Diablo 4 Masterworking Guide: What It Does and Does Not Do
Masterworking cannot add new affixes to an item. Ever. It takes the affixes your gear already has and makes their numbers bigger. If you came here asking how to masterwork a new stat onto your gear, the simple answer is that the system you want is Tempering, or the Add Affix recipe in the Horadric Cube. Both are covered in their own guides (coming soon).
Now that the biggest misconception is out of the way, here is what Masterworking does do, because it is still one of the largest power gains in the game.
What Is Masterworking
Masterworking is the endgame upgrade system at the Blacksmith. To masterwork, you first have to collect specific materials (
Obducite). After that, you use said materials to upgrade the quality of an item. Upgrading an item increases its Quality, and as Quality goes up, the values of its existing affixes increase with it. A finished, fully masterworked item is dramatically stronger than the same item untouched, with the exact same affixes at higher numbers.
It works on Legendary, Unique, and Mythic items, and unlike the old system, an item no longer needs to be tempered first.
How to Unlock Masterworking
Masterworking unlocks itself. The first time you pick up Obducite, the base material, the Masterworking tab appears at the Blacksmith, and Tempering comes with it. There is no unlock quest, no Pit requirement, and nothing else to activate.
If you read somewhere that you need to clear a Tier 46 Nightmare Dungeon and unlock the Pit first, you found a guide from 2024. That path was removed seasons ago, and it is, unfortunately, one of the most common pieces of stale advice still ranking in search.
Farming Obducite
If you want to focus solely on getting materials for Masterworking, your Obducite per hour is basically your masterworking speed. The current main sources:
Nightmare Dungeons. Especially with the Treasure Breach sigil affix (which fills the run with Treasure Goblins and showers Obducite), or a guaranteed Horadric Strongroom. Craft Sigils at the Occultist to fish for the good affixes!
Kurast Undercity with a
Tribute of Refinement.Infernal Hordes. Just make sure to open the Spoils of Materials at the end of a run.
Mercenary bartering (worth a daily check; occasionally has materials.)
The Pit is not in this list because it no longer drops Obducite as its normal completion reward, so it is not a dedicated Masterworking farm anymore.
Season 15 tip → Spend your Smoldering Ashes on the Urn of Masterworking, as it gives you a chance to receive additional
Quality and the Capstone Bonus
Each Masterwork increases the item's Quality by a random 2 to 5, up to the cap of 25. Every point of Quality adds 1% to all affix values and 1% to the item's base stats, so a finished item is 25% above where it started, with the Capstone added on top.
At Quality 25, the item earns its Capstone Bonus: a 50% boost applied to one randomly chosen affix, which can land on a regular affix, a tempered affix, or a Greater Affix on the item. Random is the keyword, and that is why the next section exists.
Rerolling the Capstone With Neathiron
If the Capstone lands on the wrong affix, you can reroll it. The reroll costs Obducite, gold, and 
Neathiron, and it does not affect your Quality progress. Neathiron drops from late-game content, such as farming the open world (e.g., Helltides) in Torment difficulty IV or higher, World Bosses, Bartuc in Infernal Hordes, Astaroth in Escalation Dungeons, and Belial. On a build-defining item, rerolling until the Capstone hits your ideal stat is standard practice, the same patience game as the Greater Affix temper loop. Materials spent on rerolls are not refunded.
Something else worth knowing is that the Capstone Bonus can stack on top of a Greater Affix if it lands on one. A GA (Greater Affix) with the Capstone on it is the strongest version of an affix the game can produce, and it is the end goal of the whole crafting pipeline for that slot.
You Cannot Reset Quality Anymore
The old system that many players still know let you reset an item's Masterworking and start over. That is gone. Quality levels cannot be reset, and the only do-over the system offers is the Capstone reroll above. So plan accordingly, because the item you masterwork is the item you finish, which means you should finalize your temper and enchant before spending serious Obducite.
Quick Answers
How do you unlock Masterworking? You do not. Pick up Obducite anywhere, and the tab appears at the Blacksmith automatically.
Does masterworking work on tempered affixes? Yes, tempered affixes gain Quality like the rest, and if you reroll the temper later, the new temper inherits the rank.
Should I masterwork before or after tempering? After. Make sure you are happy with the temper first, or you risk paying for Quality on an affix you replace. Full reasoning in the gear upgrade order guide (coming soon).
Can masterworking create a Greater Affix? No. GAs come from drops, gambling, temper rolls, and certain Transfiguration outcomes. The complete list is in the Greater Affix guide.