Which is cheaper, Claude Opus 4.5 (latest) or GPT-Realtime-2.1?

Claude Opus 4.5 (latest), at $34.34 per million tokens against $36 for GPT-Realtime-2.1, three parts input to one part output, read on 16 Sept 2026.

Where is each one cheapest?

Claude Opus 4.5 (latest): $34.34 at Poe. GPT-Realtime-2.1: nobody goes below the maker's own price with a reason we can point at, so $36 is the number to beat.

Can I buy both from one provider?

Yes. 3 providers sell both: FastRouter, LLM Gateway, Vercel AI Gateway. The cheapest of them for the two together is FastRouter.

Which holds more context?

Claude Opus 4.5 (latest), at 200k tokens against 128k.

Claude Opus 4.5 (latest) vs GPT-Realtime-2.1.

model vs model · prices as of 16 Sept 2026

GPT-Realtime-2.1 takes 3 of 5 rounds against Claude Opus 4.5 (latest). Claude Opus 4.5 (latest) counters on price: $34.34 per million tokens against $36, for 200k context instead of 128k.

Anthropic

Claude Opus 4.5 (latest)

$34.34/M tokens

cheapest we can explain, at Poe · $3.86 per 1,000 pages

200k context · tool calling · reads images

Poe ↗

OpenAIwins 3 rounds

GPT-Realtime-2.1

$36/M tokens

OpenAI list price, nothing below it is accounted for · $3.84 per 1,000 pages

128k context · tool calling · reads images

List price in (lower wins)

$5/M

$4/M

List price out (lower wins)

$25/M

$24/M

Cheapest we can explain (lower wins)

$34.34/M at Poe

none below list

Standard price (lower wins)

$40/M

$36/M

Cost per 1,000 pages (lower wins)

$3.86

$3.84

Context

200k tokens

128k tokens

Open weights

Tool calling

yes

Structured output

yes

Reads images

yes

Reasoning

yes

Released

24 Nov 2025

6 Jul 2026

Providers selling it

Price we measure against

the maker's own

Trains on your prompts (no is better)

not stated

no provider to check

Providers selling both · 3

FastRouter$40 / $36
LLM Gateway$40 / $36
Vercel AI Gateway$40 / $36

Claude Opus 4.5 (latest) then GPT-Realtime-2.1, per million tokens

Go further

open in the compare tool →every price for Claude Opus 4.5 (latest)every price for GPT-Realtime-2.1

Add a third or fourth model, or switch the weighting, in the tool.

What moved in the last seven days

Claude Opus 4.5 (latest)Nous Portal$4 / $20 $5 / $2525% dearer · 16 Sept 2026

Frequently asked

Which is cheaper, Claude Opus 4.5 (latest) or GPT-Realtime-2.1?: Claude Opus 4.5 (latest), at $34.34 per million tokens against $36 for GPT-Realtime-2.1, three parts input to one part output, read on 16 Sept 2026.
Where is each one cheapest?: Claude Opus 4.5 (latest): $34.34 at Poe. GPT-Realtime-2.1: nobody goes below the maker's own price with a reason we can point at, so $36 is the number to beat.
Can I buy both from one provider?: Yes. 3 providers sell both: FastRouter, LLM Gateway, Vercel AI Gateway. The cheapest of them for the two together is FastRouter.
Which holds more context?: Claude Opus 4.5 (latest), at 200k tokens against 128k.

Prices exclude tax and are per million tokens, read 16 Sept 2026 from each provider's own catalog. The standard price blends three parts input to one part output; a page is 600 tokens in and 60 out. Bars are scaled to the larger value in each row.