What is the highest solo ability check result at level 19?

Question

Highest possible ability check is discussed in this QA. However, answers to that are rather extreme. I am looking for a value that is, hopefully, more grounded, and might realistically happen in any highest tier game. For this reason, specs are these:

• The effective d20 shows 20
• Level 19, so proficiency bonus +6, no Epic Boons
• Character was created using the Standard Array for ability scores
• Maximum ability scores of 20
• Feats allowed
• Single class, or 2- or 3-class if multi-classed
• Must be achievable by one player controlling one PC and their resources, without direct help of NPCs or other PCs. A familiar, a companion or a Simulacrum is ok (but see below)
• Check must be repeatable daily, indefinitely, at a maximum cost of 1000 GP per day
• Any magic items allowed, but only 1 legendary item

Ok, that's quite a lot of bullet points, but I hope it'll make answering this actually easier, with fewer things to consider... I hope it allows any reasonable character, while closing any "infinite" or otherwise broken combos. If you can go higher by breaking some of these a bit, feel free to add that into an answer, though.

Answer 1

A 19th-level Artificer can roll 51 on a check to pick a lock with only their own class features

Suppose we have a 19th-level artificer with 20 Int and 20 Dex (+5 modifier on both, easily achieved with the standard array, 5 ASIs, and any racial bonus to either stat). They have infused their Gloves of Thievery and cast Guidance on themself. They step up to a lock and attempt to pick it, using Flash of Genius to add their Intelligence modifier to the roll. The resulting modifiers are +5 (Dex), +12 (Tool Expertise), +5 (Gloves of Thievery), +5 (INT, Flash of Genius), and +1d4 (Guidance). The maximum possible roll is 20 + 4 + 5 + 12 + 5 + 5 = 51. If you don't want to assume a good roll for the d4, then as long as the d20 is a 20, the roll is guaranteed to be at least 48.

(The minimum possible roll, incidentally, is 29, which only has a 1/80 chance to occur (rolling 1 on both dice). So assuming the lock is "nearly impossible" to pick (DC 30), the artificer has a 79/80 chance of success on this check, and they most likely won't even need to use Flash of Genius on it, since they can decide to do so after rolling.)

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Going beyond just class features, the artificer could acquire a Stone of Good Luck and (with somewhat more difficulty) an Ioun Stone of Mastery to add another +1 and +2 respectively to the check, bumping the maximum roll to 54 (and the minimum roll to 32, thus giving a 100% success rate on picking a nearly impossible lock).

(Thanks to user Groody the Hobgoblin for the added magic items.)

Answer 2

The maximum result for a skill check is 54

The Skill User

Our character is a Dimir Operative from Theros, a 19th level Wizard, a Skill Expert, and a Magic Initiate cleric making a Dexterity (Stealth) check.

The Features

• Dimir Guild Spells gives access to the spell pass without trace
• Wizard levels give access to the spell simulacrum, and the feature Spell Mastery
• Skill Expert gives us a doubled Proficiency Bonus
• Magic Intiate gives access to the spell guidance

The Gear

• A luckstone
• An Ioun Stone of mastery

The Calculation

• Dexterity score is 20 (or a +5 modifier)
• pass without trace adds 10 (cast by our simulacrum using Spell Mastery)
• guidance adds 1d4 (maximum 4)
• Proficiency adds 12 (thanks to Skill Expert)
• luckstone adds 1
• Ioun Stone of mastery adds 2 (thanks to Skill Expert)
• Roll a 20

Grand total: 54

Answer 3

8th level Circle of Dreams Druid + 11th level Rogue: Minimum 46 Stealth, Maximum 59 Stealth

Race: Mark of the Shadow Elf (Cunning Intuition): Can add 1d4 to Dexterity (Stealth) checks

Magic Items:

• Staff of the Woodlands (Pass Without Trace cast for free)
• Ioun Stone of Mastery (+2)
• Luckstone (+1)

Features:

• 6th level Druid: Hearth of Moonlight and Shadow (allows you to add +5 to Dexterity (Stealth) or Wisdom (Perception) checks while in a short of long rest)

Feats:

• Skill Expert (Expertise in chosen Skill)

The Breakdown

• d20 roll: 20 (Minimum 10 from Reliable Talent)
• Deterity Modifier: 5
• Pass without a Trace: 10
• Mark of the Shadow Elf Cunning Intuition Feature: 4 (technically 1d4)
• Skill Expert Doubling Proficiency Bonus: 12
• Hearth of Moonlight and Shadow: +5
• Luck Stone: 1
• Ioun Stone of Mastery: 2

Result:

Minimum Stealth: 46

Maximum Stealth: 59

Addendum

Additionally, that minimum stealth is infinitely maintainable since you can chain short rests.

Technically we could choose any other class to Rogue, the Rogue's only contribution in Reliable Talent for the minimum stealth. There are also 2 levels of freedom on the Druid side. So 13 levels of freedom to optimise this further for a higher maximum.

Answer 4

6th level Circle of Dreams Druid + 5th level Wizard + 8th level Artificer: Minimum 37 Stealth, Maximum 68 Stealth

Race: Mark of the Shadow Elf (Cunning Intuition): Can add 1d4 to Dexterity (Stealth) checks

Magic Items:

• Staff of the Woodlands (Pass Without Trace cast for free)
• Ioun Stone of Mastery (+2)
• Luckstone (+1)
• Tome of Clear Thought (+2 to INT for max of 20)
• 3x Tome of Understanding (+6 to WIS for max of 20)
• Gloves of Thievery
• Scroll of Simulacrum

Features:

• 6th level Druid: Hearth of Moonlight and Shadow (allows you to add +5 to Dexterity (Stealth) or Wisdom (Perception) checks while in a short of long rest)
• 7th level Artificer: Flash of Genius
• Tasha's Optional Racial ASIs: +2 DEX +1 INT
• Tool Expertise: Artificer
• Druid: Guidance Cantrip, Enhance Ability Spell

Feats:

• Skill Expert (Expertise in chosen Skill)

The Build

Standard array:

• STR: 8

• DEX: 15

• CON: 12

• INT: 14

• WIS: 13

• CHA: 10

• Tasha's Optional Racial ASIs: +2 DEX +1 INT

• Artificer ASI #1: +2 INT

• Artificer ASI #2: Skill Expert: +1 WIS

• Wizard ASI: +2 DEX

• Druid ASI: +1 DEX +1 INT

• Tome of Clear Thought: +2 INT

• 3x Tome of Understanding: +6 WIS

Final array:

• STR: 8
• DEX: 20
• CON: 12
• INT: 20
• WIS: 20
• CHA: 10

Skill Proficiencies:

• Arcana
• History
• Investigation
• Perception
• Stealth (Expertise from Skill Expert)

Artificer Infusion:

• Boots of Elvenkind (Advantage on Stealth)

Since we have 8th level slots from the combination of classes we have, we can cast the Scroll of Simulacrum to make a simulacrum of ourselves who can cast guidance for us.

Note: if the DM says we can't because the Max Wizard spell we can scribe is 3rd level and we need to make the Intelligence check, then we can use the following combination to "guarantee" it passes: +5 INT mod + 5 Flash of Genius +advantage from Enhance Ability + 1 from Luckstone, which results in a 93.8% chance of succeeding on the check (as you only need a 6 or higher on the dice to succeed). If we fail, we just break out another scroll and try again (because 7th level spell scrolls are only Very Rare)

The Breakdown

• d20 roll: 20
• Deterity Modifier: +5
• Pass without a Trace (Staff of the Woodlands): +10
• Mark of the Shadow Elf Cunning Intuition Feature: +4 (1d4)
• Skill Expert Doubling Base Proficiency Bonus: +12
• Hearth of Moonlight and Shadow: +5
• Luck Stone: +1
• Ioun Stone of Mastery: +2 (due to Expertise doubling proficiency bonus))
• Flash of Genius: +5
• Guidance from Simulacrum: 4 (1d4)

Result:

Maximum Stealth: 68

Average Stealth (with Flash of Genius): 58.25 (due to advantage from Boots of Elvenkind)

Average Stealth (without Flash of Genius): 53.25 (due to advantage from Boots of Elvenkind)

Minimum Stealth: 37 (Roll 1s on all dice and don't use Flash of Genius)

Bonus Points:

This Character will also have a minimum Thieves Tools check of 27 (1 [d20] + 5 [DEX] + 12 [Tool Proficiency] +5 [Gloves of Thievery] +1 [Luckstone] + 2 [Ioun Stone of Mastery] + 1 [Guidance]) , or 32 if they use Flash of Genius, with a maximum of 54.

Addendum

Additionally, that minimum stealth is infinitely maintainable since you can chain short rests.

Answer 5

Sorry for the necro but a tech inspired by @smbailey's answer: 914 (1662 with a little bit more rules-bending).

Character Build:

Race:

• Dhampir

Class:

• College of Swords Bard 17
• Grave Cleric 2

Background:

• Dimir Operative

Our Items:

• Insignia of Claws
• Amulet of Health (Attunement)
• Ioun Stone of Mastery (Attunement)
• Luck Stone (Attunement)

Ability scores: Largely irrelevant but we will be using smbailey's stats above with a few modifications. Using 27 point buy:

• STR: 10
• DEX: 13 [14 from +1 for Piercer (Bard 12 Feat)]
• CON: 8 [19 with Amulet of Health]
• INT: 12
• WIS: 15 (16 from +1 Wis Tasha's custom stats)
• CHA: 14 (20 from +2 Cha Tasha's custom stats, +2 Cha Bard 4 Attribute bonus, +2 Cha Bard 8 Attribute bonus)

Spells/Abilities Used:

• 9th level Spell Slot: Conjure Animals (Stolen by Magical Secrets)
• 2nd level Spell Slot: Find Steed (Stolen by Magical Secrets)
• Bardic Inspiration: Blade Flourish -- Slashing Flourish
• Channel Divinity: Path to the Grave
• 2nd level Spell Slot: Pass Without Trace (From Dimir Operative background)
• Dhampir Bite

Steps:

• Conjure animals can summon 32 creatures (1/8th challenge rating or lower) at level 9. (Note, the DM chooses the animal and can choose one to screw with you. But since we are trying to just see the highest possible, we are assuming a nice DM... Don't try this on a nice DM). We are going to assume these are rats in honor of the term "Bag of Rats".

• Order all of our rats to stand next to us. 4 Tiny Creatures can fit into a single 5ft space. There are 8 spaces around us (not counting height difference) which can accommodate 32 tiny creatures.

• Summon and ride your mount.

• Channel Divinity on ourselves so we make ourselves vulnerable to the next instance of damage we take.

• Dhampir Bite:

Your fanged bite is a natural weapon, which counts as a simple melee weapon with which you are proficient.

You gain a bonus to the next ability check or attack roll you make; the bonus equals the piercing damage dealt by the bite.

It is important here to note that the ability doesn't specify that all the damage needs to be done to a single creature, but rather by the bite itself.

• Blade Flourish: Slashing Flourish

You can expend one use of your Bardic Inspiration to cause the weapon to deal extra damage to the target you hit and to any other creature of your choice that you can see within 5 feet of you. The damage equals the number you roll on the Bardic Inspiration die.

Average Damage on a hit (No Crit):

• 2*1d4 = 5 (bite yourself, Vulnerable due to Channel Divinity)
• 2*1d12 = 13 (Blade Flourish yourself, Vulnerable due to Channel Divinity)
• 32d12 = 208 (Blade Flourish all the rats)
• 1*1d12 = 6.5 (Blade Flourish on your steed)
• 2*3 = 8 (Con, Vulnerable due to Channel Divinity)
• 2*1 = 2 (Insignia of Claws, Vulnerable due to Channel Divinity)

This is on average 242.5 Damage

Maximum damage On a Crit

• 2*2d4 = 16
• 2*2d12 = 48
• 2*1d4 = 8 (Piercer, Vulnerable due to Channel Divinity)
• 64d12 = 768
• 2d12 = 13
• 2*4 = 8
• 2*1 = 2

This is equal to 863 Damage

Our Total Stealth Check:

• 20 (1d20)
• 2 (Dex)
• 12 (Proficiency)
• 863 (Dhampir Bite)
• 1 (Luckstone)
• 2 (Ioun stone of Mastery + Expertise)
• 10 (Pass without Trace, We are no longer concentrating in Conjure Animals so we can switch to this)

Total Final Persuasion: 910

If we use Tomes to Tome our way to 20 in all stats, that would be +1 more Con and +3 more Dex or 914 total.

---

Tech...

And a little rule-bending. We can steal another 2 spells with magical secrets at 14. We can steal Magic Jar, and Simulacrum for good measure.

We can Wish for Simulacrum (since Simulacrum costs 1500GP) every day. This simulacrum can spend a 7th level spell slot to cast conjure animals for only 24 tiny creatures. Simulacrum can also cast Find Steed. EDIT: See addendum, we can use Scroll of Simulacrum since it isn't a legendary item. This allows the simulacrum to still have its 9th level spell slot

Now comes the fun part. We need to find a Deaths Head of Bhaal. This nice little humanoid friend comes with

Aura of Murder. As long as the death's head is not incapacitated, hostile creatures within 5 feet of it gain vulnerability to piercing damage unless they have resistance or immunity to such damage.

We can magic jar them:

Once you possess a creature's body, you control it. Your game statistics are replaced by the statistics of the creature though you retain your alignment and your Intelligence, Wisdom, and Charisma scores. You retain the benefit of your own class feature. If the target has any class levels, you can't use any of its class features.

Now we have all our spellcasting and Aura of Murder. But all the creatures summoned by you and your simulacrum are friendly not hostile so what should we do? Make Friends with them!

For the duration, you have advantage on all Charisma checks directed at one creature of your choice that isn't hostile toward you. When the spell ends, the creature realizes that you used magic to influence its mood and becomes hostile toward you.

Since our Simulacrum is concentrating on Conjure Animals, we can be free to cast 1 Friends per turn. 24 times. If we do this in a storage closet somewhere, the rats can't flee. You will most likely be taking damage per turn though.

Now we use our combo from above... Average Damage on a hit (No Crit):

• 2*1d4 = 5 (bite yourself, Vulnerable due to Channel Divinity)
• 2*1d12 = 13 (Blade Flourish yourself, Vulnerable due to Channel Divinity)
• 2*24d12 = 312 (Blade Flourish all the rats, Vulnerable due to Aura of Murder)
• 1d12 = 6.5 (Blade Flourish on your steed)
• 1d12 = 6.5 (Blade Flourish on your simulacrum)
• 1d12 = 6.5 (Blade Flourish on your simulacrum's steed)
• 2*4 = 8 (Con, Vulnerable due to Channel Divinity)
• 2*1 = 2 (Insignia of Claws, Vulnerable due to Channel Divinity)

This is on average 359.5 Damage

Maximum damage On a Crit

• 2*2d4 = 16
• 2*2d12 = 48
• 2*1d4 = 8 (Piercer, Vulnerable due to Channel Divinity)
• 2*48d12 = 768
• 2d12 = 13
• 2d12 = 13
• 2d12 = 13
• 2*4 = 8
• 2*1 = 2

or 1273 damage

Our Total Stealth Check: 1320

• 20 (1d20)
• 2 (Dex)
• 12 (Proficiency)
• 1273 (Dhampir Bite)
• 1 (Luckstone)
• 2 (Ioun stone of Mastery + Expertise)
• 10 (Pass without Trace)

1324 if we use Tomes to bring our Con from 19 to 20 and Dex from 14 to 20.

-- EDIT: Stealing the Scroll of Simulacrum idea from above, we can actually increase our number of vulnerable rats back to 32 since we aren't using our 9th level spell slot for it... 1661 is our new total. (1662 with Tomes)

Answer 6

Up to +162 on any check

For this build I steered away from things like using Tomes to boost all the stats, and consumable items, since this has to be repeatable daily. I'm not even sure I've fully optimized it the way it is, and with those it could definitely be optimized further.

The Build

Level 19 Dhampir with the Boros Legionnaire background.

Class Levels

Wizard (Order of Scribes) 13
Fighter (Battle Master) 4
Cleric (Grave Domain) 2

Spells Known

Blinding Smite (3rd, Boros Legionnaire spell)
Mordekainen's Faithful Hound (4th)
Hold Monster (5th)
Simulacrum (7th)

Feats

Piercer
Skill Expert (Investigation)

Items

Insignia of Claws
Bag of Tricks, Rust
+3 Arcane Grimoire (Attuned)
Amulet of Health (Attuned)
Ring of Spell Storing (Attuned by Simulacrum)

Ability Scores

STR 10
DEX 14
CON 8 [19 with Amulet]
INT 20
WIS 13
CHA 16

The Procedure

This takes a bit of setup, but can get a very high bonus on any check, and can be done multiple times per day.

Setup

Prepare for this procedure by casting hold monster into the Ring of Spell Storing worn by your simulacrum.

Step 1

Use action to pull creature out of the Bag of Tricks onto the ground. As soon as it comes out, Simulacrum casts hold monster on the creature using the spell stored in the ring. Spell save DC is 22, best creature WIS is +1, so there is no chance of saving.

Step 2

Simulacrum uses Channel Divinity: Path to the Grave to make the creature vulnerable to all damage from the next attack. You use a bonus action to cast blinding smite using a 4th-level slot, and use Awakened Spellbook to replace the spell's damage type with piercing damage from Mordekainen's faithful hound. As an action, attack with the Dhampir's Vampiric Bite, adding any Battle Master maneuver that increases the damage roll (my favorite is Menacing Attack).

With a +11 to hit and advantage, there is a 1/400 chance to miss (the highest possible AC from the Bag is 12, so only a natural 1 will miss). If this happens, you can use your own Channel Divinity and Action Surge to attempt the bite again on the next turn. If you fail to bite three times (incredibly unlucky), the Channel Divinity wears off, so you'd need to take a short rest and try again. When it does hit, though, the hit is critical due to the paralyzed condition, dealing

(2d4(bite) + 2d8(maneuver) + 1d4(piercer) + 6d8(smite) + 5) * 2 [piercing]

an average of 97 piercing damage (min 32, max 162).

When you attack with the Dhampir's Vampiric Bite ability, you can choose the following option:

You gain a bonus to the next ability check or attack roll you make; the bonus equals the piercing damage dealt by the bite.

Step 3

You can now make any check you want and (since the damage was all piercing damage) add the entire amount of damage from the bite onto the check. For the purposes of this question, I will be making an Intelligence (Investigation) check since we took expertise in that. With a roll of 20, our investigation check comes out to a minimum of

20 + 12(expertise) + 5(INT) + 32(bite) = 69

and a maximum of

20 + 12(expertise) + 5(INT) + 162 = 199

with an average check of 134. This whole process can be done up to three times per day, using Arcane Recovery to get a third 5th-level spell slot. It could also be done using hold person if there are any tasty looking humanoids around.

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_{NOTE: This build relies upon the ruling that a simulacrum regains expended resources, specifically Channel Divinity uses and Maneuver dice in this case. Answers to this question indicate this is the RAW ruling, but Crawford tweets (which aren't official rulings anyway) indicate RAI is different. Some DMs may rule against this.}

Answer 7

I had to jump on this Dhampir synergy to get a new maximum of 5,126

The Skill User

Our character is a level 17 Dhampir College of Swords Bard and level 2 Grave Domain cleric who has uncovered the find familiar, pass without trace, wall of stone, and demiplane spells via Magical Secrets. He is a Stealth Skill Expert and has the Piercer feat. He has also found and cast planar binding on 26 chwingas.

The Gear

• a cloak of the manta ray
• a luckstone
• an insignia of claws
• an Ioun Stone of Mastery
• a ring of spell storing

The Chwingas

The crux of our strategy involves using the chwinga's Magical Gift ability:

The chwinga targets a humanoid it can see within 5 feet of it. The target gains a supernatural charm of the DM's choice.

...to give a bunch of humanoids the ability to cast conjure animals via the Charm of Animal Conjuring.

Our "humanoids" are actually familiars that each chwinga has found via the ring of spell storing storing find familiar. Our Dhampir has cast true polymorph on each of them so they are valid targets for Magical Gift.

The chwinga and familiars hang out in a demiplane our Dhampir created that also contains a 15x15 pool of water held in by walls created with wall of stone. This doubles as a nice leisure area for the chwinga and the location for the charging of our Dhampir.

The Procedure

When our Dhampir is ready to make their ability check, they cast demiplane to visit our chwinga and initiate this procedure:

1. Our Dhampir throws on the cloak of the manta ray and hops into the pool floating in the middle.
2. The chwinga call fourth their humanoid familiars from their pocket dimensions.
3. Each chwinga uses Magical Gift on their familiar.
4. Each familiar casts conjure animals to conjure 8 crabs in the pool.
5. The Dhampir has the biggest feast of his life using Blade Flourish to deal piercing damage to himself and all of the crabs.
6. The Dhampir uses Path to the Grave on himself.

The Bite

Vampiric Bite says:

You gain a bonus to the next ability check or attack roll you make; the bonus equals the piercing damage dealt by the bite.

With Blade Flourish, we deal damage to all of the crabs so our maximum damage is:

• 2d4 to self (and critical hit)
• 1d4 to self (Piercer feat)
• 2d12 to self (Blade Flourish and critical hit)
• 5 to self (Constitution)
• 1 to self (insignia of claws)
• 416d12 to 208 crabs (Blade Flourish and critical hit)

All of the self damage is doubled thanks to Path to the Grave, so our maximum is:

$$2*(3*4+2*12+6) + 416*12 = 5076$$

The Skill

• Ability score is 20 (or a +5 modifier)
• pass without trace adds 10
• Proficiency adds 12 (thanks to Skill Expert)
• luckstone adds 1
• Ioun Stone of mastery adds 2 (thanks to Skill Expert)
• Vampiric Bite adds 5,076
• Roll a 20

Grand total: 5,126