External doors Cost Calculator

How this calculator works

Every figure in this calculator is the one published in the cost table on our external doors guide. Pick the option that matches your job and the calculator returns that published range, adjusted for your region - it does not model anything the guide does not already say.

That is deliberate. A calculator whose rates drift from the page it sits under is worse than no calculator, because two numbers on the same site disagree.

What it cannot know: access, the condition of what is already there, and anything structural. Those are what separate three real quotes from each other.

What actually moves an external door quote

The calculator gives you a fair budget figure, but three fitters pricing the same doorway can still land some way apart. Most of the gap is in things the dropdown can’t see – what’s behind the plaster, how level the threshold is, and whether the old frame comes out with the door.

What the door’s made of. Composite doors have a solid core and hold their colour, which is why they dominate front-door quotes. uPVC is cheaper and fine for a sheltered back or side door. Timber suits period homes and can be made to any shape, but it needs painting and costs more. Aluminium is the priciest of the four, chosen for slim frames and big glazed openings rather than a standard front door. Two quotes can differ purely because one assumed a mid-range composite and the other a hardwood.

A new slab, or a whole new frame. Hanging a new door leaf into a sound existing frame is a short job. Replacing the frame as well – because it’s rotten, out of square, or the wrong size – means pulling it out and making good the reveal, sometimes with a new lintel on top. That’s a different day’s work and a different price, so check whether a quote is for the door only or the full unit.

The threshold and getting in. A like-for-like swap keeps the existing step. Dropping to a low or level threshold for step-free access changes the sill detail and can pull in the floor finish either side, which adds labour. If access matters to you, say so up front – a level threshold designed to Part M is a different fitting to a standard weathered sill.

The lock and the security rating. A door is only as good as how it’s secured. Look for a unit tested to PAS 24 with a decent multipoint lock and an anti-snap cylinder – many insurers ask about it, and it’s the difference between a door that resists a forced entry and one that doesn’t. Side panels and glazed sections push the price up too, both for the glass itself and the extra framing to carry it.

Making good, and the paperwork. Once the door’s in, someone has to make good the plaster, seal the outside, and tidy the reveal – the finish is where cheap jobs show. A replacement external door is also notifiable for building control on thermal performance, so a FENSA or Certass registered fitter handles the certificate for you. If yours isn’t registered you have to notify building control yourself; the FENSA guidance on building regulations spells out what’s covered.