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Cost and performance comparison

Claude Fable 5 vs Claude Sonnet 5

Model AAnthropic

Claude Fable 5

Capability score (editorial)100/100
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 source

How we verify prices

Model BAnthropic

Claude Sonnet 5

Capability score (editorial)92/100
Cost / 1M Tokens
$4.40
70% in · 30% out mix
≈ $6.29 for the same text, tokenizer included
Value Index (score÷cost)
14.6
Higher = better value
Speed
88/100
Context
1.0M
Tier
Smart 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 source

How we verify prices

In-depth analysis

Claude Fable 5 vs Claude Sonnet 5: Detailed Comparison

Claude Fable 5 is Anthropic's flagship-tier language model with a 1.0M-token context window, excelling at coding. Claude Sonnet 5 from Anthropic is a mid-range-tier model supporting 1.0M tokens in context, with standout performance in coding.

Claude Fable 5 costs 5.0x what Claude Sonnet 5 does for the same text. That is a steep premium, and it buys a 13-point lead on combined coding and reasoning. Whether that trade is worth it depends entirely on how much of your traffic actually needs the harder model — for most workloads the honest answer is a small fraction of it, which is an argument for routing rather than for picking one. Claude Fable 5 is priced at $10.00/M input tokens and $50.00/M output tokens. Claude Sonnet 5 costs $2.00/M input and $10.00/M output.

On iOPTERA's editorial scores, Claude Fable 5 leads with 100/100 for coding and 100/100 for reasoning, against Claude Sonnet 5's 95/100 and 92/100.

Capability breakdown

Across the five core benchmark categories, here is how Claude Fable 5 and Claude Sonnet 5 stack up head to head:

coding
100
95
reasoning
100
92
data extraction
97
92
creative tasks
98
91
vision/multimodal
96
90

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 Sonnet 5 runs about $57.20 — Claude Sonnet 5 saves roughly $228.80 (80%) 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.

Claude Fable 5 and Claude Sonnet 5 were released within 0 months of each other, so they are competing on the same evaluations under roughly the same conditions. That makes a direct benchmark comparison meaningful here in a way it usually is not — neither model has the advantage of being measured on a newer, easier set of tests.

Context is effectively a tie: 1.0M against 1.0M. Neither model unlocks a document size the other cannot handle, so this axis should not enter the decision. If you were hoping context would break the tie for you, it will not.

Latency separates them: Claude Sonnet 5 scores 88/100 against 55/100 for Claude Fable 5, a 33-point gap. That matters for anything a person waits on — chat, autocomplete, interactive tools. For batch and background work it does not, and trading latency for capability there is usually the right call.

Claude Fable 5 is 5.0x the price of Claude Sonnet 5. Reserve it for the requests that actually need it and route the rest to Claude Sonnet 5 — that hybrid beats either model used alone on cost per useful answer.

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 terms beyond the list price, per 1M tokens
Pricing termClaude Fable 5Claude Sonnet 5
List price (input / output)$10.00 / $50.00$2.00 / $10.00
Cached input$1.0010% of the input price$0.2010% of the input price
Batch API50% off input and output50% off input and output
Long promptsNo surcharge across the 1M windowNo surcharge across the 1M window
Input with 80% cache hits$2.80$0.56

With 80% of input served from the cache, Claude Sonnet 5 costs 80% less than Claude Fable 5 for the same input text, counting each model's tokenizer.The tokenizer factor for Claude Fable 5, Claude Sonnet 5 is our estimate until it is measured.

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

CategoryClaude FableClaude SonnetWinner

Coding

100
95
A

Reasoning

100
92
A

Extraction

97
92
A

Creative

98
91
A

Vision

96
90
A
Claude Fable 5: 5 wins
Claude Sonnet 5: 0 wins
Claude Fable 5 leads overall

Speed Score

55/100vs88/100
ClaudeClaude

Context Window

1000Kvs1000K
ClaudeClaude

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!"

4 tokens
Claude Fable 5
$5.72
Claude Sonnet 5
$1.14

Business email

One typical email (~200 words)

~270 tokens
Claude Fable 5
$386.10
Claude Sonnet 5
$77.22

Code file

50-line Python script

~400 tokens
Claude Fable 5
$572.00
Claude Sonnet 5
$114.40

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 Sonnet 5, 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_tokens

Every 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

30M tokens
Prompt 70%Completion 30%

Claude Fable 5

$943.80/mo

$11,325.60/yr

$10.00/M input$50.00/M output
Cheaper

Claude Sonnet 5

$188.76/mo

$2,265.12/yr

$2.00/M input$10.00/M output

Annual Savings

$9,060.48 saved per year

Claude Sonnet 5 cheaper · $755.04/mo

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