Sunday, July 20, 2014

How to split bills with friends

I often come across situations wherein I have to divide my expenses with the friends. If the group size is two then the things go smoothly and each one can calculate how much one has to pay. But if it exceeds two then it becomes a bit difficult. It become more complex if the expenses are spent unequally. For example if you go to an ice-cream shop and each one selects one in a different range. Then suppose you proceed to a chocolate shop and again the price of chocolates purchased are different and this time your friend pays for the group.

I have (aa correction rediscovered) a simple method to resolve all the owing at one shot by simply organizing and calculating in a particular way. Use of an excel sheet/spread sheet is recommended to implement the method.

I will demonstrate the method with an example.
Lets imagine you have a group of three friends and are going for a movie. Let the friends are A, B and C.
The following is the list of payments done by them
1. Movie Ticket purchased for all by A : 461 Rs.
2. Parking ticket 1 purchased by A : 100 Rs
3. Parking ticket 2 purchased by C : 100 Rs
    * They had two vehicles and decide to spread the charges equally.
4. 3D goggle charges payed by A  for all : 75 Rs
5. Sugarcane juice purchased by B, A drinks 2 glasses, B drinks 2 glasses and C takes only 1: 60 (12 rs/glass)
6. A lends 10 rs to C to enable let him to purchase a hot coffee.

Step 1
Write your expenses as depicted below.

S.No Expenses Amount A B C
1 Ticket 461
2 Parking1 100
3 Parking2 100
4 Goggles 75
5 Sugarcane 60
6 Lend 10

Step 2
Now for each row divide the expense in columns A, B and C such that each cell shows either how much amount was spent on the corresponding person (use a negative sign) or how much amount was spent by that particular person on others(use a positive sign).

S.No Expenses Amount A B C
1 Ticket 461 307.3333 -153.667 -153.667
2 Parking1 100 66.66667 -33.3333 -33.3333
3 Parking2 100 -33.3333 -33.3333 66.66667
4 Goggles 75 50 -25 -25
5 Sugarcane 60 -24 36 -12
6 Lend 10 10 0 -10

Step 3
The next step is to compute the total for each colum A, B and C.

  1. So for our example B ows other (negative sign) a sum of 209 rupees. Similarly C ows others a sum of 167 rupees. A needs to get a sum of 376 rupees from others. If you add all the entries in last row the total comes as zero which shows that it is balanced. Similarly all the other rows are also balance(Add only the A, B & C column entries).


S.No Expenses Amount A B C
1 Ticket 461 307.3333 -153.667 -153.667
2 Parking1 100 66.66667 -33.3333 -33.3333
3 Parking2 100 -33.3333 -33.3333 66.66667
4 Goggles 75 50 -25 -25
5 Sugarcane 60 -24 36 -12
6 Lend 10 10 0 -10
Total 376.6667 -209.333 -167.333
You can download the sample excel sheet from here.