House Extension Cost Tracker

Who this is for

An extension costed stage by stage. Each stage, from design and groundworks to decoration and external works, has a line for what was quoted, what was agreed, what has been paid and any extras. The sheet works out what is left on each stage and how the whole build compares with your budget.

Homeowners building a single or double-storey extension, whether through one main contractor or several trades, who want to see where the money is committed before the invoices arrive.

What this helps you track

• The quoted and agreed figure for every stage of the build
• What has been paid to date on each stage
• Extras agreed along the way, kept apart from the original price
• What is still to pay, stage by stage
• How the committed total compares with your own budget

How to use it

1. Write the address, a short description of the extension, the main contractor, your budget and the start date at the top.
2. Enter the quoted figure for each stage from the quotes, and the agreed figure once the price is settled.
3. Add the supplier for each stage; where one contractor covers several stages, write their name on each.
4. Record payments as they are made and extras only once they are agreed in writing.
5. What is left on each stage and the totals are worked out in the browser and the workbook; on paper, add the agreed and extras and take off what is paid.
6. Check the variance against budget in the summary before agreeing any further extra.

Formats

• Printable PDF (A4 and US Letter)
• Fillable PDF with form fields
• Fill in online, saved in your browser
• Excel / Google Sheets workbook

The printable is laid out inside a box that fits both A4 and US Letter, so the two files are identical and neither one is scaled. The fillable PDF has real form fields. The workbook uses plain formulas only — SUM, IF, COUNTIF and the like — so it opens in Excel, LibreOffice and Google Sheets without anything breaking, and every calculated cell is grey so you can see which figures it worked out.

How to print

Download the A4 or US Letter file to match the paper in your printer, open it in a PDF reader and print at 100% — not "fit to page", which shrinks the writing space. Both files leave a 14 mm margin, which clears the unprintable edge on home printers. To print the online version with your entries in it, use the Print this sheet button, which prints only the sheet and none of the page around it. More on printing.

Questions

What is the difference between quoted and agreed?

Quoted is the figure in the first quote; agreed is the price you settled on after questions, changes or negotiation. Keeping both shows how far the price moved before work began, apart from anything added later.

How is the variance against budget worked out?

Your budget minus the agreed total and the extras. A positive figure means the committed cost is inside the budget; a minus figure means it is over. The budget is whatever figure you enter, not a guide price.

What should count as an extra?

Anything agreed after the price was set: a change of window, extra steelwork, unexpected ground conditions. Record each one in the change and decision log as well, so the reason sits alongside the cost.

Can I add stages that are not listed?

Yes. The stages are a starting set; there are spare rows for anything else, such as a kitchen fit, landscaping or professional fees.