claude Opus 5.5
- 755.54 s
- DeepSeek V4.1 Flash
- 1.05 s
DesignArena rating
- Claude Opus 5.5
- 1,407
- DeepSeek V4.1 Flash
- 1,325
DesignArena win rate
- Claude Opus 5.5
- 65.3%
- DeepSeek V4.1 Flash
- 52.1%
Tools & features
| Tools & features | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Function calling | Supported | Supported |
| Structured outputs | Supported | Supported |
| JSON mode | Supported | Supported |
| Reasoning | Supported | Supported |
| Built-in web search | Not listed | Not listed |
| Log probabilities | Not listed | Supported |
| Deterministic seed | Not listed | Supported |
| Parallel tool calls | Not listed | Not listed |
| Prompt caching | Supported | Supported |
Function calling
- Claude Opus 5.5
- Supported
- DeepSeek V4.1 Flash
- Supported
Structured outputs
- Claude Opus 5.5
- Supported
- DeepSeek V4.1 Flash
- Supported
JSON mode
- Claude Opus 5.5
- Supported
- DeepSeek V4.1 Flash
- Supported
Reasoning
- Claude Opus 5.5
- Supported
- DeepSeek V4.1 Flash
- Supported
Built-in web search
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Log probabilities
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Supported
Deterministic seed
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Supported
Parallel tool calls
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Prompt caching
- Claude Opus 5.5
- Supported
- DeepSeek V4.1 Flash
- Supported
API & availability
| API & availability | Claude Opus 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| API identifier | claude-opus-5.5 | deepseek-v4.1-flash |
| API providers | Not listed | Not listed |
| Knowledge cutoff | Not listed | Not listed |
| Prices checked | Oct 8, 2026 | Oct 8, 2026 |
API identifier
- Claude Opus 5.5
claude-opus-5.5- DeepSeek V4.1 Flash
deepseek-v4.1-flash
API providers
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Knowledge cutoff
- Claude Opus 5.5
- Not listed
- DeepSeek V4.1 Flash
- Not listed
Prices checked
- Claude Opus 5.5
- Oct 8, 2026
- DeepSeek V4.1 Flash
- Oct 8, 2026
About the models
Claude Opus 5.5
Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...
Full pricing & detailsDeepSeek V4.1 Flash
DeepSeek V4.1 Flash is a sparse mixture-of-experts model from DeepSeek, and the first built on the company's Causal Encoder-Decoder (CED) architecture. It activates 8B parameters on input and 16B on...
Full pricing & detailsComparison FAQ
Claude Opus 5.5: $4.00 input and $20 output per million tokens. DeepSeek V4.1 Flash: $0.05 input and $1.20 output per million tokens. The cheaper choice depends on your input-to-output ratio; a model can have a lower input rate but a higher output rate.