Stock duration calculator
How many days a stock lasts at a known rate of use.
Fill in the fields and the result will appear here automatically.
Divides supplies by a constant daily use: feed, grain, fuel or consumables, not shares. The threshold in days sets how much cover you want left when ordering. Include delivery time and an extra buffer if that is your plan; the result locates your chosen reorder point but does not guarantee delivery.
How it works
Formula and logic
Duration = stock / daily use. With a positive threshold, reorder time = duration − threshold; a negative difference means that threshold is already breached. Zero stock means 0 days; negative stock and threshold are invalid.
Example
30 kg of feed used at 2 kg a day lasts 15 days. A 4-day reorder threshold means ordering in 11 days from now.
Fields and units
- Stock on hand — same chosen unit
- Daily use — same unit/day
- Safety buffer — days
How to use
- — Enter the stock you have, in whatever unit suits you.
- — Give the daily use in the same unit.
- — Optionally set a safety buffer in days.
- — Zero stock is allowed; daily use must be positive. A blank optional threshold means 0 days. Very small durations are shown without artificially raising them to 0.1 day.
Method and limitations
- Calculation method
- Formula and logic
- Limitation
- Constant consumption in matching units. Delivery, seasonality, spoilage and supplier availability are not forecast.
FAQ
What unit should the stock be in?
Any, as long as the stock and the daily use share it. Kilograms, litres, pieces — the calculator divides one by the other and works with the ratio.
What is the safety buffer in days?
The threshold is cover remaining when you order. To cover delivery time plus a desired remainder after arrival, include both in that one number. Delivery time is not added separately.
Is uneven consumption handled?
No, the rate is treated as constant. For seasonal peaks use the average rate of the peak period rather than the yearly one.
Is this about supplies or about shares?
Supplies: feed, grain, fuel, consumables. Financial securities are unrelated.