GPT-6.1 Terra vs Gemini 3.8 Flash: API cost comparison
For a typical chatbot (1,500 input + 400 output tokens, 100,000 requests a month), Gemini 3.8 Flash is 23% cheaper: $268 vs $350 for GPT-6.1 Terra. Paste your own prompt below to compare the exact cost of your workload.
0 characters0 words0 tokens (GPT o200k)
| Model | Per month |
|---|---|
| GPT-6.1 Terra | |
| Gemini 3.8 Flash |
≈ = estimated token count: only OpenAI publishes its tokenizer. Claude counts use Anthropic’s published ratios; use the count_tokens API for an exact number.
Price per million tokens
USD, standard tier. Prices checked on October 28, 2026.
| GPT-6.1 Terra | Gemini 3.8 Flash | |
|---|---|---|
| Input | $1 | $0.75 |
| Output | $5 | $3.75 |
| Cached input | $0.05 | $0.075 |
| Cache write (5 min) | Not charged separately | Not charged separately |
| Long prompts | Above 272K tokens: $2 / $7.5 | Same price at any length |
| Batch API | 50% off | 50% off |
| Provider | OpenAI (GPT) | Google (Gemini) |
Gemini 3.8 Flash: Price doubles in January 2027 ($1.50 / $7.50).
Monthly cost for common workloads
| Workload | GPT-6.1 Terra | Gemini 3.8 Flash |
|---|---|---|
| Chatbot 1,500 input + 400 output tokens, 100,000 requests a month | $350 | $268 |
| Document Q&A (RAG) 8,000 input + 500 output tokens, half the input cached, 20,000 requests a month | $134 | $107 |
| Long-document summary 150,000 input + 2,000 output tokens, 1,000 requests a month | $160 | $126 |
| Bulk classification (Batch API) 500 input + 20 output tokens, 1 million requests a month, Batch API where available | $300 | $234 |
Token counts are converted per model: the same text becomes a different number of tokens on each provider (see below). The cheaper option in each row is highlighted.
Frequently asked questions
Is GPT-6.1 Terra cheaper than Gemini 3.8 Flash?
Per million tokens, GPT-6.1 Terra costs $1 / $5 (input / output) and Gemini 3.8 Flash costs $0.75 / $3.75. For a typical chatbot workload (1,500 input + 400 output tokens, 100,000 requests a month), Gemini 3.8 Flash is 23% cheaper: $268 vs $350 for GPT-6.1 Terra. Token counts differ between providers, so compare the cost of the same prompt rather than the price per token.
How much do GPT-6.1 Terra and Gemini 3.8 Flash cost per million tokens?
GPT-6.1 Terra: $1 / $5 for input / output, $0.05 for cached input. Gemini 3.8 Flash: $0.75 / $3.75, $0.075 for cached input. Prices in US dollars, standard tier, checked on October 28, 2026.
Do GPT-6.1 Terra and Gemini 3.8 Flash count tokens the same way?
GPT-6.1 Terra's tokenizer is not published; we use the o200k count, which is close for newer OpenAI models. Gemini 3.8 Flash's tokenizer is not published. We estimate about 1.05× the GPT o200k count for the same text.
Do GPT-6.1 Terra and Gemini 3.8 Flash have a Batch API discount?
Both do: GPT-6.1 Terra gets 50% off and Gemini 3.8 Flash 50% off for requests sent through the Batch API, which may take up to 24 hours.
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