How to Import Spreadsheets and CSV Files

If you already track your income and expenses in a spreadsheet, you don't need to re-enter everything manually. Affordable MTD can import your CSV or Excel file and automatically map your columns to the HMRC categories required for MTD quarterly submissions.

This is designed for the way most sole traders and landlords actually work — keeping a simple spreadsheet and submitting the totals to HMRC each quarter.

Supported file formats

• CSV (.csv) — comma-separated values, the most common export format from any spreadsheet app
• Excel (.xlsx) — Microsoft Excel workbooks

Both Google Sheets and Apple Numbers can export to CSV. In Google Sheets, go to File → Download → Comma Separated Values. In Numbers, go to File → Export To → CSV.

How to import a file

1. Go to the quarter you want to submit and click Submit.
2. Select "Import CSV/Excel" as your data entry method (instead of manual entry).
3. Upload your file — drag and drop it into the upload area, or click to browse your files.
4. Review the column mapping. Affordable MTD reads your column headers and automatically matches them to HMRC categories. You'll see a preview of what was detected.
5. Adjust if needed. If any columns weren't matched correctly, use the dropdown to reassign them. You can also skip columns that aren't relevant (like dates or reference numbers).
6. Confirm and continue. The parsed totals are shown for your review. Continue to the summary and submission step.

How column mapping works

Affordable MTD auto-detects your column headers and matches them to HMRC's income and expense categories. It handles a wide range of common header names:

Your Column Header	Mapped To
Sales, Revenue, Turnover, Income	Turnover
Travel, Mileage, Vehicle Costs	Travel costs
Phone, Internet, Broadband	Admin costs
Repairs, Maintenance	Repairs & renewals
Rent, Property Costs	Premises costs
Accountant, Legal Fees	Professional fees
Advertising, Marketing	Advertising costs
Staff, Wages, Salaries	Staff costs

If your headers use different names, or you have custom columns, you can manually assign them during the mapping step. Any column that doesn't match an HMRC category can be skipped.

Handling disallowable expenses

Some expenses include both allowable and disallowable portions — for example, phone bills that are partly personal use, or meals with a business entertainment element. Affordable MTD supports separate disallowable columns for each expense category.

If your spreadsheet includes a column for disallowable amounts, map it to the corresponding disallowable category during the mapping step. If you don't track disallowable portions separately, you can leave these unmapped and handle them in the manual review.

AI-assisted categorisation

If your spreadsheet has transaction-level data (individual expenses with descriptions rather than category totals), Affordable MTD's AI categorisation can automatically assign each transaction to the correct HMRC expense category based on the description.

For example, a row described as "Train to London for client meeting" would be categorised as travel costs. "Adobe Creative Cloud subscription" would go under admin costs.

You always get a chance to review and adjust the AI's suggestions before submission.

Tips for a smooth import

• Use clear column headers in the first row. "Travel" is better than "Cat 7" or "Column F".
• Keep amounts as numbers. Avoid currency symbols (£) or commas in your values — most spreadsheet apps handle this automatically when exporting to CSV.
• One row of headers, then data. If your spreadsheet has multiple header rows or summary rows at the top, remove them before importing, or the parser may not detect columns correctly.
• Quarterly totals work best. If your spreadsheet tracks monthly or daily transactions, consider adding a totals row for the quarter period — or use the AI categorisation feature for transaction-level data.

Common questions

Can I import from Google Sheets directly?

Not directly — but you can export from Google Sheets to CSV (File → Download → Comma Separated Values) and then import the CSV file. This takes about 10 seconds.

What if my spreadsheet has multiple sheets/tabs?

For Excel files with multiple sheets, Affordable MTD will use the first sheet. If your data is on a different sheet, either move it to the first position or export just that sheet as a separate CSV.

Can I re-import if I made a mistake?

Yes. You can re-upload a corrected file at any point before submitting to HMRC. The new upload replaces the previous import.