Which is cheaper, GPT-4o or GPT-Realtime-2.1?

GPT-4o, at $16.63 per million tokens against $36 for GPT-Realtime-2.1, three parts input to one part output, read on 17 Sept 2026.

Where is each one cheapest?

GPT-4o: $16.63 at Jiekou. 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. One provider sells both: OpenAI. The cheapest of them for the two together is OpenAI.

Which holds more context?

Both hold 128k tokens in one call.

GPT-4o vs GPT-Realtime-2.1.

model vs model · prices as of 17 Sept 2026

GPT-4o takes 3 of 5 rounds against GPT-Realtime-2.1. It is also the cheaper of the two to run, at $16.63 per million tokens against $36.

OpenAIwins 3 rounds

GPT-4o

$16.63/M tokens

cheapest we can explain, at Jiekou · $2.00 per 1,000 pages

128k context · tool calling · reads images

Jiekou ↗

OpenAI

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)

$15/M

$24/M

Cheapest we can explain (lower wins)

$16.63/M at Jiekou

none below list

Standard price (lower wins)

$30/M

$36/M

Cost per 1,000 pages (lower wins)

$2.00

$3.84

Context

128k tokens

Open weights

Tool calling

yes

Structured output

yes

Reads images

yes

Reasoning

yes

Released

13 May 2024

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 · 1

OpenAI$30 / $36

GPT-4o then GPT-Realtime-2.1, per million tokens

Go further

open in the compare tool →every price for GPT-4o 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

GPT-4oNous Portal$2 / $8 $2.50 / $1025% dearer · 16 Sept 2026

Frequently asked

Which is cheaper, GPT-4o or GPT-Realtime-2.1?: GPT-4o, at $16.63 per million tokens against $36 for GPT-Realtime-2.1, three parts input to one part output, read on 17 Sept 2026.
Where is each one cheapest?: GPT-4o: $16.63 at Jiekou. 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. One provider sells both: OpenAI. The cheapest of them for the two together is OpenAI.
Which holds more context?: Both hold 128k tokens in one call.

Prices exclude tax and are per million tokens, read 17 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.