Cost estimation for LLM API usage.
Prices are stored as USD per 1M tokens for (input, output). Only
models with well-known pricing are listed; unknown models return
:unknown.
Example
iex> Candil.Cost.estimate("gpt-4o", 1000, 500)
{:ok, 0.00775}
iex> Candil.Cost.estimate("unknown-model", 1000, 500)
:unknownSummary
Functions
Estimates the USD cost for a model and token counts.
Estimate cost for a (provider, model, input_tokens, output_tokens)
tuple. Returns {:ok, cost_usd} on success, :unknown if the
model is not in the pricing table, or {:error, reason} if the
inputs are invalid.
Formats a USD price as a human-readable string.
Returns the model names with known pricing.
Functions
@spec estimate(String.t(), non_neg_integer(), non_neg_integer()) :: {:ok, float()} | :unknown
Estimates the USD cost for a model and token counts.
@spec estimate(atom() | String.t(), String.t(), non_neg_integer(), non_neg_integer()) :: {:ok, float()} | :unknown | {:error, term()}
Estimate cost for a (provider, model, input_tokens, output_tokens)
tuple. Returns {:ok, cost_usd} on success, :unknown if the
model is not in the pricing table, or {:error, reason} if the
inputs are invalid.
Emits [:candil, :cost, :estimate] telemetry on every call (even
for unknown models, with cost_usd: 0.0).
Formats a USD price as a human-readable string.
Examples:
- 0.00775 → "$0.0078"
- 1.50 → "$1.50"
- 1500.0 → "$1.5K"
- 1_500_000 → "$1.5M"
Negative prices are formatted with a leading minus sign.
Examples
iex> Candil.Cost.format_price(0.0075)
"$0.0075"
iex> Candil.Cost.format_price(1500.0)
"$1.5K"@spec known_models() :: [String.t()]
Returns the model names with known pricing.