LLM API Cost Calculator
Turn request volume, prompt shape and cache hit rate into a monthly bill across the current GPT, Claude, Gemini and DeepSeek tiers. Prices are pre-filled with list rates (checked 2026-08-15) and every cell is editable, so your negotiated rate goes in as easily.
Monthly cost by model
| Model | Input $/M | Cached $/M | Output $/M | Monthly cost | Per 1k requests | vs cheapest |
|---|---|---|---|---|---|---|
| Claude Opus 5 Anthropic | — | — | — | |||
| Claude Sonnet 5 Anthropic | — | — | — | |||
| Claude Haiku 4.5 Anthropic | — | — | — | |||
| DeepSeek V4 Pro DeepSeek | — | — | — | |||
| DeepSeek V4 Flash DeepSeek | — | — | — | |||
| Gemini 3.7 Flash Google | — | — | — | |||
| Gemini 3.5 Flash Lite Google | — | — | — | |||
| GPT-5.6 Sol OpenAI | — | — | — | |||
| GPT-5.6 Terra OpenAI | — | — | — | |||
| GPT-5.3 Codex OpenAI | — | — | — | |||
| GPT-5.6 Luna OpenAI | — | — | — |
List prices as published by each vendor, checked 2026-08-15. Every number is editable — put your negotiated rate in.
Everything is calculated in your browser. No input leaves the page.
How the number is produced
Monthly cost = uncached input tokens × input rate + cached input tokens × cache-read rate + output tokens × output rate, with requests annualised over 30 days. Every rate is per million tokens, which is the unit all four vendors now quote in.
Two things get underestimated more than anything else. Output weight — output is priced 5 to 6× input almost everywhere, so a prompt change that trims an 800-token answer to 300 usually saves more than moving down a model tier. And cache hit rate — in RAG and agent workloads the system prompt and retrieved context repeat across turns, and going from 0% to 80% cuts the input side to a fifth. That is why it is a slider here rather than a buried assumption.
What is deliberately not modelled: batch and low-priority tiers, which typically halve both sides; long-context rates, which kick in above each vendor's threshold and cost roughly double; tool calls, web search and vector storage, all billed separately; and reserved capacity, private deployment or data-residency uplifts. This answers "what does this volume cost at per-token rates", not "what will the invoice say".
Where a vendor publishes no cache-read rate, the cached column is pre-filled with the full input rate — no assumed discount, erring towards over-estimating rather than under.