GURPS Calculator

And a happy GURPSDay to you and yours!

I have a convention coming up next weekend that I’m still furiously prepping for, but I wanted to make a quick post to heap much-deserved praises on the GURPS Calculator web app. It really is 9.1 kg of awesome in a 5.8 kg sack, and I wholeheartedly suggest you check it out for streamlining your games at the table.

I reviewed a version of this when it was still in its infancy as an Android app (and have reused some of that here), but the app today has many more features and has grown tremendously. The fact that the Calculator is now a web app instead of an Android app cannot be helped, but that really is the only drawback — you must have an active internet connection to access the Calculator (though it works fine on desktop, laptop, tablet, or phone).

Once you’re at the site, you’ll see a navigation bar at the top of the page.

Starting from the right, the first item is a super basic dice roller labeled “Roll 3d!” This is extremely handy when you’re using the Calculator for other things but just need a quick roll. There are no options, no frills, you don’t need to navigate to another page… just tap the button and it rolls 3d6.

Next is a drop-down for “Settings,” letting you do things like change your password, change the color scheme (though I personally prefer the default “Cerulean”), choose whether to use optional rules from Matrial Arts, things like that.

And then, under “Tools,” is where the magic happens. It’s glorious.

  • Dice Roller: A GURPS-friendly and easy-to-use dice roller. One of the best parts is, you can enter how many times you need the dice rolled and what the target number is. So, if you have a mob of 10 pirate NPCs all with skill 12, you can just enter the info and hit the Calculate button to see how many hit and how many miss (as well as what their individual rolls were and the margins of success/failure). Beautiful.


  • Campaign Manager: You can maintain a list of different Campaigns so you can set different options in the Tracker and keep them separate and organized.
  • Tracker: This can be a huge time saver. In addition to allowing HP and FP tracking (indicating the changing statuses as pass thresholds), the Tracker lets you enter all the details (skill level, damage type and range, hit location, target’s DR, postures of the attacker and defender, everything) of various characters’ attacks so you can then roll each one at the press of a button. For example, here is an Orc swinging his sword (damage 2d) with a skill of 13 at a random hit location against a target with DR of 4. The results after hitting the “Roll” button clearly show the margin of success, the hit location struck, the rolled damage, and the penetrating damage (taking into account both the target’s DR and the hit locations wound modifier). BAM!


  • The next few entries all let you enter the data necessary to calculate certain values and then do the calculations for you: Collision and Fall Damage (p. 430-431), Demolitions (p. 415), Jumping Distance (p. 352), and Throwing Distance (p. 355). Super helpful.
  • Improvement Through Study: Uses the rules from pp. 292-294 to calculate the ins and outs of improving skills during a character’s “down time.”
  • Search Books Indices: Just what it sounds like — an integrated version of the GURPS Index Imp, allowing you to search the indices of all the GURPS 4th books currently included.
  • Trait Sorter: Similar to the official one — allows you to generate custom lists of which traits are Allowed, Not Allowed, Recommended, Required, etc.
  • Treasure Generator: Automatic calculation of treasure hoards according to the rules and tables in Dungeon Fantasy 8: Treasure Tables.


  • Music: Uses collections of ambient loops from Spotify to quickly put together background music.

And, finally, the “Characters” drop-down actually lets you import entire characters into the Calculator from the venerable GURPS Character Sheet character builder which, among other things, allows you to roll against any skill, attribute, attack, or defense at the click of a button. For example, all three shots from this RoF 3 pistol successfully hit… rolled and penetrating damage has already been calculated for each hit:



As you can see, the GURPS Calculator puts a huge number of options at your fingertips. I love it, my players love it… and who knows, maybe you’ll love it too! At the very least, it’s worth a peek… I suspect you won’t be sorry. (If you do love it, the creator has a Patreon account… and it’s close to unlocking support for importing GCA character files!)

Happy GURPSDay!
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