A system prompt plus eight turns of conversation, with the full history re-sent each turn, sums to ≈ 6,000 input tokens across the conversation. Eight replies ≈ 900 output tokens.
Cost = (input tokens ÷ 1M × input price) + (output tokens ÷ 1M × output price). Prices come from our daily-verified model data. Batch and cached-input discounts are not applied — they only ever make these numbers smaller.
“Needs chunking” means the model's context window can't hold this job in a single pass, so the real cost is higher than the figure shown and quality usually suffers.
Should you just pick the cheapest?
Chat bills quadratically, not linearly: every turn re-sends the whole history, so a sixteen-turn conversation costs roughly four times an eight-turn one rather than twice. Prompt caching targets exactly this and can cut the input side by up to 90% on a stable system prompt.
$0.0001 on Mistral: Mistral Nemo, the cheapest capable option, rising to $0.010 on Claude Sonnet 5 at the top end. GPT-5.6 Luna is the value pick at $0.0011 per run. The job is priced at 6,000 input and 900 output tokens — see the working below.
How did you work out the token count for this task?
A system prompt plus eight turns of conversation, with the full history re-sent each turn, sums to ≈ 6,000 input tokens across the conversation. Eight replies ≈ 900 output tokens.
What does this cost at 10,000 conversations a month?
$1.47 a month on Mistral: Mistral Nemo, $11.40 on GPT-5.6 Luna, and $105 on Claude Sonnet 5. Batch APIs typically halve these figures for work that can wait, and prompt caching cuts the input side further when the same context is reused.
Is the cheapest model the right choice for this task?
Chat bills quadratically, not linearly: every turn re-sends the whole history, so a sixteen-turn conversation costs roughly four times an eight-turn one rather than twice. Prompt caching targets exactly this and can cut the input side by up to 90% on a stable system prompt.
Are these prices current?
Yes. Every figure on this page is computed from our model pricing data, which is checked daily against each provider's official pricing page. When a provider changes a price, these numbers change with it.