Which is more cost-effective, Claude Sonnet 5 or o3-mini?

Based on 1M input + 1M output tokens, Claude Sonnet 5 costs $12.00/month versus o3-mini at $5.50/month. The cheaper option depends on your token volume and prompt-to-completion ratio. Use the interactive calculator on this page to enter your exact usage.

How accurate is this cost comparison?

List prices come from each provider's own pricing page and every model page shows when they were last verified. The capability scores are iOPTERA's editorial composites — informed by public benchmarks, not benchmark results themselves; the methodology page explains how they are set.

Which model scores higher on benchmarks?

Claude Sonnet 5 scores 95 in coding and 92 in reasoning benchmarks. o3-mini scores 88 in coding and 93 in reasoning. See the full 5-category breakdown in the Benchmark Comparison section above.

What are the context window sizes of Claude Sonnet 5 and o3-mini?

Claude Sonnet 5 supports a 1.0M-token context window while o3-mini supports 200K tokens. A larger context window lets you process more text in a single API call.

Which model is faster for real-time applications?

Claude Sonnet 5 has a speed score of 88/100 and o3-mini scores 78/100 on our latency benchmark. For interactive chatbots and low-latency tasks, the higher speed score is preferable.

Can I calculate costs for my specific token volume?

Yes. Use the interactive cost calculator on this page. Enter your monthly token volume and adjust the prompt-to-completion ratio. You can also use presets for common scenarios like Customer Support Bots (~30M tokens/month) or Document Summarizers (~15M tokens/month).

Cost and performance comparison

Claude Sonnet 5 vs o3-mini

Model AAnthropic

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

Model BOpenAI

o3-mini

Capability score (editorial)93/100

Cost / 1M Tokens: $2.09; 70% in · 30% out mix
Value Index (score÷cost): 44.5; Higher = better value

Speed: 78/100
Context: 200K
Tier: Smart Tier

List price from the OpenAI pricing page, verified September 30, 2026.

Check the source

How we verify prices

In-depth analysis

Claude Sonnet 5 vs o3-mini: Detailed Comparison

Claude Sonnet 5 is Anthropic's mid-range-tier language model with a 1.0M-token context window, excelling at coding. o3-mini from OpenAI is a mid-range-tier model supporting 200K tokens in context, with standout performance in reasoning.

Claude Sonnet 5 costs 3.0x what o3-mini does for the same text. That is a steep premium, and it buys a 6-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 Sonnet 5 is priced at $2.00/M input tokens and $10.00/M output tokens. o3-mini costs $1.10/M input and $4.40/M output.

Claude Sonnet 5 turns the same text into about 43% more tokens than o3-mini, because their tokenizers differ — so comparing list prices per token understates what Claude Sonnet 5 costs. For the same text, split 70% input and 30% output and counted the way OpenAI's tokenizer counts it, Claude Sonnet 5 works out at about $6.29 per million tokens and o3-mini at $2.09. Every cost figure on this page includes that difference.

On iOPTERA's editorial scores, Claude Sonnet 5 leads with 95/100 for coding and 92/100 for reasoning, against o3-mini's 88/100 and 93/100.

Capability breakdown

Across the five core benchmark categories, here is how Claude Sonnet 5 and o3-mini stack up head to head:

coding

Claude Sonnet leads

reasoning

o3-mini leads

data extraction

Claude Sonnet leads

creative tasks

Claude Sonnet leads

vision/multimodal

Claude Sonnet leads

Best model by task

coding: Claude Sonnet 5 wins with 95/100
reasoning: o3-mini wins with 93/100
data extraction: Claude Sonnet 5 wins with 92/100
creative tasks: Claude Sonnet 5 wins with 91/100
vision/multimodal: Claude Sonnet 5 wins with 90/100

Estimated monthly cost at scale

For 10M + 2M tokens of text a month (counted the way OpenAI's tokenizer counts), Claude Sonnet 5 runs about $57.20 while o3-mini runs about $19.80 — o3-mini saves roughly $37.40 (65%) every month.

What actually decides it

Claude Sonnet 5 and o3-mini come from different labs, which means different tokenizers, different API shapes, and a second vendor relationship. The same English text does not produce the same token count on both, so a price-per-million comparison understates the difference — measure your own prompts on each before treating the headline rates as the full story.

Claude Sonnet 5 and o3-mini are 17 months apart, which is more than one generation in this market. Benchmark comparisons across that gap flatter the older model: it was measured against the evaluations that existed at the time. Treat o3-mini's scores as a floor for what it does well and be sceptical of a close-looking result.

The context gap is the largest single difference on this pair: Claude Sonnet 5 takes 1.0M tokens against 200K for o3-mini, 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 — 88/100 versus 78/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

Claude Sonnet 5 is 3.0x the price of o3-mini. Reserve it for the requests that actually need it and route the rest to o3-mini — 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 term	Claude Sonnet 5	o3-mini
List price (input / output)	$2.00 / $10.00	$1.10 / $4.40
Cached input	$0.2010% of the input price	—
Batch API	50% off input and output	—
Long prompts	No surcharge across the 1M window	—
Input with 80% cache hits	$0.56	—

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, OpenAI.

Capability scores

iOPTERA editorial scores across 5 categories — informed by public benchmarks, not measured by us

CategoryClaude Sonneto3-miniWinner

Coding

Reasoning

Extraction

Creative

Vision

Claude Sonnet 5: 4 wins

o3-mini: 1 wins

Claude Sonnet 5 leads overall

Speed Score

88/100vs78/100

Claudeo3-mini

Context Window

1000Kvs200K

Claudeo3-mini

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 Sonnet 5: $1.14
o3-mini: $0.44

Business email

One typical email (~200 words)

~270 tokens

Claude Sonnet 5: $77.22
o3-mini: $29.70

Code file

50-line Python script

~400 tokens

Claude Sonnet 5: $114.40
o3-mini: $44.00

Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both Claude Sonnet 5 and o3-mini, 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

Monthly Token Volume

30M tokens

Prompt / Completion Split

Prompt 70%Completion 30%

Claude Sonnet 5

$188.76/mo

$2,265.12/yr

$2.00/M input$10.00/M output

Cheaper

o3-mini

$62.70/mo

$752.40/yr

$1.10/M input$4.40/M output

Annual Savings

$1,512.72 saved per year

o3-mini cheaper · $126.06/mo

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