True SD Card Capacity & Speed

Alan Robinson

About this app

This "short" endurance test confirms if your SD card is valid and reliable OR if it's a counterfeit that has way less storage space than advertised. It fills your card with carefully designed files that the app can then verify to ensure that what's written to your flash card can be read back reliability. It also measures read & write speed at the same time, because, why not?

It's not the most pretty app because the focus has been instead on real-world testing and good algorithms. It is, however, easy enough to use. The only way to know your card is good is to fill it to the advertised capacity. Typically this takes less than an hour but can be longer if the card is particularly slow or enormous. Piece of mind is worth the wait and there are no shortcuts to it!

You can also test your phone's internal storage. With USB-OTG you probably can test thumb drives too, depending on how your phone works.

Note: English only. The default settings are reasonable, however, so you may just proceed to "start test".

Ratings and reviews

Testing 5 (cheap)micro SD, with smartphone. they all used to work, but got corrupted, and aren't being detected. (I clean micro sd with rubbing alcohol test and format) tablets,laptops,phones. This app is useful, because I tested a good micro SD, and showed some files corrupted. Deep scan ( wish is useful) for undetected msd, but emulates the internal storage,( not MSD). Formatting is supposed to repair SD, but that doesn't work. Thanks for support.

it's very easy to use. however, because it's a technical app there's really no, for example, press here button. read it and it kind of goes one I do this, I do this. I do this. and then you're down to the bottom and you realize there's a button that says begin or I don't remember. literally there's really only one beginning screen. so just press a button and it'll start running as long as your card is plugged in to your phone. maybe with a SD to USBC /usb mini adapter

I am so glad I ran this test! I bought a cheap SD card from Amazon. I didn't know any better. It was a total accident that I found out about fake SD cards. I was just comparing brands to figure out which one to buy & came across the info. (Thanks, Google!) I went ahead and got one just to find out for myself. Phone read it as a 1 TB card. The test found that nearly 75% of the written files became corrupted. This app saved me from likely losing countless priceless memories!!

What’s new

Full android 16 support.