Home / GPT-6 vs Claude Cost
Where does Claude Opus 5.5 land against the three GPT-6 tiers? On published rates it sits between Sol and Astra — 2× Sol on input and output. But cross-vendor math has a catch: caching works differently at Anthropic. Read the caveat before the numbers.
✓ Last verified: September 26, 2026 · Manually verifiedRead this before comparing across vendors. Anthropic's published "cached input" price ($0.20/1M) is the cache-hit rate — but cache writes cost 1.25–2× the base input price and are not modeled in our calculator. So Claude estimates below are a lower bound for workloads with heavy cache churn. Also note: the Flex/Batch 0.5× tier multipliers in the widget are OpenAI's published tiers, applied uniformly for comparison math — Anthropic runs its own discount programs with different terms, which we don't model. Full policy: methodology page.
Pick a model, set your workload, and watch all four update side by side. Prices come from the same data layer as every calculator on this site — never hard-coded per page.
Per 1M tokens, USD. GPT-6 rates are short-context Standard; Claude Opus 5.5 rates are Anthropic's published standard rates.
| Model | Input / 1M | Cached input / 1M | Output / 1M | Source |
|---|---|---|---|---|
| GPT-6 Luna | $0.10 | $0.01 | $0.50 | OpenAI |
| GPT-6 Sol | $2.00 | $0.20 | $10.00 | OpenAI |
| GPT-6 Astra | $10.00 | $1.00 | $50.00 | OpenAI |
| Claude Opus 5.5 | $4.00 | $0.20 * | $20.00 | Anthropic |
* Cache-hit rate. Cache writes (1.25–2× base input) are not modeled — see the caveat above.
Concrete workload — 30,000 input + 8,000 output tokens per request, 20,000 requests/month, 40% cached input, Standard tier:
| Per request | Per day | Per month | Per year | |
|---|---|---|---|---|
| GPT-6 Luna | $0.00592 | $3.95 | $118.40 | $1,420.80 |
| GPT-6 Sol | $0.11840 | $78.93 | $2,368.00 | $28,416.00 |
| GPT-6 Astra | $0.59200 | $394.67 | $11,840.00 | $142,080.00 |
| Claude Opus 5.5 | $0.23440 | $156.27 | $4,688.00 | $56,256.00 |
Opus 5.5 at $4,688/month sits squarely between Sol ($2,368) and Astra ($11,840): about 1.98× Sol and costs 39.6% as much as Astra (60.4% lower). In dollars: Opus 5.5 costs $2,320/month more than Sol and $7,152/month less than Astra on this workload. The per-request gap vs Sol is $0.1160 — small per call, $2,320/month at this volume. Remember the caveat: with cache churn, the real Anthropic bill lands somewhat above $4,688.
Here's where a plain rate table misleads: OpenAI discounts cached input to 0.1× base; Anthropic discounts cache hits to 0.05× base ($0.20 vs $4.00) — a deeper cut. On the example workload (40% cache), no-cache → cached: Opus 5.5 drops $5,600 → $4,688/month (−16.3%); Sol drops $2,800 → $2,368/month (−15.4%). So hit-heavy caching narrows the gap slightly in Claude's favor.
But the other half of Anthropic's cache story is missing from every calculator on this page: writing to cache costs 1.25–2× the base input rate ($5.00–$8.00/1M for Opus 5.5). If your cache turns over constantly — new documents every request, short-lived prefixes — those write charges eat the hit savings, and can erase them. Our numbers assume your cached tokens were written once and hit many times. If that doesn't describe your workload, treat the Claude column as optimistic.
Output-token share of the example bill: Luna 67.6%, Sol 67.6%, Astra 67.6%, Opus 5.5 68.3%. Output dominates everywhere — and it's the main reason Opus 5.5 lands where it does: its $20/1M output rate is 2× Sol's and the single biggest line item. Two practical reads: (1) if your workload is output-heavy, the cross-vendor ranking is decided almost entirely by output rates; (2) if it's input-heavy with high cache reuse, the vendors' different cache mechanics matter more than the headline input prices — and that's exactly where the write-cost caveat bites.
Math only, no verdicts. This page compares cost arithmetic, not model quality. It doesn't claim GPT-6 or Claude is "better" — and cross-vendor figures are directional estimates, not invoice predictions. Within OpenAI's three tiers the math is exact; across the vendor line, read the caveats.
Because caching mechanics differ by provider. Anthropic's cached-input figure is a cache-hit rate, while cache writes (1.25–2× the base input price) are not modeled in our calculator; token metering details also differ slightly. Treat cross-vendor numbers as directional estimates — within OpenAI the math is exact.
Cache hits and refreshes are billed at $0.20/1M (0.05× the base $4.00 input rate for Opus 5.5). Writing tokens into the cache costs 1.25–2× the base input rate. Our calculator models only the hit rate, so workloads with heavy cache churn will cost more than shown.
Pure math: Opus 5.5 rates are 2× Sol on input ($4.00 vs $2.00) and output ($20.00 vs $10.00), and equal on cached input ($0.20 each). On our example coding-agent workload Opus 5.5 costs $4,688/month versus Sol's $2,368/month — about 1.98×.
On cache hits, Anthropic's 0.05× discount is deeper than OpenAI's 0.1×, so hit-heavy workloads narrow the gap slightly — 16.3% saved versus 15.4% in our example. But the unmodeled cache-write surcharge (1.25–2× base) pushes the other way, so the net effect depends on your cache churn.
Both are verified on our methodology page — Sonnet 5 at $2.00/$0.20/$10.00 and Haiku 4.5 at $1.00/$0.10/$5.00 per 1M — but are not in this page's widget. Notably, Sonnet 5's rates exactly match GPT-6 Sol's, so the same Sol math applies to it.
The widget applies OpenAI's 0.5× Flex/Batch multipliers uniformly for comparison math. Anthropic runs its own batch and discount programs with different terms, which we do not model — compare at the Standard tier for the cleanest cross-vendor read.
Independence disclosure: this is an independent cost-estimation tool. It is not affiliated with, sponsored by, or endorsed by OpenAI, Anthropic, or Google. Prices are a snapshot last verified September 26, 2026 and may be outdated — always confirm on the provider's official pricing page before making decisions.