Compare · prices as of 18 Oct 2026
Claude Opus 5.5 vs GPT-6 Astra
Price. GPT-6 Astra costs about 3–3× as much as Claude Opus 5.5 at list price for our reference mix ($191–543 vs $516–1371 per 100M tokens).
Coding rating. On LMArena's coding leaderboard Claude Opus 5.5 is rated 56 points higher (1545 vs 1489), and the confidence intervals don't overlap.
| USD per 1M tokens | Claude Opus 5.5 | GPT-6 Astra |
|---|---|---|
| Input | $4.00 | $10.00 |
| Output | $20.00 | $50.00 |
| Cache read | $0.20 | $1.00 |
| Cache write | $5.00 | $12.50 |
| Per 100M tokens, reference mix (ours) | $191–543 | $516–1371 |
| LMArena coding (95% CI) | 1545 (1531–1559, 1,894 votes) | 1489 (1478–1501, 2,744 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 Opus 5.5 | GPT-6 Astra |
|---|---|---|
| LMArena codingas of 2026-10-15Data: LMArena (lmarena-ai/leaderboard-dataset), CC-BY-4.0, ratings rounded | 1545 (1531–1559)as “Claude Opus 5.5 (High)” | 1489 (1478–1501)as “gpt-6-astra-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 Opus 5.5 | $132–221 (≈ ₹12,564–21,019) |
| GPT-6 Astra | $347–564 (≈ ₹32,956–53,581) |
GPT-6 Astra would cost about $215–343 more a month than Claude Opus 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.
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.