Compare · prices as of 18 Oct 2026
Claude Sonnet 5.5 vs DeepSeek V4.1 Flash
Price. Claude Sonnet 5.5 costs about 7–8× as much as DeepSeek V4.1 Flash at list price for our reference mix ($12–36 vs $96–272 per 100M tokens).
Coding rating. On LMArena's coding leaderboard their confidence intervals overlap (1513 vs 1501), so neither is clearly better there.
| USD per 1M tokens | Claude Sonnet 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| Input | $2.00 | $0.30 |
| Output | $10.00 | $1.20 |
| Cache read | $0.10 | $0.0060 |
| Cache write | $2.50 | = input |
| Per 100M tokens, reference mix (ours) | $96–272 | $12–36 |
| LMArena coding (95% CI) | 1513 (1498–1528, 1,627 votes) | 1501 (1491–1512, 3,527 votes) |
| Source | vendor page 2026-10-18 | vendor page 2026-10-18 |
Reference mix (ours): output is 5%–15% of tokens and cache reads are 30%–80% of the input side. We pick a high cache share because coding agents re-send their context on every step. Cache writes aren't counted. Put in your own numbers below. Coding ratings: LMArena coding leaderboard, published 2026-10-15, CC-BY-4.0. A rating is about head-to-head preference on coding prompts, not about your codebase.
Public coding benchmarks
| Benchmark | Claude Sonnet 5.5 | DeepSeek V4.1 Flash |
|---|---|---|
| LMArena codingas of 2026-10-15Data: LMArena (lmarena-ai/leaderboard-dataset), CC-BY-4.0, ratings rounded | 1513 (1498–1528)as “claude-sonnet-5.5-xhigh” | 1501 (1491–1512)as “deepseek-v4.1-flash-max” |
| SWE-bench Verified (bash-only)as of 2026-02-26 · older; may not cover this modelData: SWE-bench (swebench.com), CC BY-NC 4.0 | see leaderboard | see leaderboard |
| Aider polyglotas of 2025-11-20 · older; may not cover this modelData: Aider (Aider-AI/aider), Apache-2.0 | no public score | no public score |
Each row links its official leaderboard and the date of its latest update we saw (checked 18 Oct 2026). "no public score" means the model isn't on that leaderboard; we never borrow a score from an older or preview version. Aider polyglot has no public score for either model yet, so LMArena is the only current signal here.
Calculator
Runs in your browser. List prices as of 18 Oct 2026; cache writes not included. Results are ranges: ±3 points on output share and ±10 on cache share.
| Model | A month at list price |
|---|---|
| Claude Sonnet 5.5 | $66–111 (≈ ₹6,282–10,510) |
| DeepSeek V4.1 Flash | $8.58–14 (≈ ₹815–1,373) |
DeepSeek V4.1 Flash would cost about $58–96 less a month than Claude Sonnet 5.5 for this usage.
Not sure of your numbers? Drop your logs on the home page or run npx tokenreceipt for a range built from your own usage.
- DeepSeek V4.1 Flash: Peak-hour list rate (01:00-04:00 and 06:00-10:00 UTC, Mon-Fri). Off-peak is half: $0.15 / $0.60. We use peak to stay conservative.
Switching models mid-project costs more than the per-token price: a new model starts with a cold cache. Check your own logs to see whether the switch pays for you, or see all comparisons and the daily price index.