Which is more cost-effective, Claude Sonnet 5 or GPT-4o?

Based on 1M input + 1M output tokens, Claude Sonnet 5 costs $12.00/month versus GPT-4o at $12.50/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. GPT-4o scores 87 in coding and 90 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 GPT-4o?

Claude Sonnet 5 supports a 1.0M-token context window while GPT-4o supports 128K 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 GPT-4o scores 90/100 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 GPT-4o

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

GPT-4o

Capability score (editorial)90/100

Cost / 1M Tokens: $4.75; 70% in · 30% out mix
Value Index (score÷cost): 18.9; Higher = better value

Speed: 90/100
Context: 128K
Tier: Smart Tier

List price from the OpenAI pricing page, verified October 12, 2026.

Check the source

How we verify prices

In-depth analysis

Claude Sonnet 5 vs GPT-4o: Detailed Comparison

Claude Sonnet 5 is Anthropic's mid-range-tier language model with a 1.0M-token context window, excelling at coding. GPT-4o from OpenAI is a mid-range-tier model supporting 128K tokens in context, with standout performance in vision/multimodal.

This is a genuine tradeoff rather than a clear win. Claude Sonnet 5 leads by 10 points on combined coding and reasoning, and costs 25% more for the same text to do it. The margin is narrow enough that the answer depends on your workload: on tasks where the extra capability shows up, the premium pays for itself; on routine work it does not. Claude Sonnet 5 is priced at $2.00/M input tokens and $10.00/M output tokens. GPT-4o costs $2.50/M input and $10.00/M output.

Claude Sonnet 5 turns the same text into about 43% more tokens than GPT-4o, 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 GPT-4o at $4.75. 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 GPT-4o's 87/100 and 90/100.

Capability breakdown

Across the five core benchmark categories, here is how Claude Sonnet 5 and GPT-4o stack up head to head:

coding

Claude Sonnet leads

reasoning

Claude Sonnet leads

data extraction

Tie

creative tasks

GPT-4o leads

vision/multimodal

GPT-4o leads

Best model by task

coding: Claude Sonnet 5 wins with 95/100
reasoning: Claude Sonnet 5 wins with 92/100
creative tasks: GPT-4o wins with 92/100
vision/multimodal: GPT-4o wins with 95/100

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 GPT-4o runs about $45.00 — GPT-4o saves roughly $12.20 (21%) every month.

What actually decides it

Claude Sonnet 5 and GPT-4o 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 GPT-4o are 25 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 GPT-4o'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 128K for GPT-4o, roughly 7.8x. 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 — 90/100 versus 88/100. Neither model will feel noticeably quicker in an interactive product, so latency is not a reason to choose between them.

Neither model is the obvious answer. Claude Sonnet 5 leads on benchmarks, GPT-4o on cost, and the gap is small on both. Run the calculator above with your real token mix — for most workloads that decides it faster than any benchmark table will.

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	GPT-4o
List price (input / output)	$2.00 / $10.00	$2.50 / $10.00
Cached input	$0.2010% of the input price	$1.2550% of the input price
Batch API	50% off input and output	50% off input and output
Long prompts	No surcharge across the 1M window	—
Input with 80% cache hits	$0.56	$1.50

With 80% of input served from the cache, Claude Sonnet 5 costs 47% less than GPT-4o for the same input text, counting each model's tokenizer.The tokenizer factor for 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, OpenAI.

Capability scores

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

CategoryClaude SonnetGPT-4oWinner

Coding

Reasoning

Extraction

Tied

Creative

Vision

Claude Sonnet 5: 2 wins

GPT-4o: 2 wins

Speed Score

88/100vs90/100

ClaudeGPT-4o

Context Window

1000Kvs128K

ClaudeGPT-4o

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
GPT-4o: $1.00

Business email

One typical email (~200 words)

~270 tokens

Claude Sonnet 5: $77.22
GPT-4o: $67.50

Code file

50-line Python script

~400 tokens

Claude Sonnet 5: $114.40
GPT-4o: $100.00

Prices shown are for 100,000 runs of each workload — one run costs a fraction of a cent on both Claude Sonnet 5 and GPT-4o, 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

GPT-4o

$142.50/mo

$1,710.00/yr

$2.50/M input$10.00/M output

Annual Savings

$555.12 saved per year

GPT-4o cheaper · $46.26/mo

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