★ Head-to-head

Claude Opus 5.5 vs Claude Sonnet 5.5: API Cost Comparison

The classic "do we really need the big model?" decision inside the Claude family.

Runs in your browser
No signup
Updated 7 Nov 2026

Claude Opus 5.5 and Claude Sonnet 5.5 pricing side by side
Side by side	Claude Opus 5.5 Anthropic	Claude Sonnet 5.5 Anthropic
Input / 1M	$4	$2
Output / 1M	$20	$10
Cached input / 1M	$0.20	$0.10
Batch discount	50% off	50% off
Context window	1M tokens	1M tokens
Long-prompt surcharge	None	None
Tier	Frontier	Mid-tier

Workload

Requests per day

Avg input tokens

tok

Avg output tokens

tok

Cached input

Repeated system prompt or docs

Batched requests

Jobs that can wait hours

Models

Anthropic

OpenAI

Google

Mistral

DeepSeek

$ per 1M tokens, input / output

Monthly cost · 30 days

Cheapest: $2,100; Claude Sonnet 5.5
Priciest: $4,200; Claude Opus 5.5
Spread: 2.0×; priciest vs cheapest

	Per request		Per 1K users / mo
Claude Sonnet 5.5Cheapest	$0.00700	$2,100	$1,050
Claude Opus 5.5	$0.0140	$4,200	$2,100

Per 1K users assumesrequests per user per day.

Where the money is

If 60% of your traffic is simple enough for Claude Sonnet 5.5, routing it there instead of Claude Opus 5.5 saves about $1,260/month.

Caching half your input on Claude Opus 5.5 (a shared system prompt or document) would cut about $1,140/month.

You're looking at $2,100–$4,200/month.

Most AI products I audit can cut that 30–60% with routing, caching and shorter prompts.

Get a cost-cutting audit

Cost at three traffic levels

Same request on both: 2,000 input tokens and 300 output tokens, no caching, no batch, 30-day month.

Monthly cost of Claude Opus 5.5 vs Claude Sonnet 5.5
Requests / day	Claude Opus 5.5	Claude Sonnet 5.5	Difference
1,000	$420	$210	$210
10,000	$4,200	$2,100	$2,100
100,000	$42,000	$21,000	$21,000

By request type:

Cost per 1,000 calls by request type, Claude Opus 5.5 vs Claude Sonnet 5.5
Per 1K calls	Claude Opus 5.5	Claude Sonnet 5.5
Classification or routing call	$1.80	$0.9000
Support chat reply	$11.00	$5.50
RAG answer over your docs	$32.00	$16.00
Long document summary	$180	$90.00

When to pick which

Claude Sonnet 5.5 is 2.0× cheaper on input tokens, which matters most for RAG and long prompts.
Claude Sonnet 5.5 is 2.0× cheaper on output tokens, which matters most for long answers, code generation and reasoning.
Cache reads are 2.0× cheaper on Claude Sonnet 5.5 ($0.10 vs $0.20 per 1M), so it pulls ahead when your prompts share a long fixed prefix.
Both offer 50% off for batch processing.

Claude Opus 5.5: Complex coding, multi-step agents and analysis where you need frontier quality at well under top-tier prices.

Claude Sonnet 5.5: The default for production chat, RAG and coding assistants: strong quality at a mid-tier price.

Verdict

Claude Sonnet 5.5 wins on price

2.0× cheaper

On price alone, Claude Sonnet 5.5 wins: about 2.0× cheaper than Claude Opus 5.5 for a typical request. Price is one input. Run both on 50 of your real prompts, compare the answers and the billed tokens, and route by difficulty if the quality gap only shows up on hard requests.

How the math works

Every provider bills input tokens (your prompt, system prompt and retrieved documents) and output tokens (the reply) separately, per million. Output is usually 4–5× the input price, so chatty apps are output-heavy and RAG apps are input-heavy.

cost per request = (fresh_in × input_price

+ cached_in × cached_price

+ out × output_price) / 1,000,000

× (1 − batched_share × batch_discount)

monthly = cost per request × requests per day × 30

Two adjustments are applied automatically. Introductory prices (currently on some Gemini models) are used until their end date. Long-prompt surcharges kick in when your average input crosses the provider's threshold: 272K tokens on current OpenAI models, 100K on Claude Haiku 5.5.

Not modelled: cache-write premiums, priority or fast tiers, regional surcharges, image and audio tokens, and reasoning tokens a model spends before answering (they bill as output, so add them to your output estimate if you use extended thinking).

Questions

Which is cheaper, Claude Opus 5.5 or Claude Sonnet 5.5?

For a typical request of 2,000 input and 300 output tokens, Claude Sonnet 5.5 is about 2.0× cheaper: $0.0140 per call on Claude Opus 5.5 vs $0.00700 on Claude Sonnet 5.5. At 10,000 requests a day that is $4,200 vs $2,100 a month.

Can I use both Claude Opus 5.5 and Claude Sonnet 5.5?

Yes, and many teams do. Put a thin routing layer in front of both: send the requests that need the stronger or larger-context model to it, and everything else to the cheaper one. Keep prompts provider-neutral so you can move traffic when prices change.

How often do Anthropic change prices?

Often enough that a comparison older than a few months is suspect. The prices on this page were verified on 7 Nov 2026 from each provider's own documentation, linked in the Sources section.

Sources

All prices are list prices from each provider's own documentation, standard tier, in USD, last verified on 7 Nov 2026. Providers change prices often; if a number here disagrees with the source, the source wins.

Claude Opus 5.5platform.claude.com
Claude Sonnet 5.5platform.claude.com

More from the workbench

01 · Plan & scopeMVP Cost EstimatorPick features and who builds it. Get an hour-by-hour estimate, not an agency teaser.03 · Money & fundraisingRunway & Burn CalculatorMonths of cash left, the date it hits zero, and whether you are default alive.04 · Money & fundraisingSaaS Metrics CalculatorsLTV, CAC, churn, NRR, burn multiple and more, each with the formula and benchmarks.

Fine print

Tools: on the house.
Engineer: by the hour.

Knowing your AI bill was free. Cutting it in half isn't, but I'm cheaper than the overspend.

I'm Himanshu, an AI and full-stack engineer. I build MVPs, AI agents and the growth plumbing around them for early-stage startups.

Hire me →My projects