Computers & Laptops

RAM Capacity Calculator

Total memory from the number of modules and the capacity of each.

6 inputs Free, no sign-up

Your figures

Optional - use this if you have two different sizes fitted.

Try an example

Result

Your result

Enter your figures and the result appears here.

Estimates only. Rates, fees and specifications change. Confirm against the official source before you rely on a figure — see our disclaimer.

About this calculator

Total memory is modules times capacity each, and the only subtlety is the unit. A module sold as "16 GB" is 16 GiB — 17,179,869,184 bytes — because memory is the one place in computing where the decimal prefix is used for a binary quantity by universal convention.

This page counts in binary units and says so, rather than converting quietly.

How to use this calculator

  1. Enter how many modules are fitted and what each one is.
  2. If you have two different sizes, use the second pair of fields for the other set.

Not sure what is fitted? Task Manager's Performance tab on Windows, System Information on macOS or lshw -short -C memory on Linux will say.

The formula

Total = Modules x Capacity of each  (+ a second set if you have one)
SymbolMeaningUnit
Modules How many are fitted
Capacity Capacity of each GiB

Worked example

Two 16 GB modules:

2 x 16 = 32 GB (which is 32 GiB, or 34.36 decimal GB)

Notes and limits

  • This is arithmetic, not a compatibility check. Whether your machine will take these modules depends on the number of slots, the maximum the board and processor support, the speed, the form factor and what is already fitted — none of which is contained in a capacity.
  • Integrated graphics reserve a share of system memory on many machines, so the figure the operating system reports as available is often below the total fitted.
  • Matched pairs matter for performance. Two identical modules usually run in dual channel; a mismatched pair may run part of the range in single channel.
  • Many laptops have some memory soldered to the board and one free slot, which caps what an upgrade can reach.

What this calculation assumes

  • Memory is counted in binary units, as it is always sold and reported.
  • This is arithmetic only and makes no claim about compatibility with any machine.

Frequently asked questions

How do I work out my total RAM?

Multiply the number of modules by the capacity of each. Two 16 GB modules is 32 GB. If you have different sizes fitted, add the sets together.

Is a 16 GB module 16 GB or 16 GiB?

It is 16 GiB - 17,179,869,184 bytes. Memory is the one product sold with decimal prefixes on binary quantities, which is why it is the only place the two conventions do not cause an argument.

Will these modules work in my machine?

This page cannot say. Slot count, the maximum the board and processor support, the memory standard, the speed and the form factor all matter, and none of them is a capacity. Check your machine's manual or its manufacturer's support page.

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