# The delivery schedule: how to stop guessing how much your customer will buy

date: 2026-07-04

> The delivery schedule (830 in X12, DELFOR in EDIFACT) explained without jargon: how a buyer shares its production plan with a supplier — firm weeks and forecast weeks — so nobody runs out of material or drowns in dead inventory. From the 'EDI without mystery' series.


The plant's purchasing manager calls you on a Tuesday: "I need double the packaging by Monday." You have neither the raw material nor the production shift to pull it off. You let him down. Next month, to make sure it never happens again, you overproduce "just in case"… and that inventory sits in your warehouse for six months, tying up space and capital.

That's the double curse of the guessing supplier: either you come up short and lose the customer, or you overshoot and lose money. And here's the frustrating part — your customer **knew** how much they were going to need. It was sitting in their production plan. They just never told you in time, or they told you over WhatsApp, in a photo of a spreadsheet that was already stale when it was taken.

There's a business transaction built to solve exactly this, with a distinctly unglamorous name: the **delivery schedule** (X12 calls it an 830, but the transaction exists in every EDI language — see the table below).

### What is the delivery schedule, in one sentence?

First the basics: **EDI** stands for *Electronic Data Interchange* — business documents that travel from computer to computer, in a standard format, with nobody rekeying anything by hand. The **delivery schedule** (*Planning Schedule* or release plan) is the document a **buyer uses to share its future purchasing plan with a supplier: which product, how much, and when**, week by week.

It's not a purchase order. It's something more valuable: it's your customer telling you *"here's what's coming."*

### Firm vs. forecast: the heart of the document

A typical delivery schedule splits the horizon into two zones:

- **Firm zone**: the next few weeks (2, 3, 4 — whatever the parties agree). These quantities are a commitment: the buyer will order them. You can produce against them with confidence.
- **Forecast zone**: the rest of the horizon (12 weeks, 6 months, whatever makes sense). These are the buyer's best estimates. They change — which is why the schedule is resent every week with refreshed numbers. You don't produce against them, but you do **buy raw material, reserve capacity, and plan shifts**.

That distinction is what breaks the guessing cycle: the firm zone gives you certainty to produce; the forecast gives you time to prepare.

### A concrete example: the food plant and its packaging supplier

Picture a food plant in Valencia, Venezuela, that buys containers and boxes from a domestic supplier. Every Monday, its planning system generates and sends a delivery schedule covering 12 weeks:

1. **Weeks 1 and 2 (firm):** 40,000 containers and 3,500 boxes per week. The supplier schedules them into production immediately.
2. **Weeks 3 through 12 (forecast):** estimated quantities, including a spike in week 9 because a seasonal promotion is coming.
3. The supplier sees that spike **seven weeks ahead**: it buys the resin and cardboard in time, negotiates a better volume price, and books an extra shift.
4. The following Monday, the updated schedule arrives. If the promotion grew, the forecast rises and the supplier adjusts. No panic calls. No "I need double by Monday."

The formal purchase orders (or releases against a blanket contract) come later — but by then, nobody is surprised. They merely confirm what both sides have been watching all along.

{{< figure src="/images/diagrams/plan-entregas-en.svg" alt="The delivery schedule horizon: firm gets produced, forecast gets planned" caption="The delivery schedule horizon: firm gets produced, forecast gets planned" class="diagram" >}}

### What each side gains

| | Without a delivery schedule (guessing) | With a delivery schedule |
|---|---|---|
| **Supplier** | Produces "just in case"; buys raw material last-minute and expensive | Produces against firm demand; buys inputs early at better prices |
| **Buyer** | Line stoppages for lack of material; emergency calls | Reliable supply; the supplier saw it coming |
| **Inventory** | Either dead in the warehouse or missing on the line | Sized to real demand, refreshed weekly |
| **Relationship** | Claims and mistrust | One plan, seen by both |

### Common mistakes (and one myth)

- **"The forecast is a purchase commitment."** No. Only the firm zone is. Confusing the two zones is the number-one source of commercial disputes. What counts as firm and what counts as forecast gets agreed in writing before you start.
- **Sending the schedule once and never updating it.** A two-month-old forecast is worse than none: it creates false confidence. The value lives in the periodic resend, usually weekly.
- **"That's only for giant assembly plants."** This transaction was born in the automotive industry, true — but it applies to any relationship where one party buys from the other on a recurring basis: food plants and their packaging, pharma and its inputs, consumer goods and their raw materials.
- **Receiving the schedule and ignoring it.** Getting the document and still planning off the same old spreadsheet means paying for certainty and continuing to guess.

### The same document in every EDI language

The delivery schedule is the transaction; "830" is just what one standard calls it. Depending on who you connect with, you'll find it under these names:

| Standard | Message | Where you'll see it |
|----------|---------|---------------------|
| [ANSI X12](/en/blog/x12-the-edi-language-of-the-americas/) | 830 (Planning Schedule with Release Capability) | North America and the Americas |
| [UN/EDIFACT](/en/blog/edifact-the-edi-language-of-the-world/) | DELFOR (Delivery Schedule) | Europe, automotive, export |
| [TRADACOMS](/en/blog/tradacoms-the-grandfather-of-retail-edi/) | — no direct equivalent (it was born for retail's order-delivery-invoice cycle) | Legacy UK retail |
| SAP IDoc | DELINS / DELFOR01-02 (SAP's internal format: not a company-to-company standard, but it's what your SAP ERP emits and receives) | Companies running SAP |
| [GS1 XML](/en/blog/gs1-xml-the-language-of-business-learns-web/) | Forecast (Plan family) | Modern GS1 platforms |

The takeaway: **learn the transaction, not the number**. If you understand the delivery schedule — firm, forecast, horizon — switching syntax is a mapping exercise, not a fresh start.

### The natural next step

The delivery schedule tells you *what's coming*. Its sibling, the [advance ship notice](/en/blog/edi-856-the-truck-that-calls-ahead/), tells you *what's on the way*. Together they cover the before and the during of every delivery.

If your big customer has already asked you to "work with EDI" — or you're simply tired of producing blind — you don't need an IT department to start: take a look at our [integration solutions](/en/solutions/) and compare them against your current flow. Guessing was only free on the surface.