Lubricant cost to run

Negative price, rate, or hours fail with invalid_input and are not billed.

What lubricant cost to run means and how the yearly figure is built

Multiply them and you get yearly spend in the same currency as the price: annual_cost equals lubricant_price times consumption_rate times operating_hours. The implied annual volume is consumption_rate times operating_hours, which is useful when the stores manager needs to know how many drums to order, not only how much cash to reserve. A negative number is never a physical price, rate, or hour count, so it fails as invalid_input instead of producing a refund that nobody should book.

Input contract, response shape, and error behaviour

Any negative value fails with a message that lubricant price, consumption rate, and operating hours cannot be negative; those failures are not billed. POST a JSON body with three required finite non-negative numbers: lubricant_price, the unit price of the oil or grease; consumption_rate, volume or mass consumed per operating hour in the same unit; and operating_hours, hours the lubricated assets will run in the planning year. Each field may arrive as a JSON number or as a numeric string. Aliases price, unit_price, cost_per_unit, and price_per_unit map to lubricant_price; rate, consumption, usage_rate, and volume_per_hour map to consumption_rate; hours, annual_hours, hours_per_year, and operating_hrs map to operating_hours. Missing fields, empty strings, NaN, and Infinity fail with invalid_input naming the field. Magnitude ceilings keep results finite on a Worker isolate: lubricant_price at most one billion, consumption_rate at most one million, operating_hours at most one hundred million (enough for a large fleet total). On success the body echoes the three cleaned inputs, returns annual_volume as consumption_rate times operating_hours, returns annual_cost as lubricant_price times that volume, restates formula as annual_cost = lubricant_price × consumption_rate × operating_hours, and sets method to lubricant_cost_to_run. Worked example you can pin: lubricant_price eight point five, consumption_rate zero point zero two, operating_hours two thousand yields annual_volume forty and annual_cost three hundred forty. A second pin: twelve point four, zero point zero one five, one thousand eight hundred yields annual_volume twenty-seven and annual_cost three hundred thirty-four point eight. Successful API calls use prepaid KIT balance at the published $0.002 base price per item. Identical inputs always yield identical JSON.

Where a deterministic lubricant cost to run calculator earns its keep

Club secretaries and gym operators need a yearly lube line they can drop into a budget without reverse-engineering a vendor spreadsheet that was never designed as an API. Keep requests small, pin the rounded annual_cost values in tests, and you get reproducible lubricant-program figures for LMS quizzes, member portals, and edge workers. This landing is for people searching for lubricant cost to run, annual lubrication program cost, or yearly oil and grease spend from price and hours. It is not a viscosity grade table, not an ISO relubrication-interval chart, and not a multi-SKU purchase-order system.