The short answer
NRR is the US rating and SNR is the European one. They use different test methods, so the numbers do not convert or compare directly, and neither tells you whether an earplug is comfortable enough to stay in all night on a pillow.
Shop for earplugs and you will meet three numbers that look comparable and are not.
One brand publishes an NRR. Another publishes an SNR. A third publishes a figure with no standard attached at all. They are printed the same way, in the same font, next to the same kind of product, and a buyer reasonably assumes bigger is better.
What the numbers actually are
NRR: Noise Reduction Rating
The US standard, measured in a laboratory under conditions that do not resemble sleeping. It is a legal labelling requirement for hearing protection sold in the United States.
SNR: Single Number Rating
The European equivalent. Different test method, different maths, and typically produces a higher number than NRR for the same product. So a European brand and an American one describing identical performance will print different figures.
A number with no standard named
This is the one to be careful with. If a listing prints a decibel figure and does not say what it was tested to or by whom, the number is decoration.
Why the comparison does not work
Because the two standards measure different things and are not convertible by any simple arithmetic. There are rules of thumb for approximating between them and they are approximations, not translations.
Which means when you put an NRR next to an SNR, you are not looking at a stronger product and a weaker one. You are looking at two products measured on different scales.
Why it matters more for sleep than for a building site
Hearing protection ratings exist to answer a safety question: will this stop industrial noise damaging your hearing over an eight-hour shift.
That is not the question you are asking. You want to know whether your partner's snoring stops waking you at three in the morning, and no rating on any scale answers that. Snoring is low-frequency and irregular. Ratings are averaged across frequencies in a steady-state test.
A high number tells you a plug performs well in a lab. It does not tell you it will be comfortable on a pillow for eight hours
Comfort is what determines whether it is still in your ear at 4am.
What we publish, and what we do not
We have not put a figure on our pages, because ours have not been independently tested.
When they are, the number and the standard it was tested to will go on the site, and it will be the real one whether or not it is impressive.
Until then, what we will say is what the product does: it softens the room rather than silencing it, it is shaped to stay comfortable on a pillow, and you get thirty nights to find out whether that is true for you.
If you are still deciding what to buy, the more useful comparison is between the materials rather than between the numbers.
If the answer turns out to be no, they go back used and we refund you. That is easier to say than a number we have not earned.
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