Yesterday I went out for pizza with friends. I opted for a childs size thin crust pizza. No sauce, skimpy on the cheese, had feta and black olive for toppings and fresh tomatoes.
I wouldn't even know where to begin to calculate the calories, anyone have access to a calorie calculator that allows me to put in the size and toppings. I could try the recipe tool but I wouldn't know how to enter in the crust.
Many pizza chains have nutritional information on their websites or available at the restaurant.
This wasn't a pizza chain, it was a mom and pop type place and they don't have nutritional info available.
In that case I'd guesstimate how much toppings you had and use the calorie count calculator to enter those manually.
A quick google search resulted in a hit for a 7" pre-formed pizza dough and said it was 330 calories. Use that as a baseline to approximate how many would be in a child's size pizza - along with the toppings you listed.
That's what I'd do.