Table of hardness scale equivalences

Section 4.3 explained why one manufacturer’s hardness degrees do not translate into another’s: each scale uses a different durometer, a different force and a different moment in the manufacturing process. This table exists because the player needs it anyway, and because imperfect guidance beats none. What follows is not a conversion: it is a map of approximate correspondences.

Read this first. No row in the table claims that two values are equal. It claims that they occupy a similar position within their own scale. A fixed conversion factor would be false, because the discrepancy between scales changes with the hardness zone and with the type of sponge: two rubbers that line up in the medium band can diverge noticeably in the hard band. The table gives the neighbourhood, not the address.

Approximate correspondences

Band	ESN	DHS	Butterfly	How it feels
Very soft	35-37°	—	28-30°	Absorbs almost everything; control play dominates
Soft	37-42°	35-37°	30-32°	Forgives imprecise contact; little response to a hard stroke
Medium	42-47°	37-39°	32-34°	The most common range in club play
Hard	47-50°	39-41°	34-36°	Demands arm speed to activate
Very hard	50-55°	41-43°	—	The territory of the Chinese competition sponge

The empty cells are not omissions: they indicate that the brand does not normally manufacture in that band. Butterfly works in a narrower range than the others and rarely labels above 36°; DHS does not compete in the softest band.

The three scales, one sentence each

ESN. Based on the Shore standard, it is the most widespread in Europe and the one used by Tibhar, Andro, Donic and much of the continental catalogue. Its values run from 35° to 55°. It is the best-documented scale and the most frequently cited in reviews, which makes it the implicit reference point when somebody mentions “a 47° rubber” without naming a brand.

DHS. A system of its own, with values systematically lower than ESN for a similar perceived hardness. The gap is not constant: in the table it runs from three or four degrees in the soft band to about ten in the very hard band. On top of that, DHS distinguishes between commercial and selected versions —provincial, national— which can carry different hardnesses under the same product name, as section 5.9 develops.

Butterfly. An internal scale, a narrow band and a protocol not published in the detail other manufacturers have offered. The Tenergy range runs between 32 and 36°, values corresponding to noticeably higher hardnesses on the ESN scale. It is the scale about which least can be stated with confidence.

How to use the table without going wrong

Three rules, in order of importance.

1. Always compare within the same scale. Between two rubbers from the same manufacturer, the hardness figure is reliable for deciding which is softer. It is the only use in which the number works as a number.
2. Across manufacturers, think in bands rather than degrees. A player who knows they are comfortable in the medium ESN band looks for the medium DHS band, not a specific value. The “band” column of the table is the one that matters; the figures are there to locate it.
3. Confirm with the rubber mounted. The declared hardness describes the sponge in isolation, not the assembled whole. The same rubber on a stiff blade and on a flexible one produces different sensations, for the reasons section 11.1 explains. No number replaces three sessions of play.

The implications of each band —what a soft sponge is after, what a hard one demands— are developed in section 5.6. The recommendations by age and physical condition that cite these ranges are in chapter 17.