Just Loot build planner
Build the character before you grind for it. Put in the gear you have or the gear you are chasing, see the stats it actually gives you, then send it into a fight and watch what happens round by round.
Fill the slots and the middle panel keeps up: Health, Attack, Defense, Armor, Resist, crit, masteries, the lot. Capped stats are marked, so you stop stacking Crit Damage at 300% instead of burning four more affixes on it.
Hover a stat and you get the formula behind it, your numbers inside that formula, and which items fed it.

Pick a type, rarity, depth and quality. Affix values, Defense and Score come out of the game's own formulas, so a Legendary chest at depth 20,000 gets the numbers the game would have given it.

Choose a dungeon depth, the training dummy, or another player's build in PvP, then hit Fight. The log reads out every round: what hit you, what you hit back with, which Legendary fired and what it did.

Set the species, rarity and level and you get the family bonus and mastery that come with it.

Saved builds live in your browser. You do not need an account for the planning: crafting, equipping, fights and saving all work logged out, and you can load anything from Community Builds without signing in.
Log in with Discord and you can publish your own, vote and use the chat. Every build gets a share link that unfurls with its name, archetype, Score, DPR, effects and pet.

Global chat and direct messages, with builds sharable straight into a conversation. Open it fullscreen when a thread is worth reading properly.
Leading a raid in Just Loot? Raid runs its applications, roster and weekly XP, with a Discord bot for your server.

Just Build is fan-made and not affiliated with Marlo Interactive or Just Loot in any way.