Claude Fable 5.1 wins on coding (100 vs 98). Claude Sonnet 5 wins on price ($3 vs $10/1M input). For most workflows, Claude Fable 5.1 is the stronger default — new frontier leader — better than fable 5 on every published benchmark, and cheaper to run.
The shortest way to see the safest default, the lower-cost option, and the specialist pick before you read deeper.
Claude Fable 5.1 is the safest overall answer here when you want the strongest default instead of the lowest list price.
Grok 4.5 is the lower-cost option to start with when you still need useful output at scale.
Claude Sonnet 5 is the better pick when response speed matters more than maximum reasoning depth.
Claude Fable 5.1 leads on coding with a score of 100 vs 98 for Claude Sonnet 5.
Claude Sonnet 5 is cheaper at $3/1M input tokens vs $10/1M for Claude Fable 5.1.
Claude Fable 5.1 is the stronger default for coding tasks.
Claude Fable 5.1 is the safer default: it is built for frontier agentic coding, long-horizon autonomous work, and agentic scientific research, which covers most of what people bring to this comparison.
Claude Sonnet 5 earns its place when your work is mostly high-volume agentic workloads and production apps at mid-tier pricing, even though it loses the overall count here.
Claude Sonnet 5 is the more cost-efficient option at $3/1M input — Claude Fable 5.1 costs 3x more per input token, so the gap is worth taking seriously wherever token volume rather than peak quality drives the bill.
Switch the scoring lens to see whether the top answer changes when you care more about cost, speed, or long-document work.
Anthropic / Premium / Sep 1, 2026
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Ranks models by the broadest mix of coding, writing, research, and long-context usefulness.
You need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding.
The fastest way to see where the recommendation shifts when your priority changes.
New frontier leader — better than Fable 5 on every published benchmark, and cheaper to run.
Best value Claude — agentic Sonnet speed with near-Opus capability.
Every figure below is the provider's list price or a published capability score — the same numbers the recommendation on this page is built from.
| Model | Input | Output | Est. month | Context | Speed | Coding | Writing | Research |
|---|---|---|---|---|---|---|---|---|
| Claude Fable 5.1Anthropic | $10.00/1M | $50.00/1M | $200 | 1M tokens | Deliberate | 100 | 98 | 100 |
| Claude Sonnet 5Anthropic | $3.00/1M | $15.00/1M | $60 | 1M tokens | Fast | 98 | 98 | 95 |
Capability scores are out of 100 and reflect our own weighting of published benchmarks and production signals — see how we evaluate models. “Est. month” assumes 10M input and 2M output tokens at list price, with no batch or caching discounts applied, so treat it as a ceiling.
What each one is genuinely good at, where it falls down, and the situations we would steer you away from it — not just the headline score.
Anthropic's September 1, 2026 frontier release and the new capability ceiling for coding, agents, and scientific work. Base pricing is unchanged at $10/$50, but cache reads dropped 75% to $0.25/1M — roughly 25% cheaper on typical workloads and up to 45% cheaper on agentic ones. 1M context, 128K output, adaptive thinking always on.
You need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding.
The new frontier leader, and the rare upgrade that costs less than the model it replaces. Base $10/$50 pricing did not move, but a 75% cut to cache reads makes typical workloads ~25% cheaper than Fable 5 and heavily agentic ones ~45% cheaper — while more than doubling Fable 5 on agentic science and beating Opus 5 on agentic coding. If you were already on Fable 5, switching is a straight win. If you were on Opus 5 for the price, it still costs 2x on uncached tokens.
Released September 1, 2026 alongside Claude Mythos 5.1, the first update to the Mythos-class line since Fable 5 on June 9. API ID claude-fable-5-1; generally available on the Claude API, Amazon Bedrock, Google Cloud, and Microsoft Foundry. Published launch numbers (Fable 5.1 / Fable 5 / Opus 5 / GPT-5.6 Sol): Terminal-Bench-Science 0.1 52.6 / 24.7 / 29.0 / 22.4; Terminal-Bench 4.0 55.8 / 42.0 / 52.3 / 37.3; CursorBench 3.2.0 73.4 / 70.5 / 70.0 / 67.2; AutomationBench 31.4 / 17.1 / 26.9 / 19.6; OSWorld 2.0 strict 41.7 / 36.1 / 39.6; Humanity's Last Exam (no tools) 60.9 / 57.8 / 56.6; GDPval-AA v2 1853 / 1723 / 1824 / 1711. GDPval-AA v2 is rescaled from the v1 numbers quoted on the Fable 5 page and is not directly comparable to them.
Anthropic's most agentic Sonnet yet — a fast 1M-context workhorse that narrows the gap to Opus-class quality at $3/$15, and the new default model on claude.ai.
You need the absolute top coding ceiling — Opus 5 leads SWE-bench Verified by over 20 points.
The best price-to-capability pick in the Claude lineup. Sonnet 5 replaces Sonnet 4.6 as the production default: markedly better agentic coding and computer use at the same standard price, with a $2/$10 promo through August 2026.
Released June 30, 2026. Default model for Free and Pro claude.ai plans. Promo pricing $2/$10 per 1M through Aug 31, 2026, then $3/$15. 128K max output, Jan 2026 knowledge cutoff.
UseRightAI recommendations are based on practical decision factors people actually feel in day-to-day use.
Newsletter
Useful if you care about ranking shifts, pricing changes, or a better recommendation appearing in this decision path.
No spam. Useful updates only. Affiliate disclosures always clearly labeled.
Claude Fable 5.1 wins on more of the categories we score — coding, research, long context — so it is the better default of the two. Claude Sonnet 5 is the better pick when your work is mostly high-volume agentic workloads and production apps at mid-tier pricing. Neither is universally "better": Claude Fable 5.1 is aimed at frontier agentic coding and long-horizon autonomous work, Claude Sonnet 5 at high-volume agentic workloads and production apps at mid-tier pricing.
Claude Sonnet 5 is cheaper at $3/1M input and $15/1M output. Claude Fable 5.1 costs $10/1M input and $50/1M output.
Both Claude Fable 5.1 and Claude Sonnet 5 have the same 1M context window.
Claude Fable 5.1 is better for coding with a score of 100 vs Claude Sonnet 5's 98 (out of 100). Claude Fable 5.1 is the overall coding leader in this directory at 100/100.
Claude Sonnet 5 is faster with a fast speed rating (score: 4) vs Claude Fable 5.1's deliberate rating (score: 2). Speed matters most for interactive and high-throughput work; for batch jobs the Claude Fable 5.1 latency penalty is usually invisible.
Base rates are still $10/$50 per 1M — double Claude Opus 5 for anything that is not cache-heavy. Anthropic published no SWE-bench Verified or SWE-bench Pro figure for 5.1 at launch. On Claude Pro it only runs on pay-as-you-go credits; Max includes it up to 50% of weekly limits. Avoid it if you need low latency, or your workload is uncached and cost-sensitive — Claude Opus 5 is half the base price and within a few points on agentic coding. That is the main case for looking at Claude Sonnet 5 instead.
Clearly behind Opus 5 and Fable 5 on the hardest reasoning and long-horizon agent tasks. Updated tokenizer produces ~1.0–1.35x more tokens for the same text, so effective cost runs above sticker price. Avoid it if you need the absolute top coding ceiling — Opus 5 leads SWE-bench Verified by over 20 points. Against Claude Fable 5.1 specifically, the gap shows up most on coding (100 vs 98).
Take a moderate workload of 10M input and 2M output tokens a month. Claude Fable 5.1 runs $200.00 (at $10/1M in and $50/1M out); Claude Sonnet 5 runs $60.00 (at $3/1M in and $15/1M out). That is a $140.00/month difference — Claude Sonnet 5 is the cheaper of the two at this volume, and the gap scales linearly as you send more. Output tokens dominate the bill on both, so prompt length matters far less than response length.
Yes, and for most teams that beats picking one. A common split is Claude Fable 5.1 for frontier agentic coding and long-horizon autonomous work, with Claude Sonnet 5 handling high-volume agentic workloads and production apps at mid-tier pricing. Routing high-volume, low-stakes calls to Claude Sonnet 5 at $3/1M and reserving Claude Fable 5.1 for the hard cases is usually the cheapest arrangement that does not cost you quality.