Cost and performance comparison
Claude Fable 5 vs Claude 3 Opus
Model AAnthropic
Claude Fable 5
- Cost / 1M Tokens
- $22.00
- 70% in · 30% out mix
- ≈ $31.46 for the same text, tokenizer included
- Value Index (score÷cost)
- 3.2
- Higher = better value
- Speed
- 55/100
- Context
- 1.0M
- Tier
- Power Tier
List price from the Anthropic pricing page, verified October 12, 2026.
Its tokenizer produces about 43% more tokens than OpenAI's for the same text, so the real cost runs higher than the list price suggests. This is an estimate: the tokenizer has not been measured yet.
Check the sourceModel BAnthropic
Claude 3 Opus
- Cost / 1M Tokens
- $33.00
- 70% in · 30% out mix
- ≈ $36.30 for the same text, tokenizer included
- Value Index (score÷cost)
- 2.5
- Higher = better value
- Speed
- 50/100
- Context
- 200K
- Tier
- Power Tier
Last list price before the model was retired.
Its tokenizer produces about 10% more tokens than OpenAI's for the same text, so the real cost runs higher than the list price suggests. This is an estimate: the tokenizer has not been measured yet.
In-depth analysis
Claude Fable 5 vs Claude 3 Opus: Detailed Comparison
Claude Fable 5 is Anthropic's flagship-tier language model with a 1.0M-token context window, excelling at coding. Claude 3 Opus from Anthropic is a flagship-tier model supporting 200K tokens in context, with standout performance in reasoning.
Price is not the deciding factor here. For the same text, Claude Fable 5 and Claude 3 Opus land within 13% of each other, which is inside the margin your own input/output ratio will move anyway. Pick on capability, context, or latency instead — the monthly bill will look much the same either way. Claude Fable 5 is priced at $10.00/M input tokens and $50.00/M output tokens. Claude 3 Opus costs $15.00/M input and $75.00/M output.
Claude Fable 5 turns the same text into about 30% more tokens than Claude 3 Opus, because their tokenizers differ — so comparing list prices per token understates what Claude Fable 5 costs. For the same text, split 70% input and 30% output and counted the way OpenAI's tokenizer counts it, Claude Fable 5 works out at about $31.46 per million tokens and Claude 3 Opus at $36.30. Every cost figure on this page includes that difference.
On iOPTERA's editorial scores, Claude Fable 5 leads with 100/100 for coding and 100/100 for reasoning, against Claude 3 Opus's 80/100 and 90/100.
Capability breakdown
Across the five core benchmark categories, here is how Claude Fable 5 and Claude 3 Opus stack up head to head:
Best model by task
- coding: Claude Fable 5 wins with 100/100
- reasoning: Claude Fable 5 wins with 100/100
- data extraction: Claude Fable 5 wins with 97/100
- creative tasks: Claude Fable 5 wins with 98/100
- vision/multimodal: Claude Fable 5 wins with 96/100
Estimated monthly cost at scale
For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), Claude Fable 5 runs about $286.00 while Claude 3 Opus runs about $330.00 — Claude Fable 5 saves roughly $44.00 (13%) every month.
What actually decides it
Both models come from Anthropic, so they share a tokenizer, an API surface, and a billing account. Switching between them is a model-string change and nothing else — no new SDK, no re-tokenizing your prompts to re-estimate cost, no second vendor to onboard. That makes routing between them far cheaper to implement than a cross-vendor split.
These are the same lab's model at the same tier, 27 months apart — so this is an upgrade question, not a choice between alternatives. Claude Fable 5 is the current entry; Claude 3 Opus is here because plenty of production traffic still runs on it. If you are starting something new there is little reason to pick the older one, and if you are already on it the question is whether the migration cost is worth the gain.
The context gap is the largest single difference on this pair: Claude Fable 5 takes 1.0M tokens against 200K for Claude 3 Opus, roughly 5.0x. That is the difference between feeding in a whole repository or a full contract set and having to chunk it. If your work involves documents you cannot split cleanly, this decides it on its own.
Throughput is close enough to ignore — 55/100 versus 50/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.
One practical asymmetry: Claude Fable 5 offers a batch API at 50% off standard rates, and Claude 3 Opus does not. For anything that does not need an answer immediately — nightly enrichment, backfills, evaluation runs — that discount can be worth more than the difference in list price, and it is easy to overlook when comparing headline rates.
With prices this close (13% apart), pick on fit rather than cost. Claude Fable 5 holds the benchmark edge; weigh that against where each one is weakest — vision processing and coding respectively — and use the calculator above with your own token mix.
What you actually pay
The list price is only the start. Prompt caching, batch processing and long prompts change the bill, and each provider sets them differently. Prices per 1M tokens.
| Pricing term | Claude Fable 5 | Claude 3 Opus |
|---|---|---|
| List price (input / output) | $10.00 / $50.00 | $15.00 / $75.00 |
| Cached input | $1.0010% of the input price | — |
| Batch API | 50% off input and output | — |
| Long prompts | No surcharge across the 1M window | — |
| Input with 80% cache hits | $2.80 | — |
The last row assumes 80% of input tokens are read from the cache, as in a chat app that re-sends a long system prompt or RAG over the same documents. Cache-write and storage charges are not included.
Claude also bills cache writes: 1.25× the input price for a 5-minute cache, 2× for one hour.
Checked on October 8, 2026 against the pricing pages of Anthropic.
Capability scores
iOPTERA editorial scores across 5 categories — informed by public benchmarks, not measured by us
Coding
Reasoning
Extraction
Creative
Vision
Speed Score
Context Window
What Is a Token?
Models don't read words — they process tokens.
A token is roughly 4 characters of English text (~¾ of a word). Your API bill is priced per million tokens — understanding this directly reduces your costs.
Short phrase
"Hello, world!"
- Claude Fable 5
- $5.72
- Claude 3 Opus
- $6.60
Business email
One typical email (~200 words)
- Claude Fable 5
- $386.10
- Claude 3 Opus
- $445.50
Code file
50-line Python script
- Claude Fable 5
- $572.00
- Claude 3 Opus
- $660.00
Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both Claude Fable 5 and Claude 3 Opus, so the number only becomes meaningful at production volume. Input tokens only; add your output volume in the calculator below.
How to check your token usage
response.usage.total_tokensEvery API response includes a usage object. Sum total_tokens across all calls to get your monthly figure, then use the calculator below.
Your Cost Calculator
Enter your actual monthly token usage to see real savings
Quick Presets
Claude Fable 5
$943.80/mo
$11,325.60/yr
Claude 3 Opus
$1,089.00/mo
$13,068.00/yr
Annual Savings
$1,742.40 saved per year
Claude Fable 5 cheaper · $145.20/mo
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