Interior quality is one of the most important — and most subjective — factors when evaluating a space. Whether it’s a home, hotel, office, or Airbnb, people often say, “It looks nice” or “The finishes are decent.” But what does that really mean?

Those kinds of impressions are vague. Unstructured. Impossible to compare.

That’s why Interior Quality needs a scale — not to strip away opinion, but to structure it. At Index to Scale, we break it down and score it with purpose.

The Problem with Leaving It to Taste

People throw around terms like “modern,” “luxurious,” or “high-end” — but those aren’t standards, they’re labels. And they mean different things to different people.

One person’s “sleek and minimal” is another’s “cold and clinical.” One renter’s “new kitchen” might just mean white cabinets and a cheap laminate countertop.

Without a scale, “nice” just doesn’t cut it.

So What Do We Measure?

Our Interior Quality Index looks at measurable, observable, and relatively consistent elements that affect how a space feels and functions.

Here’s what feeds into the score:

• Material Quality:
  Real wood vs. laminate. Stone vs. plastic.
  Finishes that last vs. ones that peel.
• Fit & Finish:
  Are edges clean? Are transitions seamless?
  Is the paint job crisp or sloppy?
• Design Coherence:
  Does the interior have a clear, intentional design language — or is it a mashup of random styles?
• Functionality:
  Thoughtful layout, good storage, comfortable lighting — or just aesthetic over substance?
• Aging/Condition:
  Even high-end interiors degrade. We account for visible wear and how well the materials hold up over time.

Each of these components is judged on its own, then rolled into a comparative score — not just on paper, but against other properties in the same category, city, or price range.

Why This Score Matters

You can’t evaluate a property by square footage alone. A 100 m² apartment with premium interiors will feel more livable — and retain more value — than a 130 m² place with hollow-core doors and brittle vinyl flooring.

But traditional listings bury that distinction. Our Index surfaces it.

So instead of this:

“Nice place with modern finishings, 4.7 stars”

You get this:

Interior Quality: 72/99 — Upper tier for this price range, but held back by some aging finishes.

Why It’s Comparative, Not Absolute

A $500K apartment in Lisbon isn’t going to have the same interior quality as a $3M penthouse in New York — and that’s fine.

We don’t expect it to. The score isn’t about hitting a “perfect” number — it’s about where that place stands compared to everything else like it.

Interior Quality is relative. Our index reflects that.

Bringing Objectivity to Subjective Things

This isn’t about pretending style is science — it’s about giving subjective experiences a shared language.

Interior Quality should be:

• Understandable
• Comparable
• Transparent

And that’s what Index to Scale delivers.