When to reorder inventory.

Reorder point is the inventory level that triggers a new order. Formula: (daily usage × lead time) + safety stock. If you sell 100 units/day and lead time is 14 days, you need 1,400 units on hand when the reorder triggers, plus safety stock for demand variability. Running out before reorder arrives = stockout; ordering too early = excess carrying cost.

50 units/day average × 10-day lead time = 500 lead-time demand. + 7 days safety stock × 50 = 350. Reorder point = 850 units. When inventory hits 850 units, place the order. Inventory should arrive when stock reaches ~350 (safety stock buffer), giving protection against demand spikes or delivery delays.

Safety stock calibration: too little = frequent stockouts, lost sales, customer frustration. Too much = wasted carrying cost on rarely-used buffer. Statistical approach: safety stock = z-score × standard deviation of demand × √lead time. Most businesses set safety stock at 1-2 standard deviations (84-97.7% service level).

Quick example

With avg daily usage of 50 and lead time of 10 (plus safety stock of 7), the result is 850 units. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Avg Daily Usage, Lead Time (days), and Safety Stock (days). Not every input has equal weight. Flip one at a time toward extreme values to feel which ones move the needle most for your situation.

What's happening under the hood

Lead-time demand = daily usage × lead time. Safety stock = daily usage × safety days. Reorder point = lead-time demand + safety stock. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

What the score tells you

Headline financial numbers — income, savings, debt — each tell part of the story. This calculation stitches several together into a single read you can track over time. The value is in the direction, not the absolute number.

What this doesn't capture

The score is a composite of the inputs you provide. Life context — job security, family obligations, health, housing — doesn't appear in the math but shapes the real picture. Use the number as a prompt, not a verdict.