Quick question about RAM

I have a Dell Inspiron 15 that I’m looking to upgrade—currently sitting at 4GB of RAM, and I'd like to bump it up by another 4. I'm trying to figure out how many slots I actually have available and what specific stick I need to buy. Should I grab a single 8GB module, another 4GB one, or just swap both out for two 4GB sticks? It's all a bit fuzzy to me. Since I live in a pretty small town, I don't really have access to any specialized tech shops to ask for help.
Where can I check this info, or how should I go about it?

Anyway, my laptop is a
Dell Inspiron 15

Thanks in advance

Grab yourself a little free utility called CPU-Z. [I think there might be an American English option during the setup process, if I recall correctly]
Once you click on the RAM section, you'll be able to see all the specifics [highlighted by those red arrows here]



You should also download this one as well: http://www.hwinfo.com/download.php
It lets you dig into the finer details—like the exact model, the manufacturer, the voltage, and whether you're looking at DDR3 or something else entirely

Your laptop has two memory slots and tops out at 16GB total (2x 8GB). So, if you're sitting on 4GB right now, you just need to grab another 4GB stick. As for which specific RAM to buy, check what darkowl72 suggested, though it probably isn't any of those options. Honestly, there's no point in buying the part if you aren't planning to install it yourself. First off, you'll void your warranty, and second, these things are built so poorly that you have to basically gut the entire machine just to perform a simple RAM upgrade. It’s idiotic design...