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Renovation Cost Calculator

List each item of the job, such as materials, labour or hire, with its quantity and your price. The calculator adds a contingency for surprises and any tax, giving a subtotal and total you can print, export to CSV or share. The example items add up to 3,840, and a 15% contingency brings the total to 4,416.

Estimate only. Get written quotes before you commit; prices vary by region, season and site conditions.

Measurements

Units
Line items

10–20% is a common allowance for surprises.

Results

Estimated total

$4,416.00

Subtotal
$3,840.00
Contingency
$576.00
Tax
$0.00
Show the working
  1. Subtotal1 × 2500 + 12 × 45 + 1 × 800 = 3840
  2. Contingency3840 × 15% = 576
  3. Total3840 + 576 + 0 = 4416
Paper and orientation
Open the list

How to use the renovation cost calculator

  1. Add one row per line item: a description, the quantity and the unit price.
  2. Use Add another for each extra item and the ✕ button to remove one.
  3. Set the contingency percentage.
  4. Enter any tax rate that isn’t already included in your prices.
  5. Print, download a CSV or copy a share link.

How the total is worked out

Subtotal = Σ (quantity × unit price). Contingency = subtotal × contingency %. Tax = (subtotal + contingency) × tax %. Total = subtotal + contingency + tax. Everything is calculated in your browser, and your list is not uploaded.

Worked examples

Small kitchen refresh. Cabinets 1 × 2,500, floor tiles 12 × 45 and an electrician 1 × 800: subtotal 3,840. With a 15% contingency (576), the total is 4,416.

With tax. The same list with 10% tax on top: (3,840 + 576) × 10% = 441.60, for a total of 4,857.60.

How to interpret the results

The total is a planning budget, not a quote. Use it to compare options, decide what to do yourself and what to hire out, and set aside the contingency rather than spending it on upgrades.

Tips and common mistakes

  • Get at least three written quotes for big items.
  • Include the small things: waste removal, permits, tool hire, delivery and making good.
  • Use the same units for quantity and price, for example m² and price per m².
  • Revisit the budget as quotes arrive and replace estimates with real prices.

Organising your line items

Group items in the order the work will happen: strip-out and waste, structural work, first-fix plumbing and electrics, plastering, second-fix, flooring and finishes, then decorating. Listing the job this way makes it easier to compare contractors’ quotes line by line and to spot what each quote leaves out. Keep labour and materials on separate rows when you can, because they change for different reasons. If a quote covers several items as one price, enter it as a single line with a quantity of 1.

Keeping the budget up to date

Treat the list as a living document. Replace estimates with quoted prices as they arrive, and record variations as new lines so you can see where the money went. Download a CSV copy at each stage to keep a history.

Assumptions and limitations

The calculator does arithmetic on the numbers you enter; it doesn’t know local prices or which permits you need. Check with your local authority before structural, electrical or plumbing work.

Frequently asked questions

How much contingency should I add?

Many renovators allow 10–20% for unforeseen work, with more for older buildings where hidden problems are likely. The calculator starts at 15%, which you can change.

Does the calculator include typical prices?

No. Prices vary widely by region, season and contractor, so you enter your own from quotes or supplier price lists. That keeps the estimate honest.

Is tax applied to the contingency?

Yes. Tax is calculated on the subtotal plus contingency, because if the contingency is spent it is usually taxed too. Leave tax at 0% if your prices already include it.

Can I share my budget?

Yes. The share link stores your items in the link itself, not on a server. Anyone with the link can see the numbers, so share it only with people you trust.

Can I export the list?

Use Download CSV to open the budget in a spreadsheet, or Print for a paper copy.

Sources