Three Line Accounting under MTD for Income Tax
A Practical Guide for Businesses with Income Below £90,000
Making Tax Digital for Income Tax (MTD IT) represents one of the most significant changes to personal tax reporting in recent years.
For sole traders and landlords with income below £90,000, understanding how record-keeping methods fit within MTD is essential.
One method that will be particularly relevant for smaller businesses is Three Line Accounting.
What Is Three Line Accounting?
Three Line Accounting is a simplified reporting method that allows businesses to submit totals using just three income categories and three expense categories.
Income
Turnover (total business income)
Other business income (if applicable)
Expenses
Cost of goods bought for resale (if applicable)
Other allowable business expenses
Disallowable expenses (if relevant)
Rather than categorising every transaction into detailed expense headings such as travel, stationery, subscriptions, or software, businesses submit summarised totals.
This reduces the administrative burden while still meeting HMRC’s reporting requirements.
HMRC says:
The government will also continue to support the use of 3-line accounts within MTD, for customers with annual turnover from self-employment or property income that is below the VAT registration threshold. For most customers, this will avoid the need to categorise expenses when completing quarterly updates, saving them time by allowing them to submit these as a single figure.
Who Can Use Three Line Accounting?
Three Line Accounting is generally suitable for:
Sole traders
Individual landlords
Those with relatively low transaction volumes
For individuals with income below £90,000, this simplified approach is often sufficient
However, Individuals must still ensure they meet the eligibility criteria under MTD IT and use compatible digital software.
How Does It Work Under MTD IT?
Under Making Tax Digital for Income Tax:
Qualifying income sources must keep digital records
Quarterly updates must be submitted to HMRC
A final declaration must be completed at year end
Three Line Accounting does not remove the digital record-keeping requirement — it simply reduces the level of detail reported to HMRC. Instead of submitting detailed expense categories, only three summarised lines of expenses (and income totals) are reported.
You must still:
Maintain digital records of income and expenses
Use MTD-compatible software
Submit quarterly totals digitally
The simplification applies to how figures are summarised and reported — not how records are maintained.