You go out for dinner with some friends and then have to pay. When the bill comes out, the idea is to make things easy and divide the total amount by the number of people present, so everyone pays and is happy. But not most of the times. For sure, some people did take less then others, maybe some got a cake, some not. Doing the division, on the fly, may not be so trivial and the thing can go into a fight, because is late and everyone wants to go out.
Whopays is the fastest solution. Insert the total amount. Divide people in groups and fill in the "people" count for each group. Check the people total below. Then, give your indication for the amount for each group. The application calculates automatically the group level, and checks if the amounts are enough to pay, if some money will be a tip, or if something still misses.
Then, push "calculate amounts" and the application will try to adjust the amounts entries to satisfy the bill, keeping the desidered group proportions. Since the calculations will be in the way of simplifying your life, without cents, several differen results can be reached pressing more times "calculate amounts".
You can stop at any time and re-adjust entries, to give some money for tip, as you think is correct.
As you start, you'll see a sample bill of 156,00 for 9 people. Group A is 5, group B is 4 people. The amounts are 20 and 12. The total is 148, and still 8 are missing to pay. Press "calculate amounts" twice and the result will be 20 and 14, which solves the fight.