How to find out overall health of an SD card? In particular:

  • Part of the question is answered here. For the rest, no, I don't think there is any counter or a way to detect how many times SD card was overwritten. Dec 16, 2015 at 14:58

3 Answers 3


Do I know that one of the SD card can write a few times in the future?

Unfortunately no.

Or do I have to know how my SD card is write so far?

The same, no.

Is there such a register can see this information?

No, IMHO there is not any.

I want to know what the future life of the SD card.

Look for Disk Utility on you dash (as an option press Alt+F2 and type palimpsest)


The limit is not an exact count, and applies to single bits. Generally, the logic on the cards tries to distribute the usage evenly over all bits, so you get a lot more usage out of it than it sounds like. For normal daily usage, the card easily works for five to ten years, so you should not have to worry about that at all.

With very heavy write operations (like defragging a lot), you might be able to reduce lifetime to months, but still the card would not stop working suddenly, it would just slowly lose capacity (as the controller stops using 'burned-out' areas). They also have some spare space that is invisible to the user, and will replace lost areas for a while (until it is used up).

So don't worry, it's more like getting old, not like dropping dead.


There is no simple way knowing the remaining life expectancy for an SD card.

Flash memory in general, including your SD card, is composed of cells of NAND memory. These cells can only be written to, on average, so many times. The actual lifespan of the flash memory as a whole however depends on how well the wear is distributed among the cells. Most cards will use some form of wear leveling to more evenly distribute writes over the free space on the card. Whether or not that strategy is effective depends on the amount of available free space.

Since the SD card may be using wear leveling, either counting total writes or number of writes per sector will not yield reliable information on the total amount of wear. Whereas hard drives usually provide SMART status information on their estimated health, SD cards do not provide such a command or register.

The upside of this story is that flash memory in general fails gracefully: previously written data will not be lost when the device wears out. From that point on, the device will most likely refuse to be written to instead.

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