Kitchen
Appliance Cut-Out Size Calculator
Aperture size for a built-in appliance
Updated 12 July 2026 · Live
What this tool does
Works out the aperture width and height needed to house a built-in appliance, adding a clearance gap to each side.
Enter the appliance width and height and the clearance gap; the calculator returns the aperture size to cut.
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Formula Used
Works out the aperture width and height needed to house a built-in appliance, adding a clearance gap to each side. It runs entirely in your browser and shows the working, so you can check every step against your own figures.
How the appliance cut-out size calculator works
The aperture is the appliance dimension plus twice the clearance — a gap on each side for fitting tolerance and ventilation. The result is the width and height of the hole to cut in the cabinetry. Ovens, fridges and dishwashers each specify their own cut-out, so this is a planning check to confirm the space works before you commit.
What you enter
Enter the appliance width and height and the clearance gap; the calculator returns the aperture size to cut. Every field is editable, and the result recalculates the moment you change a value.
Reading the result
Cut to the appliance manufacturer’s own installation drawing where you have it — this figure sanity-checks that the cabinet opening allows for it. Heat-producing appliances also need a rear or plinth air path the width alone does not show.
Safe by design
This tool plans layout and quantities. It never sizes a gas connection or an electrical circuit — both are regulated trades that a qualified, registered installer must carry out.
Assumptions and limits
This sizes the front aperture from a clearance you enter. It does not set the depth, the rear ventilation gap or the services position — all of which come from the appliance’s installation manual. Always defer to that manual for the final cut.
Using it with the rest of BuildMetricLab
This calculator is one step in planning the job. Pair it with the related tools in this category and across BuildMetricLab to go from a single figure to a full costed plan — a sizing figure feeds a cost estimate, a cost estimate feeds a project budget, and each result carries straight into the next tool. Every BuildMetricLab tool runs entirely in your browser — no sign-up, nothing sent to a server, and the formula is shown on the page so the maths can be audited.
Sources & methodology
Works out the aperture width and height needed to house a built-in appliance, adding a clearance gap to each side. Every result is calculated from the values you enter, all inputs are editable, and no time-sensitive prices or rates are embedded.
Frequently asked questions
How much clearance should I leave?
Around 3–5 mm each side is typical for a snug built-in fit, but always use the figure in the appliance’s installation manual.
Does this include ventilation?
No. Ovens and fridges need a rear or plinth air gap that the front aperture does not capture — check the maker’s cut-out spec.
What about the aperture depth?
This sizes the front opening only. Depth, services and fixing positions come from the appliance manual.
Why add clearance at all?
A little tolerance lets the appliance slide in and out, absorbs slight out-of-square cabinetry, and gives heat somewhere to go.
Spotted something off?
Calculations or display — let us know.