Computers & Laptops

RAM Requirement Calculator

Add up the memory your own workloads use, with headroom, from figures you read off your own machine.

19 inputs Free, no sign-up

Your figures

Name the work and enter what it actually uses on your machine. Task Manager on Windows, Activity Monitor on macOS or `free -h` on Linux will tell you.

Spare capacity above your list, for the operating system and for whatever you forgot. A choice, not a rule.

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

This page will not tell you how much memory an application needs, because it does not know. The answer depends on your version, your settings, your data and what else you have open, and a figure printed for "a browser" would be wrong for most readers.

What it will do is add up figures you measured, which is the only honest version of the question. Your own task manager has the numbers.

How to use this calculator

  1. Open the work you actually do — all of it, at once, the way you really work.
  2. Read each one's memory use: Task Manager on Windows, Activity Monitor on macOS, free -h and top on Linux.
  3. Enter each as a row, with how many instances you run.
  4. Set headroom for the operating system and for what you forgot.

The formula

Total = sum of (each workload's memory x how many)
With headroom = Total x (1 + headroom / 100)
SymbolMeaningUnit
Workload What each one uses on your machine GB
How many Instances you run at once
Headroom Spare you want above the list %

Worked example

A browser at 4 GB, an editor at 6 GB and a virtual machine at 8 GB, with 25% headroom:

4 + 6 + 8   = 18 GB
18 x 1.25    = 22.5 GB

Which points at 24 GB or 32 GB of installed memory, depending on what your machine takes.

Notes and limits

  • The operating system needs memory too, and it is not in your list unless you added a row for it.
  • Memory shown as "used" by the disk cache is not memory you are short of. It is spare memory being put to work, and it is handed back the moment something else needs it.
  • More memory helps only while you are running out. If nothing is being swapped to disk, adding memory changes very little - your resource monitor will say which situation you are in.
  • This adds up what you entered. It is not advice about what to buy, and it cannot be: that depends on the machine, what it supports, and how you work.

What this calculation assumes

  • Every figure is one you entered. No application requirements are stored in this page.
  • Everything on the list is assumed to run at the same time.
  • The result is the sum of what you entered, not a recommendation about what to buy.

Frequently asked questions

How much RAM do I need?

Measure the work you actually do and add it up, which is what this page does with your figures. There is no general answer, and any page that gives one without knowing your workload is guessing.

How do I find out how much memory something uses?

Open it and look: Task Manager's Details tab on Windows, Activity Monitor's Memory tab on macOS, or `top` and `free -h` on Linux. Use the figure while you are working rather than just after launch.

Why does my machine show most of its memory in use?

Because unused memory is wasted memory. Operating systems fill the spare with disk cache and release it instantly when a program asks. The figure to watch is swap activity, not the "used" percentage.

Will more RAM make my computer faster?

Only if you are short of it. Going from constant swapping to none is transformative; going from comfortable to very comfortable changes nothing measurable.

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