What the method fixes
A durometer is a spring-loaded instrument with a specified indenter tip. Pressed against the material under a specified force, it reads how far the tip penetrates on a scale from 0 to 100. High numbers mean little penetration — a hard material.
The method is published, and the scale letter names which indenter and which spring were used. Shore A is the scale for soft and flexible rubbers and covers most gym flooring, massage balls and grip material. Shore D is for rigid material. Shore OO is for gels and very soft foams.
Because the test is defined, a Shore A figure is genuinely comparable between two products measured on the same scale — which puts it in a small minority of the numbers in this catalogue.
What it does not promise
It does not promise resilience. How far a point sinks under load and how quickly the material recovers are separate properties, and a material can be hard and brittle or hard and tough.
It does not promise tear strength, abrasion resistance or how a tile will behave after two winters in a garage.
It does not promise noise performance. Hardness affects it, but thickness, mass, the subfloor and how the tiles join affect it more, and no Shore figure predicts what a neighbour hears.
And it does not translate between scales. A Shore A reading and a Shore D reading on the same sample are two measurements, not one converted into the other, and nothing here converts them.
What it works with
It works with thickness, which on flooring is the dimension that decides what a dropped bar does to the concrete underneath.
It works with mass per tile or per square metre, which is what actually damps a floor.
And it works with the material — recycled rubber crumb, virgin rubber, EVA, TPE — because a hardness figure means one thing in a moulded solid and another in a bonded crumb.
How we read it on this site
Where a maker publishes a durometer figure, the page prints the number with its scale letter and names the source. Where a maker publishes a hardness in words only — firm, extra firm, soft — the page reports the words as words and records that no measured figure was given.
Nothing here converts a description into a number, and nothing compares a Shore A product with a Shore D one as though the scales met.
Questions readers send in about this
Is a higher Shore number better?
It is harder, which is better for some jobs and worse for others. Hard rubber tiles resist a dropped plate and transmit more noise; softer ones absorb more and mark more easily. A page here gives the figure and what it trades, not a ranking.
Why do two figures use different letters?
Because they are different scales for different material ranges. Shore A covers soft and flexible rubbers, Shore D covers hard plastics and rigid rubbers, and Shore OO covers very soft foams and gels. A number without its letter is incomplete, and pages here report both or neither.
Does flooring publish it reliably?
The better tiles do, often alongside a density and a thickness. Budget tiles frequently publish none of the three. Where nothing is published, the page says so and compares on what is — thickness, mass per tile, and how the edges join.
Last reviewed 20 September 2026