Number Series Setup in Business Central : Step by Step Guide (2026)

Every record in Business Central needs a number — every customer, item, sales order, and invoice. Instead of typing these numbers by hand (and risking duplicates), Business Central creates them automatically using number series. Set them up once, and the system numbers everything for you, neatly and in order.

Number series is one of the first things you set up in a new company, and it trips up a lot of beginners. In this guide, we’ll make it simple — you’ll learn what number series are, how to create one step by step, and how to handle the clever bits like relationships and manual numbering. Let’s get started.

What is a Number Series? (in simple words)

Think of a number series like a ticket machine at a counter. Each customer takes the next ticket — 1, 2, 3, 4 — with no repeats and no gaps. A number series does the same thing for your records in Business Central.

When you create a new sales order, the system takes the next number from the sales order series (say SO-001001), and the next order gets SO-001002, and so on. You never have to think about it.

You set up a separate series for each type of record — one for customers, one for items, one for sales invoices, one for purchase orders, and so on. This keeps everything organized and, importantly, keeps your financial documents in proper sequential order for auditing.

Code vs Line – The Two Parts of a Number Series

Every number series has two parts, and understanding the difference makes everything click:

So you first create the code (the container), then add at least one line (the numbers). You can even add several lines to one code, each with a different starting date — handy when you want a fresh number range every year.

Step 1 : Create a No. Series Code

1. Press Alt + Q and search for “No. Series”, then choose the related link
2. You’ll see the list of existing number series. Click New
3. In the Code field, enter a short name like S-INV or CUST
4. In the Description field, write what it’s for (like “Sales Invoices 2026” or “Customers”)
5. Leave the Default Nos. and Manual Nos. checkboxes for now — we’ll cover them below

Step 2 : Add a No. Series Line

The code is just the container. Now add the actual numbers.

1. With your new code selected, click Lines (this opens the No. Series Lines page)
2. Enter a Starting No. — for example SINV-26-00001
3. Enter an Ending No. if you want a capped range — for example SINV-26-99999
4. Optionally set a Starting Date if the series should only become active from a certain date
5. Optionally set a Warning No. so the system warns you when numbers are about to run out
6. Set Increment-by-No. (usually 1, so each record gets the next number)

That’s it — your number series is ready to use. Next we’ll explain the key fields so you know exactly what each one does.

Key Fields Explained

Here’s what the important fields mean, in plain language:

Step 3 – Assign the Number Series to a Document

Creating a series doesn’t do anything until you tell Business Central where to use it. You do this on the relevant setup page. Here’s the sales example (other areas work the same way):

1. Press Alt + Q and search for “Sales & Receivables Setup”
2. Open the Numbering FastTab
3. For each document type (Customer Nos., Quote Nos., Invoice Nos., etc.), pick the number series code you want
4. Save

Now, whenever someone creates that type of record, Business Central fills in the No. field automatically from your series. Other areas have their own setup pages — Purchases & Payables Setup for purchasing, Inventory Setup for items, and so on.

Number Series Relationships (Using Multiple Series)

Sometimes you want more than one series for the same type of record. For example, separate item numbers for finished goods versus raw materials, or a special series for foreign sales orders. That’s what relationships are for.

How to Set Up a Relationship

1. Create your extra number series first (the same way as above)
2. Go to the No. Series page and select your main series (the one already assigned on the setup page)
3. Click Relationships
4. In the Series Code field, enter the code of the extra series you want to link
5. Add a line for each additional series you want to relate

Now, when a user creates that record and clicks the assist button (the little arrow) in the No. field, they can choose between the linked series. The main series stays the default, but the others are available on demand.

Suggest Number Series with Copilot (AI)

Setting up number series for a brand-new company used to mean creating dozens of series by hand. Newer versions of Business Central include a Copilot feature that can do the heavy lifting for you.

The Copilot number series feature helps administrators create and maintain number series for all the entities and documents in Business Central. You give it structured input or even a plain-language instruction, and it suggests a full set of series you can review and accept.

Common Mistakes to Avoid

• ❌ Range too small — a busy company fills a series faster than you’d think. Use a wide range and set a Warning No.
• ❌ Allowing gaps on financial documents — keep “Allow Gaps in Nos.” off for invoices and other audited records.
• ❌ Forgetting to assign the series — creating a series does nothing until you set it on the relevant Numbering FastTab.
• ❌ Overusing relationships — only split series when there’s a real business reason; too many choices cause errors.
• ❌ Wrong Starting Date — the Starting Date decides which line is active. A future date means the line won’t work yet.
• ❌ Leaving Manual Nos. on everywhere — allow manual numbers only where you truly need them (like customers), or you’ll get inconsistent numbering.

FAQ – Number Series in Business Central

What is a number series in Business Central?

It’s a system that automatically assigns unique, sequential numbers to your records — customers, items, sales orders, invoices, and more. You set up a code and a line defining the numbers, then assign it to a document type. Business Central then numbers new records for you automatically.

What’s the difference between the No. Series Code and the No. Series Line?

The Code is the container — the name and main settings of the series. The Line holds the actual numbers: starting number, ending number, increment, and starting date. You create the code first, then add at least one line.

What does “Default Nos.” do?

When Default Nos. is ticked, Business Central automatically fills in the next number for new records of that type. If it’s off, users have to pick or type a number. Most series should have Default Nos. turned on.

What does “Manual Nos.” do?

When Manual Nos. is ticked, users are allowed to type their own number instead of using the automatic one. This is handy for customers and vendors where you might want to enter a specific code. Turn it off to force automatic numbering.

What is “Allow Gaps in Nos.” and when should I use it?

It lets the series skip numbers rather than staying perfectly sequential. It’s fine for non-financial records like sales quotes, customer cards, and warehouse activities, and can improve performance. Avoid it for invoices and other audited financial documents, which should have continuous numbering.

How do I use more than one number series for the same document?

Use relationships. Create the extra series, then open your main series, click Relationships, and add the extra series’ code. Users can then pick between the linked series using the assist button in the No. field.

Can I start a new number range each year?

Yes. Add another No. Series Line to the same code with a new Starting Date (like January 1) and a new Starting No. Business Central automatically switches to the new line once that date arrives, so your numbering can reset or change each year.

Can Business Central set up number series for me automatically?

Yes. Newer versions include a Copilot feature that suggests number series for all entities and documents based on your input or a plain-language request. It’s especially useful when setting up a brand-new company. You review the suggestions before applying them.

What is the maximum length of a number in a series?

The maximum length is 20 characters. That’s enough for a prefix, a year, and a counter — for example, SINV-26-00001 — while keeping numbers readable.

Final Thoughts

Number series look technical at first, but the idea is simple: create a code, add a line with your numbers, and assign it to a document type. Do that once, and Business Central numbers everything for you — neatly, in order, and ready for auditing.

Start with the basics: a clear code, a wide number range, a Warning No., and Default Nos. turned on. Add relationships only when you truly need them, and let Copilot speed things up when setting up a new company. Get this right early, and the rest of your Business Central setup runs much more smoothly.

Stay tuned to NavisionPlanet for more simple, step-by-step Business Central guides drawn from real project experience.