Supply Chain & InventoryFree calculatorPDF, Excel, Word export

EDI 830 Forecast Review Cycle Safety Stock Calculator

When customers send 830 planning schedules, your system only reacts when the forecast is loaded. The longer between loads, the longer your protection interval and the more safety stock you carry. This calculator shows the effect.

Your numbers

units/day
units

Variation of actual releases versus the average.

days

Supplier or production lead time.

7 days

A weekly 830 load is 7. A daily load is 1.

$
%

Capital, storage, handling and obsolescence.

Your results

Safety stock
203
Reorder point
2,243
Z score
1.6449
Protection interval
17 days
Lead time plus the time between forecast loads.
Safety stock value
$8,545
Safety stock carrying cost per year
$1,880

Assumes normally distributed, independent daily demand. Use actual release history to estimate the standard deviation.

Save results:

Safety stock by days between forecast loads

Sweeps Days between forecast loads from 0 to 30, holding your other inputs fixed.

Compare forecasts to actual releases

We can outline how to measure release variation per customer from your ERP. Optional.

Optional. The tool and every export work without this. No spam.

How to use it

Take average daily demand from shipments and calculate the standard deviation of daily actual releases against that average. Enter your lead time, the number of days between forecast loads into MRP, the service level and the unit cost. The tool returns safety stock, reorder point and the yearly carrying cost of that stock.

  • Use actual demand variation, not forecast error alone
  • Set review days to 0 only for continuous planning
  • Compare weekly, twice weekly and daily loads on the chart

Formula

The protection interval is lead time plus days between loads. Safety stock equals the Z score for the service level times daily standard deviation times the square root of the interval. Reorder point equals daily demand times the interval plus safety stock. This is the standard periodic review formulation, adapted to the cycle on which new customer forecasts reach planning.

Reading the result

Safety stock grows with the square root of time, so moving from a weekly to a daily forecast load cuts the interval from 17 days to 11 in the default case and trims safety stock by roughly a fifth. Multiply by unit cost and the carrying rate to see the yearly value of automating the 830 import and the MRP regeneration.

Common mistakes

Do not use the forecast quantity as demand variation: planning schedules often change, and what matters is the variation between what the customer actually releases and what you planned. Also avoid applying this to firm-horizon items where the customer commits quantities, since uncertainty is lower there.

Frequently Asked Questions

What is an 830 transaction?

The X12 830 is a planning schedule with release capability, used by customers to share forecasts and sometimes firm requirements. Shipping schedules, such as the 862, usually give the nearer-term firm releases.

Why does review frequency matter?

Your plan is only as current as the last forecast you loaded. A longer gap extends the period during which demand can change unseen, so you need more buffer to cover the same service level.

Which service level should I choose?

Pick based on the cost of a stockout versus carrying cost. Many manufacturers use ninety five percent for general items and higher for items with line-down penalties, but use your customer agreement and cost data.

Does the formula work for lumpy demand?

Not well. It assumes demand is roughly normal. For very lumpy or intermittent demand, use a simulation or a bootstrapped method on actual release history instead of the square root formula.

If you want 830 and 862 schedules loaded into planning automatically and compared to actual releases, we can build that with your ERP team.