GPT-4o vs GPT-5.6 Terra
Whether moving to the current generation is cheaper as well as newer.
Side by side
| Attribute | GPT-4o | GPT-5.6 Terra |
|---|---|---|
| Input, per 1M tokens | $2.50 | $2.00 |
| Output, per 1M tokens | $10.00 | $12.00 |
| Context window | 128,000 | 1,050,000 |
| Provider | OpenAI | OpenAI |
| Tokenizer | o200k_base | o200k_base |
| Long-context tier | none | above 272,000 |
| Retires | no date announced | no date announced |
Which to choose
- Reading more than you write
- GPT-5.6 Terra $2 against GPT-4o $2.50 per million input tokens — a modest gap of 1.3x.
- Writing more than you read
- This flips the pair: GPT-4o is dearer on input but cheaper on output, $10 against $12. Which one costs less depends entirely on your answer length.
- Whole documents in one request
- GPT-4o stops at 128,000; GPT-5.6 Terra takes 1,050,000. Past the lower ceiling only GPT-5.6 Terra accepts the request, at any price.
- Past the long-context threshold
- The ranking inverts (GPT-5.6 Terra above 272,000): GPT-5.6 Terra wins below the line, GPT-4o above it at $2.50 against $4. Judging this pair on headline rates alone gives the wrong answer for large prompts.
- 10,000 in, 1,000 out
- $0.0350 on GPT-4o, $0.0320 on GPT-5.6 Terra. Over 10,000 such calls that is $30.00 in GPT-5.6 Terra's favour.
What this page does not tell you. Which model produces better answers. That depends on your task, and this site has no benchmark data — everything above is drawn from published pricing and specifications. Compare quality by running your own prompts through both.