How do you calculate inventory coverage in days?

Divide usable inventory on hand by average daily demand, then divide by the safety multiplier. With 1,200 kg, 85 kg/day and a 1.1x multiplier: 1,200 / 85 = 14.12 days raw, divided by 1.1 = 12.83 protected days.

What is the difference between protected and unprotected days here?

Unprotected days (14.12) is the raw on-hand-over-demand figure. Protected days (12.83) applies the 1.1x safety multiplier to reserve buffer for variability, so it is the number you plan reorders against.

What is a good days-of-supply target for CAM precursor?

It depends on feedstock lead time, but many CAM plants hold 10-30 days of critical precursor to cover resupply windows and qualification holds. The 12.83 protected days in the example is on the lean side if lead times are long.

How does the safety coverage multiplier work?

It shrinks raw coverage to a conservative figure: a 1.1x multiplier means you plan as if you have about 9% fewer days than the average implies, reserving that slack for demand spikes and quality holds. A larger multiplier yields fewer protected days.

Why use average daily demand instead of peak demand?

Average keeps the base calculation simple and comparable; the safety multiplier is where you account for peaks. If your demand is highly variable, raise the multiplier rather than swapping in peak demand.

Does this account for material in quality hold?

Only if you exclude held material from the usable inventory input. Enter only release-eligible kilograms as usable inventory so held lots do not inflate your coverage.

Cathode Active Material & Precursor Manufacturing calculator

Inventory Coverage Calculator

Inventory coverage converts kilograms of cathode active material or precursor on hand into days of supply, then derates that by a safety multiplier to give a conservative, protected coverage figure. CAM and pCAM supply chains are exposed to long feedstock lead times and tight cell-plant delivery windows, so planners track coverage in days rather than raw tonnage to know how long they can keep feeding the line if resupply slips. The safety multiplier builds a buffer for demand variability and qualification holds, so the protected number is the one you actually plan against. It is a core input to reorder timing and to commitments made to downstream cell manufacturers.

What this calculator does

Estimate adjusted days of coverage for CAM, precursor, metal sulfate, lithium source, or dopant inventory using stock on hand, daily demand, and a safety multiplier.
Use it when inventory coverage in cathode active material and precursor manufacturing is being sized for a buffer or safety stock review.
It divides usable inventory on hand by average daily demand to get raw coverage days, then divides by a safety multiplier to give protected days of supply.

Formula used

Unadjusted coverage days = usable battery-material inventory on hand ÷ average daily material demand
Adjusted inventory coverage = unadjusted coverage days ÷ safety coverage multiplier

Inputs explained

Usable battery-material inventory on hand:
Average daily material demand:
Safety coverage multiplier:

How to use the result

Use it for reorder planning, for stating how many days the line can run on hand, or for stress-testing coverage against a demand spike via the safety multiplier.
It assumes flat average daily demand; a CAM line with lumpy batch consumption or a demand spike can run out faster than the average-based days suggest.

Common questions

How do you calculate inventory coverage in days? Divide usable inventory on hand by average daily demand, then divide by the safety multiplier. With 1,200 kg, 85 kg/day and a 1.1x multiplier: 1,200 / 85 = 14.12 days raw, divided by 1.1 = 12.83 protected days.
What is the difference between protected and unprotected days here? Unprotected days (14.12) is the raw on-hand-over-demand figure. Protected days (12.83) applies the 1.1x safety multiplier to reserve buffer for variability, so it is the number you plan reorders against.
What is a good days-of-supply target for CAM precursor? It depends on feedstock lead time, but many CAM plants hold 10-30 days of critical precursor to cover resupply windows and qualification holds. The 12.83 protected days in the example is on the lean side if lead times are long.
How does the safety coverage multiplier work? It shrinks raw coverage to a conservative figure: a 1.1x multiplier means you plan as if you have about 9% fewer days than the average implies, reserving that slack for demand spikes and quality holds. A larger multiplier yields fewer protected days.
Why use average daily demand instead of peak demand? Average keeps the base calculation simple and comparable; the safety multiplier is where you account for peaks. If your demand is highly variable, raise the multiplier rather than swapping in peak demand.

Last reviewed 2026-05-12.