Kitchen Renovation Cost Calculator

A kitchen is usually the most expensive room in a house to rebuild, because it combines cabinetry, appliances, plumbing, electrics and finishes in one confined space, each with its own trade and its own lead time.

This calculator prices four of those. Cabinetry is linear metres multiplied by a cost per metre. Appliances are a single figure. Labour is installation days multiplied by a daily rate. A contingency percentage is then applied across the whole subtotal.

At the defaults that gives 12,000 of units, 4,000 of appliances and 2,800 of labour, a subtotal of 18,800, and 2,820 of contingency at 15%, for a total of 21,620. Those three components are 63.8%, 21.3% and 14.9% of the subtotal respectively.

The shape matters more than any single figure. Cabinetry dominates, and it dominates through two inputs that multiply together, so an error in either the length or the rate moves the total by the same proportion. At the defaults a 10% change to metres or to cost per metre moves the total 6.4%, against 2.1% for appliances and 1.5% for labour days or rate.

Contingency is the second-largest lever precisely because it applies to everything. Raising it from 15% to 25% adds 8.7% to the total, more than a 10% rise in any single cost category. It is also applied uniformly, including to the appliance budget, which is usually a known price rather than an estimate; where that is the case the contingency is doing more work than it needs to.

How to use it

Enter the running length of units, a cost per linear metre, an appliance budget, the number of installation days, a daily rate for trades, and a contingency percentage. The tool multiplies, sums and uplifts.

Two of those inputs carry more than they appear to. Cost per metre has to cover whatever the supplier quote actually includes, which varies: carcasses, doors, drawers, worktops, handles and plinths are commonly bundled, while sinks, taps and splashbacks frequently are not. And the daily rate has to represent a blend across every trade on site, since a kitchen fit involves joinery, plumbing, electrical work and often tiling and decoration at different rates.

What the result means

The total is the sum of the three priced categories with contingency applied. The breakdown separates units and worktops, appliances, labour and the contingency amount, so the balance between them is visible.

Four categories the model does not contain are worth listing, because on a real project they are not small. Flooring and finishes. Plumbing and electrical alterations beyond the fitting itself, including moving services. Removal and disposal of the old kitchen. Decoration afterwards. Where these apply, they belong folded into the per-metre figure or the daily rate rather than left out, and the contingency is not a substitute for them.

Structural change is a separate question again. Removing a wall or opening a kitchen into an adjacent room brings a different set of trades, structural calculations and, in most jurisdictions, a permit or building control process. None of that is modelled here.

Quick example

With 8 linear metres of units at 1,500 a metre, a 4,000 appliance budget, 10 installation days at 280 a day and 15% contingency, the result is 21,620.00. The breakdown shows 12,000 of units and worktops, 4,000 of appliances, 2,800 of labour and 2,820 of contingency.

Dividing the total by the eight metres gives 2,702.50 a metre, which is a different number from the 1,500 entered as the cost per metre. Both are per-metre figures and they measure different things: the input covers cabinetry alone, the derived figure covers the whole project. Comparing a quote against a published range means checking which of the two the range refers to before drawing any conclusion.

Which inputs matter most

The comparison this calculator supports is between scenarios rather than against a benchmark. Running it twice, once with a supplier's quoted per-metre rate and once with a rate that includes the items that quote excludes, shows how much of the gap between two estimates is specification rather than price.

Because rates for cabinetry, appliances and trades vary enormously by country and by market, no published band travels reliably. What does travel is the structure of the estimate. The International Cost Management Standard exists to give construction and renovation costs a consistent classification across markets, so that what is inside a figure is comparable even when the figure itself is not, and the United Nations Central Product Classification performs the same role for construction services in national statistics.

What is happening under the hood

Linear metres multiplied by cost per metre gives cabinetry. Installation days multiplied by the daily rate gives labour. Those two plus the appliance budget form the subtotal, and the contingency percentage is applied to that subtotal to give the total.

Where this calculation fits a purchase decision

The calculation is quick; the project it informs usually is not. Separating the money side makes it easier to weigh cost against the factors a single figure cannot carry, from how long the kitchen will be out of use to what the household actually wants from the space.

This is a budgeting model rather than a quote. It produces a figure to test supplier and trade estimates against, and to see which line is driving a number that looks too high, rather than a price anyone will honour.