Claude Sonnet 5.5 API pricing
Official Anthropic list price, last checked Oct 29, 2026. Updated Oct 29, 2026.
Claude Sonnet 5.5 costs $2 per 1M input tokens and $10 per 1M output tokens, cached input at $0.10, and a 1M-token context window, per Anthropic's official pricing page (checked Oct 29, 2026). It's a premium-priced model: number 63 of 77 by blended price ($4 per 1M tokens at a 3 to 1 input to output mix). On LMArena's Code Arena it ranks #3 of 50 models we price (relative score 85 out of 100). Nothing cheaper scores close to it on that board; GPT-6.1 Terra is the nearest cheaper option.
Claude Sonnet 5.5 price per million tokens
| Claude Sonnet 5.5 price per million tokens | USD |
|---|---|
| Input | $2 |
| Cached input | $0.10 |
| Output | $10 |
| Blended, 3 parts input to 1 part output | $4 |
| Context window | 1M tokens |
Official note from Anthropic: 5-minute cache writes $2.50.
What Claude Sonnet 5.5 costs for real work
List-price estimates for a month, no discounts. Our math, not a quote: change the token counts in the plan vs API calculator.
| Workload | Tokens a month | Claude Sonnet 5.5 | GPT-6.1 Sol | GPT-6.1 Terra |
|---|---|---|---|---|
| Light: a side project or personal assistant | 2M in, 0.5M out | $9.00 | $9.00 | $4.50 |
| Medium: a small team or one product feature | 20M in, 5M out | $90.00 | $90.00 | $45.00 |
| Heavy: a production app | 200M in, 50M out | $900 | $900 | $450 |
| Medium with 80% of input cached | 20M in (16M cached), 5M out | $59.60 | $59.60 | $29.80 |
How Claude Sonnet 5.5 ranks on LMArena
Relative score: 100 is the top model we price on that board. Rank is among the models in our price table, not the full leaderboard.
| Board | Rank | Score /100 |
|---|---|---|
| Coding (Code Arena) | #3 of 50 | 85 |
| Chat (Text Arena) | #16 of 51 | 18 |
| Creative writing (Text Arena creative writing) | #10 of 51 | 31 |
| Roleplay and characters (Text Arena multi-turn) | #17 of 51 | 1 |
| Reasoning and math (Text Arena math) | #8 of 51 | 57 |
| Vision (Vision Arena) | #16 of 33 | 22 |
| Cheap bulk and agents (Agent Arena) | #2 of 34 | 81 |
Closest rivals to Claude Sonnet 5.5
The models nearest in price, other makers first. Ranks are on Code Arena, where we have them.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| GPT-6.1 Sol | $2 / $10 | $4 | Claude Sonnet 5.5 wins: same price, higher score. Compare |
| GPT-6 Sol | $2 / $10 | $4 | Claude Sonnet 5.5 wins: same price, higher score. Compare |
| Gemini 4 Argon | $2 / $10 | $4 | Claude Sonnet 5.5 wins: same price, higher score. Compare |
| Kimi K3.1 Pro | $2 / $10 | $4 | Claude Sonnet 5.5 wins: same price, higher score. Compare |
Cheaper alternatives to Claude Sonnet 5.5
At least 40% cheaper blended, best LMArena score first.
| Model | In / out | Blended | Verdict |
|---|---|---|---|
| GPT-6.1 Terra | $1 / $5 | $2 | GPT-6.1 Terra for price, Claude Sonnet 5.5 for quality. Compare |
| DeepSeek V4.1 Flash | $0.30 / $1.20 | $0.525 | DeepSeek V4.1 Flash for price, Claude Sonnet 5.5 for quality. Compare |
| Muse Spark 1.3 | $1.25 / $4.25 | $2 | Muse Spark 1.3 for price, Claude Sonnet 5.5 for quality. Compare |
More from Anthropic
- Claude Haiku 5.5$0.10 in, $0.50 out per 1M
- Claude Opus 5.5$4 in, $20 out per 1M
- Claude Opus 5$5 in, $25 out per 1M
- Claude Fable 5.1$10 in, $50 out per 1M
FAQ
How much does the Claude Sonnet 5.5 API cost per million tokens?
$2 per 1M input tokens and $10 per 1M output tokens, plus $0.10 per 1M for cached input, as of Oct 29, 2026. A typical 3 to 1 input to output mix works out to $4 per 1M tokens.
Does Claude Sonnet 5.5 charge more for long prompts?
Anthropic doesn't list a long-prompt surcharge for Claude Sonnet 5.5. Its pricing note says: 5-minute cache writes $2.50.
Is Claude Sonnet 5.5 cheaper than GPT-6.1 Sol?
About the same. A medium month (20M input and 5M output tokens) costs $90.00 on Claude Sonnet 5.5 and $90.00 on GPT-6.1 Sol at list price. On Code Arena, Claude Sonnet 5.5 ranks #3 and GPT-6.1 Sol #4.
How does Claude Sonnet 5.5 rank on LMArena?
On Code Arena it is #3 of 50 models we price, with a relative score of 85 out of 100. It ranks on 7 of 8 boards we track.
What is a cheaper alternative to Claude Sonnet 5.5?
GPT-6.1 Terra costs $1 in and $5 out per 1M tokens, about 2.0x less blended, and scores 49 on Code Arena against 85 for Claude Sonnet 5.5.
Where does this Claude Sonnet 5.5 price come from?
From Anthropic's official pricing page, which we check every day. This page was last checked Oct 29, 2026.