Free tool

LLM API cost calculator

Tell us how much you send and receive. We will estimate your monthly cost across every model, ranked from cheapest to most expensive.

Prompt + system + context. ~¾ word per token.
What the model generates back.
Reuses repeated context at the cached input rate where a provider offers it.
Quick presets
Cheapest model for this workload
vs a flagship (GPT-5.4)
potential monthly saving
ModelProviderPer requestMonthly cost

List prices per 1M tokens, verified 2026-06-26. Estimates exclude image/audio tokens, batch discounts and free tiers.

How to estimate your LLM API cost

Every token-based API bills you twice: once for the input (everything you send — the prompt, system message and any context or documents) and once for the output (what the model writes back). Output is usually 2–5× more expensive than input, so the single biggest lever on your bill is how much the model generates.

The formula is simple:

monthly cost = requests × ((input_tokens × input_price) + (output_tokens × output_price)) / 1,000,000

Want the per-model numbers without the math? See the full LLM API price comparison or the cheapest LLM APIs guide.