How Skill Checks work in Rogue Trader

Coming from Baldur's Gate 3 and confused by Rogue Trader's skill checks? Here's a quick overview how skill checks are calculated.

Calculating outcomes of a skill check

Note: This guide might be outdated at this point. Please check the comments for further information, once you've read through it.

Skill checks in Rogue Trader are conducted with a 1d100 roll (two d10's: one for the tens and one for the single digit). To pass a skill check, your character or companions must roll equal to or less than the associated skill score.

Here is a simple example:


In a conversation with Argenta, our knowledge of the Imperium might open up additional dialogue - thus Lore (Imperium) will be tested against the dice roll.

The party member with the highest relevant skill will automatically be chosen for this test. In the above example, it's my Rogue Trader with a Lore (Imperium) score of 60. We then add or subtract the difficulty modifier. In this case it's +11, indicating that the skill check is of Ordinary difficulty. So, we now have to roll less than or equal to 71 to pass the test, and that's exactly what we did (54), resulting in success. Easy enough right?

To pass a skill check, you have to roll less than or equal to your skill score with a 1d100 dice.

Difficulty modifiers

The difficulty modifier applied to a skill check is based on two values:


Your chosen game difficulty

Story mode: +20%
Normal: +10%
Daring: 0%
Hard: -10%
Unfair: -20%

The difficulty of the skill check

Trivial: +60
Elementary: +50
Simple: +40
Easy: +30

Routine: +20
Ordinary: +10
Challenging: +0
Difficult: –10
Hard: –20

Very Hard: –30
Arduous: –40
Punishing: –50
Hellish: –60

Example: If we play on Normal difficulty, and our skill score is tested against an Ordinary skill check, we get a difficulty modifier of 10+(10*0.10) = +11 added to our skill score.

[Snickers Anyone]

Thanks to both of you, Ozixi Thrill and Demaar, for the additional info. I haven't had a chance to pick up the game again (my ever-growing backlog and RL have no chill) so this guide is definitely outdated by now. I'll probably archive/delete or update it once I had a chance to play a bit more of Rogue Trader.

[Ozixi Thrill]

Two things:
1 - The best way to think of the skill checks is that the dice rolls generate the DC of the check. If you're trying to explain things to BG3 players, at least.

2 - Sometimes, due to narrative reasons, rather than the character best suited to a challenge, a specific character is chosen; And in some cases, the player can force a specific character to perform a check as well - Specifically with interactables. This can matter when you have a character that has re-rolls for a skill but is not the highest ranked in said skill. Or with that one item I got from somewhere.
One example for the above is when Yrlieth tries to convince some other knife-ears of something; Instead of the best Persuation character, it will be her persuation that gets checked.
So it's not entirely correct that the best suited character is picked for a challenge.

[Demaar]

The game now has a really good explanation in the a tutorial popup:
"For example, you are attempting a test with difficulty of -10.

Your character’s Tech-Use skill score is 40.

40 - 10 = 30

Therefore, to succeed on the Tech-Use skill test, you must roll a 30 or less. Any result above 30 will mean failure.

Note that difficulty is calculated from greater to lower values. The greater the difficulty value, the easier it is to pass the test (it is easier to succeed on a difficulty 40 test than on a difficulty 10 test)."

[Rizilliant]

I appreciate the simple explanation

[JUBAMI]

I need to check <skillname>. 1 of my chars have it 162, but game check char with 90, why?

[Snickers Anyone]

Yep, the companion with the highest value will always be used for calculations, as long as they are present in your party. The story might have some checks that can only be rolled by your Rogue Trader but I haven’t encountered any so far.

[Decom]

So if my abelard has high persuasion , itll use his skill instead of mine even though im the one talking ?

[Brock Savage]

@Lexi Rolling under using d100 is a common tabletop RPG mechanic that's been around since at least 1981 and maybe earlier. Off the top of my head, Mothership, Mythras, Call of Cthulhu, Rune Quest, BRP, and all the Fantasy Flight 40k RPGs use d100 roll under.

[Metanoia]

There's a few tabletop games that use a roll under. D&D used to use something like that in THAC0.

[Snickers Anyone]

Yeah it‘s a bit confusing at first (which is why I wrote this guide), but it does have one advantage: You can immediately see your chance to succeed, in percent. For the example screenshot above it‘s 71% - no math skills necessary, kinda neat 😄