Custom Invoice Number set up per Order

You can customize the starting invoice number in GST Pro to control how invoice numbers are generated. This is useful when:

• Resetting invoice numbering from a specific point

• Assigning a specific invoice number to a specific order

The app always counts forward from the first order in April. Whatever number you enter in the "First invoice number" setting is assigned to that first April order, and every order after it gets the next number in sequence.

So if you want invoice #1 to start at a later order — say, the first order in May — you need to work backwards.

Step 1 — Find the gap

Note the order numbers for:

• First order in April → e.g. #1051

• First order in May → e.g. #1058

Gap = 1058 − 1051 = 7

Step 2 — Calculate the starting number

Starting number = 1 − gap = 1 − 7 = −6

Enter −6 in the First Invoice Number field.

Why this works:

The app starts at −6 for order #1051, then counts up:

• #1051 → −6

• #1052 → −5

• ...

• #1057 → 0

• #1058 → 1 ✓

Tips

• Always double-check your calculation before saving

• Test with a sample order to confirm the numbering

• Useful when aligning with accounting requirements