# Split Transaction Rules for Recurring Mixed Payments

- Author: AutoBankConvert (https://www.autobankconvert.com)
- Published: 2024-12-30
- Updated: 2024-12-30
- Category: Statement automation
- Canonical: https://www.autobankconvert.com/blog/split-transaction-rules

> Write split transaction rules for payments that always cover two accounts, such as a mixed supplies and personal card charge, so automation splits them alike.
Split transaction rules divide one bank line across two or more accounts the same way each time it appears. Write one for a recurring payment with a steady mix, such as a phone bill that is part business and part personal. Choose a fixed amount or a percentage, name a remainder account, and check that the parts add up.

## Which payments deserve split transaction rules?

A payment deserves a split transaction rule when three things hold: it recurs, it covers the same accounts each time, and the division between them is stable or follows a known formula. Without all three, a rule only automates a guess, and a person deciding each month will do better.

Good candidates tend to look like these:

- **A shared phone or internet bill** where the client agreed a business share with their tax preparer.
- **A loan payment** of principal and interest, where the lender's schedule gives the interest portion.
- **A combined insurance premium** covering a vehicle and a building, billed as one charge.
- **A rent payment** that includes a fixed parking or storage fee booked to a different account.

Poor candidates are payments where the mix changes from month to month, such as a warehouse store run that might be all supplies one month and half groceries the next. Those belong in review, not in a rule.

Spotting the candidates is easier once recurring payments are grouped. The guide to [recurring transaction detection on client statements](/blog/recurring-transaction-detection) covers how to find lines that repeat on a steady cycle.

## Percentage or fixed amount in split transaction rules

Split transaction rules come in two shapes. A fixed-amount split sends a set figure to one account and the rest to another, which suits a charge with a constant component such as a parking fee. A percentage split divides the whole charge by ratio, which suits a bill where the business share was agreed as a proportion.

Each shape has a weakness to plan for:

- **Fixed amount** breaks when the total falls below the fixed part. A rule that sends 75.00 to Parking from a charge of 60.00 produces a negative remainder.
- **Percentage** produces cents that do not divide evenly. Seventy percent of 83.45 is 58.415, which has to round one way or the other.

Always name a remainder account. The remainder is whatever is left after the fixed parts or the rounded percentages, and putting it in one named place means the split always totals the bank line exactly. A rule that rounds each part on its own can leave the split a cent short of the line, and a cent short is still a reconciliation difference.

## A split transaction rule for a mixed card charge, worked through

Here is a split transaction rule written for one fictional client: a monthly phone and internet bill charged to the business card. The client and their preparer agreed that 70 percent is business use. Every figure below is an example.

**Rule**

- Match: description contains "METRO WIRELESS".
- Condition: debit.
- Part 1: 70 percent to Telephone and Internet, rounded to the cent.
- Remainder: to Owner Draws.

**Applying it to three months**

| Month | Bank line | Telephone and Internet (70%) | Owner Draws (remainder) | Check |
| --- | --- | --- | --- | --- |
| April | 118.40 | 82.88 | 35.52 | 118.40 |
| May | 118.40 | 82.88 | 35.52 | 118.40 |
| June | 131.05 | 91.74 | 39.31 | 131.05 |

June shows the rounding at work. Seventy percent of 131.05 is 91.735, which rounds to 91.74. The remainder takes 39.31, so the two parts total the bank line to the cent.

Notice what the rule matches on. "METRO WIRELESS" is the stable part of the description, while the bank may add an account number or date after it. The post on [bank statement data extraction](/blog/bank-statement-data-extraction) explains how the description field is read, which is the text any rule depends on.

Check which split shapes your tool supports before relying on one. AutoBankConvert's homepage describes rules you write once, plus each client's past coding, assigning each transaction to an account, with uncertain lines going to a review queue; it does not describe split rules. Where a tool assigns one account per line, post the split in the accounting system after import, using the same percentage each month.

## What happens when the split payment amount changes?

When the split payment amount changes, a percentage rule adjusts on its own and a fixed-amount rule does not. A price rise on a phone bill flows through a 70 percent split without edits. A fixed parking fee that goes up leaves the old figure in the rule until someone changes it, so the extra lands in the remainder unnoticed.

Two habits keep this in check:

1. **Add an amount range to fixed-amount rules.** If the charge has always been between 1,200.00 and 1,300.00, send anything outside that range to review. A big jump is a question for the client, not a split to apply blindly.
2. **Date the rule.** Note when the split was agreed and on what basis. When a client moves offices or changes plans, the note tells you the rule needs a fresh look.

Loan payments are the case where the split changes by design. The interest portion falls each month on an amortizing loan, so neither a fixed amount nor a percentage is right for long. Use the lender's schedule or statement each month instead of a static rule.

## When a split transaction rule hides an owner draw problem

A split transaction rule hides an owner draw problem when it turns a habit of mixing personal and business spending into something that looks routine. Splitting a home internet bill is reasonable. Splitting a grocery run every week because the owner uses the business card for the household makes the books look tidy while the habit grows.

Signs the split has stopped being bookkeeping and become a workaround:

- The personal share keeps growing, or covers new vendors each month.
- You write a fresh split rule for a vendor every few weeks.
- The client cannot say what basis the percentage rests on.

In those cases, the better fix is a conversation: a separate card for personal spending, or a habit of paying personal bills from a personal account. Keep a short record in the client's file of each split rule, the agreed basis and the date, alongside their statements; the guide to a [client folder structure for bookkeepers](/blog/client-folder-structure-for-bookkeepers) suggests where notes like that live. If you are thinking of building split logic yourself in a workflow tool, [no-code automation for bookkeepers](/blog/no-code-automation-for-bookkeepers) compares what general tools handle well. For the conversion and categorization that come before any split, [AutoBankConvert](/) shows a batch end to end.