WattCost Energy Cost API

The same engine that powers our calculators, available as a simple JSON API. Build appliance running-cost features into your own product without reinventing the math.

POST /api/v1/cost

Authenticate with an API key via the Authorization header or x-api-key. Use demo-key to try it.

curl -X POST https://www.howmuchtorun.com/api/v1/cost \
  -H "Authorization: Bearer demo-key" \
  -H "Content-Type: application/json" \
  -d '{"watts":1500,"hoursPerDay":8,"pricePerKwh":0.17,"daysPerYear":120}'

Paid plans

The demo key is rate-limited and for evaluation only. Production keys with higher limits and SLA are billed monthly. Checkout via Stripe is activated in the next rollout — contact us to get on the early list.