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Cost and performance comparison

Claude 3.5 Sonnet vs Claude Sonnet 5.5

Model AAnthropic

Claude 3.5 Sonnet

Capability score (editorial)89/100
Cost / 1M Tokens
$6.60
70% in · 30% out mix
≈ $7.26 for the same text, tokenizer included
Value Index (score÷cost)
12.3
Higher = better value
Speed
95/100
Context
200K
Tier
Smart 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.

How we verify prices

Model BAnthropic

Claude Sonnet 5.5

Capability score (editorial)94/100
Cost / 1M Tokens
$4.40
70% in · 30% out mix
≈ $6.29 for the same text, tokenizer included
Value Index (score÷cost)
14.9
Higher = better value
Speed
91/100
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 3.5 Sonnet vs Claude Sonnet 5.5: Detailed Comparison

Claude 3.5 Sonnet is Anthropic's mid-range-tier language model with a 200K-token context window, excelling at creative tasks. Claude Sonnet 5.5 from Anthropic is a mid-range-tier model supporting 1.0M tokens in context, with standout performance in coding.

Price is not the deciding factor here. For the same text, Claude Sonnet 5.5 and Claude 3.5 Sonnet 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 3.5 Sonnet is priced at $3.00/M input tokens and $15.00/M output tokens. Claude Sonnet 5.5 costs $2.00/M input and $10.00/M output.

Claude Sonnet 5.5 turns the same text into about 30% more tokens than Claude 3.5 Sonnet, because their tokenizers differ — so comparing list prices per token understates what Claude Sonnet 5.5 costs. For the same text, split 70% input and 30% output and counted the way OpenAI's tokenizer counts it, Claude Sonnet 5.5 works out at about $6.29 per million tokens and Claude 3.5 Sonnet at $7.26. Every cost figure on this page includes that difference.

On iOPTERA's editorial scores, Claude Sonnet 5.5 leads with 97/100 for coding and 94/100 for reasoning, against Claude 3.5 Sonnet's 88/100 and 89/100.

Capability breakdown

Across the five core benchmark categories, here is how Claude 3.5 Sonnet and Claude Sonnet 5.5 stack up head to head:

coding
88
97
reasoning
89
94
data extraction
90
94
creative tasks
91
93
vision/multimodal
88
92

Best model by task

  • coding: Claude Sonnet 5.5 wins with 97/100
  • reasoning: Claude Sonnet 5.5 wins with 94/100
  • data extraction: Claude Sonnet 5.5 wins with 94/100
  • creative tasks: Claude Sonnet 5.5 wins with 93/100
  • vision/multimodal: Claude Sonnet 5.5 wins with 92/100

Estimated monthly cost at scale

For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), Claude 3.5 Sonnet runs about $66.00 while Claude Sonnet 5.5 runs about $57.20 — Claude Sonnet 5.5 saves roughly $8.80 (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 Sonnet 5.5 is the current entry; Claude 3.5 Sonnet 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 Sonnet 5.5 takes 1.0M tokens against 200K for Claude 3.5 Sonnet, 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 — 95/100 versus 91/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

With prices this close (13% apart), pick on fit rather than cost. Claude Sonnet 5.5 holds the benchmark edge; weigh that against where each one is weakest — coding and vision processing 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 terms beyond the list price, per 1M tokens
Pricing termClaude 3.5 SonnetClaude Sonnet 5.5
List price (input / output)$3.00 / $15.00$2.00 / $10.00
Cached input—$0.105% of the input price
Batch API—50% off input and output
Long prompts—No surcharge across the 1M window
Input with 80% cache hits—$0.48

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 3.5Claude SonnetWinner

Coding

88
97
B

Reasoning

89
94
B

Extraction

90
94
B

Creative

91
93
B

Vision

88
92
B
Claude 3.5 Sonnet: 0 wins
Claude Sonnet 5.5: 5 wins
Claude Sonnet 5.5 leads overall

Speed Score

95/100vs91/100
ClaudeClaude

Context Window

200Kvs1000K
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 3.5 Sonnet
$1.32
Claude Sonnet 5.5
$1.14

Business email

One typical email (~200 words)

~270 tokens
Claude 3.5 Sonnet
$89.10
Claude Sonnet 5.5
$77.22

Code file

50-line Python script

~400 tokens
Claude 3.5 Sonnet
$132.00
Claude Sonnet 5.5
$114.40

Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both Claude 3.5 Sonnet and Claude Sonnet 5.5, 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 3.5 Sonnet

$217.80/mo

$2,613.60/yr

$3.00/M input$15.00/M output
Cheaper

Claude Sonnet 5.5

$188.76/mo

$2,265.12/yr

$2.00/M input$10.00/M output

Annual Savings

$348.48 saved per year

Claude Sonnet 5.5 cheaper · $29.04/mo

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