How accurate is the estimate?

It is a band, not a price, and its accuracy depends entirely on how well the work type matches your project and how much you know about the building's condition. On an unopened old property, treat the top of the range as the more likely figure.

Why does access change the number so much?

Because on this island it changes almost every line rather than adding one, and it applies twice — material in, waste out. A stepped-lane property in Oia and a plot with a road outside are genuinely different projects.

Does it include VAT and fees?

No, deliberately. They are listed as exclusions in the output rather than folded in, because folding them in makes the construction figure incomparable with a contractor quotation.

Can I use this to check a quote I have received?

That is one of the better uses of it. If a quotation is far outside the range, ask what it includes or excludes — the difference is usually in the exclusions rather than the rates.

Why are the figures blank?

The cost index has not been published yet, and this tool reads directly from it. We will not put invented numbers into a tool that people would use to set a budget.

Santorini Renovation Cost Estimator

The estimator is built and functioning, and it has no figures to work with yet. It reads directly from assets/data/cost-index.json, which ships with empty values because we will not publish invented cost data. Choose the options below and the tool will show you exactly which bands and multipliers it would apply — with the numbers blank until the index is published.

Why the cost index ships empty

Property type and work

Floor area

Square metres of the area being worked on, not the whole plot.

Scope tier

BasicSound and functional, standard finishes MidGood specification throughout HighPremium finishes, made-to-measure elements

Access to the property

Where does a lorry actually stop? On this island this is frequently the largest single adjustment.

Indicative range — awaiting published cost data

This is not a quotation. It is a budgeting aid built on published bands. A real price requires someone walking the property and opening parts of it up, because on an existing building the cost is decided by what is behind the plaster. See how this is priced.

What the estimator does, step by step

No hidden model. It performs exactly the five steps set out in the cost index, and it shows you each one:

Takes the base €/m² band for the work type you selected.
Multiplies by the floor area you entered.
Applies the scope tier factor.
Applies the access multiplier for your property.
States what it has not included — professional fees, permit fees, VAT and contingency — rather than folding them in silently.

You can do the same arithmetic yourself from the cost index. That is deliberate: a tool whose workings you cannot check is a tool you should not trust.

What it deliberately does not model

Being explicit about the limits is more useful than a wider range.

Condition. The single biggest variable on an existing building, and it is invisible until something is opened up. Two identical houses can differ by a multiple.
Ground. Depth to competent material varies across a single plot. Only a trial pit answers it. See foundations in volcanic ground.
Approvals. Permit, legalisation and archaeological costs are separate and can be substantial. See the permit timeline.
Long-lead and imported items. A specific finish with a long lead time is a programme cost as well as a material one.
Your decisions. Finish selection alone can move a project by more than every other factor here combined.

No JavaScript The estimator needs JavaScript to calculate. The underlying bands, multipliers and method are all published in full on the cost index, and the five steps above are the entire calculation — you can do it with a calculator and get the same answer.

Renovation cost estimator

What the estimator does, step by step

What it deliberately does not model

Tell us what needs doing