# Automatic/calculated sheet attributes

March 15, 2019 ### That’s a cool character you have there. But it can do math?

Most RPG systems have some fields that are calculated based on the value of other fields. For example, in D&D, ability modifiers are calculated based on the ability score, using the formula `(ability - 10)/2` (rounded down). If you apply the formula for an ability score of `13`, you will end up with a `+1` modifier.

You can configure you mRPG character sheet to have those automatic values calculated for you, so you can play more and let mRPG do the math (very complex math).

### Example: GURPS movement

In GURPS, characters have a movement field (mvnt), that is calculated using the formula `(HT + DX)/4`.

So let’s start by creating a simplified GURPs character sheet: #### ⭐️ TIP

You can learn more about character sheet templates in this guide: How to create a character sheet template

The character sheet have all the fields wee need to calculate the character movement: `HT` (Health - 11) and `DX` (Dexterity - 13). To calculate that you need to go to a store next to you, buy a calculator, calculate the movement using the formula `(HT + DX)/4` = `(11 + 13) / 4` = `6` and then set the value in the `Mvnt` field. That is just too much work!

### Teaching mRPG how to do it

A better way would be letting mRPG do all that for you (the math part, not buying a calculator for your). Follow these steps:

• Access the field you want to turn into a math formula in you character sheet
• Turn on the `Use dice/math expression`
• Now type the formula. You can reference other sheet attributes surrounding them by `:` (TIP: if you type a `:`, all fields and values of your character sheet will appear for you to select)
• For this example, use this formula: `(:ht: + :dx:)/4`
• You should see a preview of the result as you type the formula
• Hit the `Save` button (this step is VERY important, maybe I’ll do a whole tutorial about it. I shall call it “THINGS DON’T WORK IF YOU DON’T SAVE THEM”) Once you go back to the character sheet you will notice that the `Mvnt` field is now blue, meaning that is is a calculated field. See the next image: If you change the value of any of the related fields (`HT` or `DX`) you will see that the `Mvnt` field will be automatically updated! Science!

### More math and other stuff

You can add functions to round values, make simple conditionals, roll dice and other crazy stuff (OBS: buying a calculator for you is not included). Check and test those functions and dice rolls in the dice reference.

If you are the GM of a campaign you can configure the default value of a field to be a formula. That way, all characters created in your campaign will be able to do math and your playesr will only need to fill the sheet!

That’all! Now go roll some dice.