API token cost basics
An API/token cost estimate is clearer when it separates input tokens, output tokens and request-level fees when a provider charges for them differently. Some providers also price cached input, batch processing, audio, images or tool use separately. That means a generic calculator works best with user-entered rates unless it has a dated provider integration.
The safe formula
Total API cost = input tokens x input rate + output tokens x output rate + requests x request rate
The rate unit must match the token unit. If the provider lists prices per one million tokens, divide the token count by one million before multiplying by the listed price.
Energy and device cost basics
Energy cost tools usually multiply consumption by price per kWh. The hard part is not the arithmetic; it is choosing a realistic consumption estimate, duty cycle and electricity price. Appliance labels, utility tariffs and charging losses can all change the result.
Common mistakes
- Using per-million-token prices as if they were per-token prices.
- Mixing GB and GiB in storage or bandwidth calculations.
- Ignoring output tokens, which can be more expensive than input tokens for some AI APIs.
- Using old provider pricing without a visible review date.
- Forgetting taxes, minimum charges, regional pricing, discounts or volume tiers.
Energy and technology cost examples
Electricity cost is power x time x price. A 1,500 W appliance running for 2 hours uses 3 kWh. At 0.25 per kWh, the direct energy cost is 0.75 before fixed fees, taxes or time-of-use pricing. A 10 W standby load running all year uses about 87.6 kWh because 0.01 kW x 8,760 hours = 87.6.
For data and hosting estimates, distinguish storage from transfer. A 50 GB backup stored for one month is a capacity question; downloading the same backup 20 times is a 1,000 GB transfer question. Cost calculators are clearer when they label both because providers often price them differently.
Use the calculators
- API and Token Cost Calculator
- Cloud Storage Cost Calculator
- Appliance Energy Cost Calculator
- EV Charging Time Calculator
- Energy and Technology Cost Formulas
FAQ
Why do API cost estimates differ from invoices?
Invoices may include cached-token rules, batch discounts, tool charges, taxes, regional pricing, minimums or model-specific rates that were not entered in the calculator.
Should I use GB or GiB?
Use the unit your provider uses. GB is decimal, while GiB is binary. Mixing them can create avoidable differences in storage and bandwidth estimates.
Are provider prices current in the calculator?
No, unless a page explicitly says live pricing is integrated. For API and cloud costs, confirm rates on the official provider pricing page.
References
- OpenAI API pricing documentation, accessed 2026-05-16. Use the live page for current model-specific prices.
- U.S. Department of Energy: estimating appliance energy use, accessed 2026-05-16.
- NIST: SI units, accessed 2026-05-16.
Last reviewed: 2026-05-16.