Can I add more RAM to a laptop with soldered memory?

Check in this order:

1. Find the maintenance or hardware guide for the exact model number on the maker's support site.
2. The spec sheet usually says "soldered" or "soldered plus one slot" and lists the maximum memory.
3. For slot models, note the module type (DDR4 or DDR5 SODIMM) and speed.
4. Only then open it, powered off and unplugged, following the manual's order for disconnecting the internal battery.

Our upgrade thread has the general version.

Just solder extra chips on with hot air, it is easy. I have reballed a graphics chip before, memory is the same thing. Order the chips online and match the part number, then the laptop will detect the extra RAM.

Software check before the screwdriver: on Linux, sudo dmidecode -t memory lists the slots and what is in each one. On Windows, Task Manager, Performance, Memory shows "Slots used", for example 1 of 2. If it says 2 of 2 with no empty slot, you are not adding anything.

From the buyer side, I would rather pay for the unit with a free slot, even if it is a little slower, because we can upgrade the fleet when needs change. Please put the exact memory configuration in the listing, soldered amount and slot count.

@Dmitri that is going into my triage notes. The Task Manager slots line is perfect for customers on the phone, since they can read it out without opening anything. I will add the dmidecode line for Linux users.

Please say clearly in the listing when memory is soldered. I once bought a laptop assuming I could add memory later, and found out afterwards that I could not. A single line in the description would have saved me the disappointment.

If a laptop has 8 GB soldered and I add a 16 GB module, does the whole thing work? I read somewhere that part of the memory runs in dual channel and the rest in single channel. Is that right?

@Luis C. on many platforms it works, and the matched part runs as dual channel with the rest as single, but it depends on the platform and on the maker's own limits. Read the maintenance manual for the exact model and never assume. A mismatched pair can also lower the speed of both.

@Tyler B. memory chips are not like a GPU you can lift and reseat. The memory controller and the firmware have to know the new size, the board has to have pads for more chips, and the part has to be the right type. I would not call it easy, and I would not recommend it as a way to upgrade a customer's machine.