Use Calculator on Apple Watch Ultra
In the Calculator app 
, you can perform basic arithmetic calculations. You can also quickly calculate a tip and split the check.
Siri: Say something like: “What’s 73 times 9?” or “What’s 18 percent of 225?”
Perform a quick calculation
Open the Calculator app
on your Apple Watch Ultra.Tap numbers and operators to get a result.
Split the check and calculate a tip
Open the Calculator app
on your Apple Watch Ultra.Enter the total amount of the bill, then tap Tip.
Turn the Digital Crown to choose a tip percentage.
Tap People, then turn the Digital Crown to enter the number of people sharing the bill.
You see the tip amount, the total amount, and how much each person owes if the bill is split evenly.
Note: The Tip feature is not available in all regions.
Note: If you remove the Calculator app from your iPhone, it’s also removed from Apple Watch Ultra.