Milling Formula Interactive Calculator

@Vince.Fab turned me on to this. I’ve not seen it before but perhaps it’s common knowledge to those here.

Just thought I’d post it up for reference, maybe inclusion in the wiki.

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Thanks! it was already listed at: but I’ve added a footnote link back here, 'cause there’s nothing I love more than circular references.

It would be nice to have more commentary on the calculators on the wiki — they all seem to work well enough, but I’m beginning to feel very strongly that what’s needed is a physics-based simulation which includes information on machine rigidity, and which takes into account the specific sort of cut being made. (or just making test cuts using a technique such as: )

I’m currently working on a project which I hope will work something like this:

  • use OpenSCAD to 3D model a design using virtual tooling
  • open the parameters for a design and generate toolpaths in G-Code using TPL ( with the following inputs:
    • design parameters
    • tooling specifications
    • material specifications — this will include allowing one to set chipload and roughing clearance and to take finishing passes
    • toolpath specifications — adaptive, &c.
    • machine specifications

and it will include some sort of graphical program which will list all the feeds and speeds we have and extrapolate from them, allow one to interact with them, showing chipload and material removal rate and so forth, and to write out a desired set of feeds and speeds as a JSON file which will be used.

It kills me that the only exchange formats for feeds and speeds and endmills seem to be:

(if anyone knows of anything which I’ve missed, I’d be glad to know of it)

I wish I could use G-Wizard, but I don’t think that my opensource approach would be fair to the author, so I’ve avoided it.


Yep, I used this one often to calculate SFM and chipload. My only iritation is that there isn’t a metric option so I just ended up making my own spreadsheet.

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Of course, I gotta ask…mind sharing that?


Sure, let me finish up with work and I’ll get to it this weekend. Remind me if I don’t.

Here you go! It’s pretty much the same thing but includes both sets of units.

A link to my Onedrive Excel file:!AthI8oTLE_4Ggr0vYtlHBhglgeEPNw


Did you check your calculator against the other offerings? Are you coming with similar results. Of course I could try it myself but if you already have…

I appreciate that many people have devoted time to preserving and sharing their accumulated knowledge of machining materials.
What I am looking for is a way to specify the material type to be machined, part or slab thickness height from waste board, and some information on the machine (as mentioned: rigidity, as well as torque for spindle and steppers/servos, spindle RPM range, and maybe cutting area). After that a recommendation for end mill, speeds and feeds, etc. would be the result in a human readable format. I’m not recommending this because I’m lazy, I think an app like this would help bring many more people into machining that are otherwise intimidated or struggle with other aspects of machining, but are very capable creative people who just want to make stuff.

It is the same calculator as the first post, just both types of units. Nothing more.

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