Crafting Magical Items

Arcana Proficiency & Study To craft a magic item, you and any assistants must have proficiency in the Arcana skill. You will often also require either the character to be able to study an existing magic item that is similar, or have a schematic, particularly for magic items of higher rarity.
Tools The Magic Item Tools table lists which tool is required to make a magic item of each category. You must use the required tool to make an item and have proficiency with that tool. Any assistants must also have proficiency with it.
Magic Item Tools Item Category: Required Tool Armor: Leatherworker’s Tools, Smith’s Tools, or Weaver’s Tools depending on the kind of armor as noted in the tools’ descriptions Potion: Alchemist’s Supplies or Herbalism Kit Ring: Jeweler’s Tools Rod: Woodcarver’s Tools Scroll: Calligrapher’s Supplies Staff: Woodcarver’s Tools Wand: Woodcarver’s Tools Weapon: Leatherworker’s Tools, Smith’s Tools, or Woodcarver’s Tools depending on the kind of weapon as noted in the tools’ descriptions Wondrous Item: Tinker’s Tools or the tool required to make the nonmagical item on which the magic item is based
Spells If a magic item allows its user to cast any spells from it, you must have all those spells prepared every day you spend crafting the item.
Time and Cost Crafting a magic item takes an amount of time and money based on the item’s rarity as shown in the Magic Item Crafting Time and Cost table.
Work per Day. For each day of crafting, you must work for 8 hours. If an item requires multiple days, those days needn’t be consecutive.
Assistants. Characters can combine their efforts to shorten the crafting time. Divide the time needed to create an item by the number of characters working on it. Normally, only one other character can assist you, but the DM might allow more assistants.
Raw Materials. The cost in the table represents the raw materials needed to make a magic item. The DM determines whether appropriate raw materials are available. In a city, there is a 75 percent chance that the materials are available, and in any other settlement, that chance is 25 percent. If materials aren’t available, you must wait at least 7 days before checking on the availability again.
If a magic item incorporates an item that has a purchase cost (such as a weapon or a suit of armor), you must also pay that entire cost or craft that item using the rules in the Player’s Handbook. For example, to make +1 Armor (Plate Armor), you must pay 3,500 GP or pay 2,000 GP and craft the armor.
Magic Item Crafting Time and Cost Item Rarity        Time*          Cost* Common           5 days         50 GP Uncommon       10 days        200 GP Rare                50 days        2,000 GP Very Rare         125 days      20,000 GP Legendary        250 days      100,000 GP *The time and cost are halved for a consumable item other than a Spell Scroll
When creating a magical item, there are opportunities to add some special features - like the weapon reflecting the item's creator or intended user, the history, minor properties and quirks. The crafter may be able to exert some influence over some of these special features but usually, it is difficult to know what the special features of the item will be in advance.