SAP SD ATP Availability Check Calculator
The availability check decides how much of a sales order is confirmed and when. Consultants often have to explain why a schedule line shows less than the request. This calculator makes the arithmetic visible in a single bucket.
Your numbers
Purchase orders, production orders, stock transfers.
Confirmed sales orders, reservations, dependent requirements.
Your results
Single-bucket model. A real check works date by date through the requirements and receipts timeline, and may use replenishment lead time and a different checking group.
Confirmed and backorder vs requested quantity
Sweeps Requested quantity from 0 to 1500, holding your other inputs fixed.
Order confirmation explainer
Want an assistant that explains each confirmed quantity from your own data?
Optional. The tool and every export work without this. No spam.
How to use it
Enter the stock, planned receipts, safety stock and the quantity already committed to other demand. Tell the tool whether the checking rule counts receipts and whether it protects safety stock. Then enter the requested quantity. The result shows the ATP quantity, the confirmed quantity, the backorder and the delay if the shortfall must wait for replenishment.
The formula
ATP quantity equals stock plus planned receipts minus safety stock minus committed requirements, never below zero. The confirmed quantity is the smaller of the request and the ATP. Whatever is left becomes the backorder. In SAP these switches map to the checking group and checking rule, which decide which stock types, receipts and requirement types are included.
- Checking group controls the per-material rule
- Checking rule controls the per-application rule
- Scope of check lists which elements count
Worked example
With 800 in stock, 400 incoming, 100 safety stock and 550 committed, ATP is 550. A request for 300 is fully confirmed and 250 remains. A request for 900 confirms 550 and backorders 350, which is delivered after the replenishment lead time. Turning off the receipts drops ATP to 150 and shows how sensitive the promise is to supply that has not arrived yet.
Common mistakes
Frequent problems include counting planned orders that are not firm, forgetting that the check is date-based, and leaving old reservations in place so that ATP looks lower than reality. Also check the strategy group and the requirements class when the confirmed quantity never appears.
Frequently Asked Questions
What is the difference between ATP and stock?
Stock is what is physically there. ATP is what can still be promised after existing commitments and protection rules are applied, and it can include future receipts.
Why would receipts be excluded?
Some companies only promise from stock to avoid broken promises when supplier deliveries slip. Others count firm purchase orders but not planned orders.
Does it model several dates?
No. It is a single-bucket model. For timeline behavior, use the stock requirements list and the multilevel ATP display in the system.
What is a backorder here?
It is the part of the request that cannot be confirmed now and would be rescheduled to the replenishment date.
If you want your planners to see why any sales order line was or was not confirmed, we can build an explanation assistant over your availability data.
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