Hello everyone! I am planning to triple boot Windows 10, Mac OSX Yosemite, and Arch Linux on my 240gb SSD.

I'm wondering how to set up the partitions so first things first:

1)What is the MINIMUM size a Windows OS partition should be?
I've heard huge sizes and tiny ones. I am not looking for an extreme answer; "you need at least 180GB to run windows!" because that's BS... (If you also know the minimum/required for Linux in general that'd be great; if that's not clear enough use Ubuntu as the example)

I need to know the minimum and recommended *healthy (usable)* size for a Windows Partition because I'm planning to triple boot.

2) If I have 240 GB (225 GiB) and don't want to use beyond 80 space how should I partition it? So that I will have:
i) Windows 10 ii) Mac OSX Yosemite iii) Linux and iv) storage space: Games like Skyrim, maybe a program or two

I know it's up to me but I want some general guidelines. My main problem is figuring out how much space I should set aside for the Windows partition.

Any help would be appreciated. Thanks guys!

For the Windows 10 minimum requirements, why not go to the source, then take whatever MS says and triple it.

Why triple? (that gives me 60, I'm just curious what tripling it implies; someone else suggested I do no less than 80)

Go with MS's recommendation is my advice.
However, looking at the other sysreqs, they do appear 'conservative' (on the RAM anyway) and are what I consider "general guidelines".
IMO, tripling it is a good idea.

60/50/40/what ever you decide on, only experience will teach you what works best.
You can always resize later.

I no longer do dual boot because I found that I never went into the alternate OS. Needless to say I've never configured triple boot.

Why not evenly split this drive into 3 chunks and let each OS show you how good or bad it works given 80 Gig of size each?

I would not put data storage on my primary OS drive, I usually put extended data storage on an added drive which would be > 1 TB.

do you have any other drive (for example storing your home/data/whatever)?

Yes I have a 3TB HDD for the rest/majority of my storage but want to put os's on the SSD.


How easy is it to resize partitions? will it break my set up?

(Because if its easy and safe I cn make big partitions and shrink them later)

Grow, very easy. Shrink, not so easy. I recommend starting small and growing as needed versus the other way around.

And I'm not talking about the actions. The actions are not so difficult either way, but to shrink the utilities need to ensure that existing data is retained and this involves moving and consolidating data. There are some risks such as if the system is doing these actions and power is lost during that time. A recommendation is that the system have a battery back-up. To grow a partition it is just simpler in that the partition size is altered.

Keep in mind that if MS says that you need 16 GB, then that will likely leave you with almost no free space left for other programs.

Linux /root partition can be 25g. Or less, if you are running a leaner linux. Linux /home partition should be as big as the storage space you intend to use. If you aren't going to store big data (photos, videos, etc), then a /home partition could be 10, 20, or 30gb. But as you likely know, storage space gets eaten up pretty quickly by various media files these days. If you are putting linux on an SSD, you should read some of the tutorials available on the net.

Because, if you plan on using the MS side of the computer and start installing applications, you will very quickly exceed the "minimum" requirement. On my Windows 7 C:\ drive, I have move than 148 GB used.

I have mine at 50G, but it's a very tight fit.

Historically MS have always specified the absolute bare minimum for the install (of just the OS & eg Office) and basic running (usually that equates to 'walking').
Probably a marketing trick to ensure that you buy it... once you have, you're likely to keep it and if necessary, up your HW to match.

resizing is easy, but only if you have enough space for that. In your case (3 OSs on the same drive) probably you will not be so simple.
240 GB SSD is more than enough for the 3 OSs if you can use your additional drive for your data, home dir and common files.
Partitioning also depends on the softwares you want to use, for example if you want to install a lot of MS tools you will need more space.
In general I would use 100 GB for MS and 70/70 for the others. You can also try to keep some free space to be able to modify/resize partitions later.

I shouldn't leave any space unpartitioned right? I can leave free space but it should still be in a partition correct?