AI API Cost Comparison Calculator
Model cost comparison with retries counted. A cheaper model that needs a second attempt on a fifth of requests is not a fifth cheaper, and the break-even retry rate is what decides the choice.
Also called: llm pricing comparison, model cost comparison.
Model B is cheaper. Model A costs $175,000.00 a month and model B $56,000.00 including a 0% retry rate, a difference of $119,000.00 or 68%. Model B stops being cheaper above a 212.5% retry rate.
How this is calculated
Both models are priced on the same token volumes. The retry rate is the input that makes this honest: a cheaper model that fails or produces unusable output some of the time costs its rate card plus the retries, and often plus a fallback to the expensive model. The break-even retry rate shown is where the two become equal, which is usually a lower number than people expect. Self hosting is a fixed cost against a variable one, so it wins only above a volume threshold and carries operational cost that no rate card shows.
a cheaper model that needs retries is not as cheap as its rate card suggests- r
- Retry rate
Method and limits
What it assumes
- Identical token volumes on both models, which different models rarely produce.
What it deliberately does not model
- Different models produce different output lengths for the same task, which this holds constant.
- Quality differences are not captured by any cost comparison.
- Self hosting cost excludes engineering time, which usually dominates.
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Frequently asked questions
- Is the cheaper model always cheaper?
- Only below the break-even retry rate. A model at a third of the price that needs two attempts on half of requests has given the saving back.
- When does self hosting pay?
- Above a volume threshold, and only if you exclude nothing. The infrastructure is the visible cost and the engineering time to run it reliably is usually larger.