Your Engineering Pad In Browser

It was always easy to spot engineering students in college. They had slide rules on their belts (later, calculators) and wrote everything on engineering pads. These were usually a light brown or green and had a light grid on one side, ready to let you sketch a diagram or a math function. These days, you tend to sketch math functions on the computer and there are plenty of people willing to take your money for the software. But if you fire up your browser, head over to and you might save a little cash.

Although it looks a lot like a Jupyter notebook, the math cells in EngineeringPaper keeps track of units for you and allows you to query results easily. Want to read more? Luckily, there is an EngineeringPaper worksheet that explains how to use it. If you prefer your explanations in video form, check out their channel, including the video that appears below.

If you don’t have the patience for reading documentation, you can jump right into a sheet to compute the parameters of a parallel plate capacitor. If you click the little hamburger above the cell that says “Air” you can select from a few dozen dielectric materials.

By default, the program replies to queries in SI units even if you didn’t use them in the original data. You can, though, force the answers to be in your favorite units if you like. Well, within reason. It stubbornly refused to answer us in furlongs per fortnight. It did, however, accept rods per picosecond.

While we still miss the ubiquitous engineering pad, we have to admit the graphs this thing creates look better than ours. Not to mention the inclusion of a system solver which our old paper pad lacked.

Wolfram Alpha is mostly free and very capable, but they do want you to pay for certain things. If you don’t mind writing Python or some other “real language” there’s always Jupyter.

Thanks to [Daniel Crowley] for the tip!

15 thoughts on “Your Engineering Pad In Browser

  1. Nice idea, but what a dreadful user interface.
    Press “insert cell” and the dialogue box times out after five seconds or so.
    Seems to dislike the system keyboard on mobile browsers too.

    What a shame, a terrible implementation spoiler another good idea.

    1. Yes, good points. Dreadful, maybe, but the competition sets a low bar (in my opinion, others may disagree). It’s easiest to use on desktop browsers. Math editing on mobile is tricky, there’s not really a good way to get the mobile keyboard to show the relevant keys needed to enter math expressions in a convenient way so I opted to create a custom keyboard (Desmos does something similar). It’s open source, so it’s possible for the community to build a better UI on top of the existing calculation and unit tracking engine.

      1. MessagEase, besides being a great input method (especially for those of us with larger hands/fingers), has easy access to a wide variety of special symbols.

      2. I think it has potenetial, I like the simple interface you have made. So I would love to test it more.
        But unfortunately I found it incompatible with ISO keyboards. So I have made a github issue for you. Hopefully it’s a easy fix.

    2. “mobile browser” is a poor gimmick of a browser. If you want to do serious anything, get a laptop. As bonus it comes with a keyboard, and you can really install real software on it.

    3. I tried to use it, and got nowhere. I’m curious though, so I’ll go back later and try it when I can spend some time with it. It does look like the U/I has a few quirks with it.

  2. Looks pretty cool. I can honestly tolerate the web browser interface but I don’t like web hosted tools. I want to host it on my own machine, locally preferably.
    I use jupyter notebook to do calculations and document my work, its also pretty handy and I think it would really benefit from such a mathematical text input tool

    1. It’s a progressive web app, which gives it the ability to work fully offline after the first time the page is opened. Can also be installed natively using Chrome or Edge on Linux, Windows, or Mac, using Safari on iOS, or using Chrome on Android.

  3. Engineering pads…there’s a memory. Those things weren’t cheap, but my gf (now wife of 45 years) had a summer job at National Blank Book, where they were made. I got my year’s supply at a healthy discount.

    Thanks for presenting some modern options

  4. i know i’m closed-minded in general but the archival problem just seems almost insurmountable for something like this. for all its limitations, that’s why i still use plain text for so much. drawing circuit schematics in ascii art is awful but at least i know i’ll be able to read it. this tool will change so much over the next few years that when you come back to an old pad you’re almost guaranteed to be unable to read it. the only way to archive it would be to put it in a pdf. shrug

    fwiw its file format looks like a json version of the xml that typifies spreadsheet output these days. by which i mean, it has a ton of meta data. so yeah you can read it with a text editor if you have to but you’ll be struggling to do so, and you absolutely will not get useful changelogs by checking your sheets into git.

    which reminds me, does anyone know a way to get spreadsheets output as xml without all the garbage? i’d sure love to get useful changelogs out of saved gnumeric sheets :) there’s a part of me that wants to make a spreadsheet program that is just a script run from nvi, that recognizes some sort of inline marker in a text file that tells it to recompute this value.

    1. Your point about not being able to have good git version control with the json file format that uses is correct and well taken. However, incredible effort is put in making sure that old files are readable in every new version of this app (it’s built right into the test suite that is run on every commit to the repo). Every file still opens, even those created when the app was first publicly released in July 2021. If an old file doesn’t open, that’s considered a bug and will be addressed. Also, the open source nature of this project does mitigate some of the archival risk as well. If I were to pull the rug out from under the users and their old files don’t open in a new version, someone else can fork the project. The Mathcad Prime situation is not a possibility here.

  5. I’m only sad I didn’t come across this sooner, finally a replacement for mathcad (not counting smath).
    When I started my first job there was a split between the experienced guys with perpetual licenses of mathcad and the newer engineers stuck with mathcad express because of the shift to a subscription model which my company wouldn’t pay for. The file formats were incompatible between the two.
    Then after a couple years the company stopped letting people install express on new machines because of the EULA.
    Mathcad is a great tool owned by a company executing user unfriendly processes. I’m glad there’s a replacement.

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