# GPT-6.1 Terra vs Kimi K3.1 Pro

GPT-6.1 Terra is the cheaper of the 2: for the same tokens, 3 read for each 1 written, Kimi K3.1 Pro costs 2 times as much. Below are both price lists, what 8 everyday jobs cost a month on each, and how many tokens the same text takes on each, which can change the answer.

- Page, with a calculator for your own job: https://tecyfy.com/prices/compare/gpt-6-1-terra-vs-kimi-k3-1-pro
- Makers: GPT-6.1 Terra from OpenAI, Kimi K3.1 Pro from Moonshot AI

## Price per million tokens, in US dollars

| | GPT-6.1 Terra | Kimi K3.1 Pro |
| --- | --: | --: |
| Input | $1 | $2 |
| Cached input | $0.05 | $0.20 |
| Cache write | $1.25 | $2 |
| Output | $5 | $10 |
| Blend, 3 read for each 1 written | $2 | $4 |
| Batch input | $0.50 | not listed |
| Batch output | $2.50 | not listed |
| Long prompt input (above 272K on GPT-6.1 Terra) | $2 | $2 |
| Long prompt output | $7.50 | $10 |
| Context window, tokens | 1.05M | 1.05M |
| Capability score (Epoch Capabilities Index; GPT-5 is 150) | not listed | not listed |
| Longest answer, tokens | 128K | not listed |

## The same text, counted by each maker

Our lesson "How AI writes" (https://tecyfy.com/learn/how-ai-works/how-ai-writes), about 1,700 words of English:

- GPT-6.1 Terra: about 2,100 tokens. GPT-5.6 is counted with o200k_base, the tokenizer OpenAI publishes for it, so its count is exact. OpenAI has not published the tokenizer of GPT-6, so its count is the same o200k_base figure, marked as about.
- Kimi K3.1 Pro: about 2,100 tokens. Counted with the tokenizer Moonshot AI publishes with Kimi K3, the model its API serves.

## What 8 everyday jobs cost a month on each

Each job at its usual runs a day, for 30 days, at the standard price.

| Job | Tokens in, out, runs a day | GPT-6.1 Terra | Kimi K3.1 Pro |
| --- | --- | --: | --: |
| A chat question | 300, 500, 100 | $8.40 | $16.80 |
| A hard question, with thinking | 300, 1,400, 100 | $21.90 | $43.80 |
| A long report, summarised | 60,000, 2,000, 20 | $42.00 | $84.00 |
| A 40-turn agent task | 2,800,000, 40,000, 10 | $182 | $439 |
| A support bot's reply | 4,000, 300, 2,000 | $216 | $444 |
| Sort a message into a category | 250, 5, 50,000 | $413 | $825 |
| Read an invoice into fields | 1,500, 250, 1,000 | $82.50 | $165 |
| Review a pull request | 25,000, 4,500, 50 | $71.25 | $143 |

## Questions

### Which is cheaper, GPT-6.1 Terra or Kimi K3.1 Pro?

GPT-6.1 Terra is cheaper: $1 per million tokens read and $5 per million written, against $2 and $10 on Kimi K3.1 Pro. On a mix of 3 tokens read for each 1 written, Kimi K3.1 Pro costs 2 times as much.

### What does a support bot cost a month on GPT-6.1 Terra and Kimi K3.1 Pro?

At 2,000 replies a day, each reading 4,000 tokens (50 percent of them from cache) and writing 300, it costs $216 a month on GPT-6.1 Terra and $444 on Kimi K3.1 Pro: Kimi K3.1 Pro costs 2.1 times as much for this job.

### What does an AI agent task cost on GPT-6.1 Terra and Kimi K3.1 Pro?

One 40-turn task that reads 2,800,000 tokens in all, 90 percent of them from cache, and writes 40,000, costs 61 cents on GPT-6.1 Terra and $1.46 on Kimi K3.1 Pro. At 10 tasks a day that is $182 and $439 a month.

### Which has the larger context window, GPT-6.1 Terra or Kimi K3.1 Pro?

GPT-6.1 Terra, with 1.05M tokens against 1.05M on Kimi K3.1 Pro. The window holds your instructions, the files you attach, the conversation so far and the answer, all at once.

### Does the same text take the same number of tokens on GPT-6.1 Terra and Kimi K3.1 Pro?

No. Our lesson "How AI writes", 1,700 words long, is about 2,100 tokens on GPT-6.1 Terra and about 2,100 on Kimi K3.1 Pro. Each maker cuts text its own way, and every extra token is paid for at the model's price.

### Can I pay less on GPT-6.1 Terra and Kimi K3.1 Pro for work that can wait?

On GPT-6.1 Terra only: with a batch, where you collect the answers later, it costs $0.50 per million tokens read and $2.50 written. Moonshot AI's price page lists no batch price for Kimi K3.1 Pro.

## Sources

- [OpenAI: API prices](https://developers.openai.com/api/docs/pricing)
- [Moonshot AI: API prices](https://platform.kimi.ai/docs/pricing/chat)

## Other comparisons

- [GPT-6.1 Terra vs GPT-6 Sol](https://tecyfy.com/prices/compare/gpt-6-1-terra-vs-gpt-6-sol.md)
- [GPT-5.6 Sol vs GPT-6.1 Terra](https://tecyfy.com/prices/compare/gpt-5-6-sol-vs-gpt-6-1-terra.md)
- [GPT-5.6 Terra vs GPT-6.1 Terra](https://tecyfy.com/prices/compare/gpt-5-6-terra-vs-gpt-6-1-terra.md)
- [GPT-5.6 Luna vs GPT-6.1 Terra](https://tecyfy.com/prices/compare/gpt-5-6-luna-vs-gpt-6-1-terra.md)
- [GPT-5.5 vs GPT-6.1 Terra](https://tecyfy.com/prices/compare/gpt-5-5-vs-gpt-6-1-terra.md)
- [GPT-5.5 pro vs GPT-6.1 Terra](https://tecyfy.com/prices/compare/gpt-5-5-pro-vs-gpt-6-1-terra.md)