For the Watt Trader tool to funtion properly, you need to save the game after each day that passes. Alternatively, see section Speed Up the Results.
This calculator is a tool to determine: (a) the day when the Watt Traders in the Sword & Shield Wild Area will have a specific Technical Record (TR) or Poké Ball (ball) for purchase; and (b) the raids in the Wild Area which will drop your desired TR. The method used to search (Watt Traders or raids) can be selected from the appropriate dropdown.
Usage of this tool in Watt Trader mode is as follows:
Enter the location of your reference Watt Trader. There are 7 in the Wild Area: Meetup Spot, East Lake Axewell, Dappled Grove, Giant's Seat, Bridge Field, Hammerlocke Hills, and Giant's Cap.
Enter the first TR your reference Watt Trader is selling. This is the one listed first in his offerings, not necessarily the lowest TR number. You can type in the box to filter the options.
Enter what you'd like to search for:
Enter the TR you'd like the purchase. You can type in the box to filter the options.
Alternatively, you can select the Poké Ball you'd like to purcase from the appropriate dropdown.
Click the button to search for either your desired TR or your desired ball. The buttons are labeled appropriately.
Usage of this tool in raid mode is as follows:
Choose your game version from the dropdown.
Choose your desired TR from the dropdown.
Click the button to search for the raids that will drop your desired TR. The raid locations will show up as dots on the map.
Red dots correspond to common (red beam) raids.
Purple dots correspond to rare (purple beam) raids.
Magenta dots indicate the TR will be dropped from both common and rare beam Pokémon at this location.
Click on the den to display the Pokémon that will drop your desired TR. They are printed in the "Results" section.
Note that event raids are not supported.
In Watt Trader mode, the tool will output how many days into the future your desired TR/ball will be sold and at which location. "After 0 day(s)..." refers to today. "After 1 day(s)..." refers to tomorrow. "After 2 day(s)..." is the day after tomorrow. And so forth. For your convenience a picture of the location of the Watt Trader is included as well.
In raid mode, the dens in which your desired TR are dropped will be displayed on the map, color-coded by the rarity of the beam required. Magenta means both common and rare raids will drop your TR at the location. Click the dot to display the Pokémon that will drop your TR in the Results section.
The time needed to wait for your desired TR/ball can be skipped by using a glitch in the Sword & Shield games. This glitch allows you to change the clock on your Switch system settings while making the game think a full day has passed. The steps are as follows:
Find an active den in the Wild Area. It is recommended to use a den activated by a Wishing Piece if you need to skip more than 1 day for your desired TR/ball.
Click A on the den, and begin searching for partners ("Invite others")
While searching, press the home button and navigate to the date and time settings (System Settings > System > Date and Time)
Turn off Synchronize Clock via Internet and advance the day
Click "OK" to confirm the date change
Return to the game and back out of the den (return to the overworld)
Repeat until you have skipped the correct number of days