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Spare Parts Reorder Point Calculator

Estimate a whole-unit reorder trigger from average daily use, positive supplier lead time in days, and whole-unit safety stock. Formula: reorder point = ceiling(daily use × lead-time days + safety stock).

Example values are prefilled to demonstrate the calculation. Replace them with values for your product, package, equipment, and operating conditions.

Inputs

Demand, lead time, and safety stock

Range: at least 0

Enter average demand using the same inventory unit as safety stock. Choose calendar days or working/operating days, then convert supplier lead time to that same day basis; The prefilled demand rate and day basis are examples; use site data and one consistent day basis.

Range: at least 0 matching days

Enter positive supplier lead time in the same day basis used for average daily demand. Calendar-day demand requires calendar-day lead time; operating-day demand requires lead time converted to operating days.

Range: at least 0 inventory units

Enter non-negative whole inventory units held as the safety buffer. This value is user-supplied and is not statistically optimized.

Result

Valid
Expected demand during lead time
80.00 inventory units
Whole-unit reorder-point threshold
100 inventory units
Unrounded demand plus safety stock
100.00 inventory units
Interpretation and exclusions
Reorder trigger = demand during supplier lead time + user-entered safety stock; the result rounds up to a whole inventory unit. Compare against inventory position using the site's purchasing rules. Open orders, allocations, supplier variability, review cadence, and service-level optimization are not included.

Calculation

Expected demand during lead time
—
Unrounded demand plus safety stock
—
Whole-unit reorder-point threshold
—

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