From WikiDotMako

To handle costs on the trip, we are using a combined debt pool that everyone who has stayed at 71 or 73 Vesturgata is automatically entered into. Although this is designed for apartment rent and groceries, we can use the same system to deal with personal or sub-group debts (e.g., paying for a rented car).

We will need everything to be written in a book by the night of Wednesday January 12th and will compute the final numbers on the morning of January 13th. We cannot accommodate late debts. Missing the deadline for a group debt will likely mean that you don't get paid back.

Group costs[edit]

We are going to dividing up both the rent for 71 and 73 Vesturgata and general food costs from 12/30 through 1/13 between everyone -- weighted by the number of days that each person has stayed in the two apartments.

That means we need all receipts for groceries, toilet paper, and any group costs for this two week period. If you have not yet added these receipts to the notebooks, please do that now.

These notesbooks are in both 71 and 73 Vesturgata that have been set up the whole trip for the purpose of collecting debts. If you are have lost a receipt, write a little note that in the book to mention that.

If you can, please list the vegan and non-components portions of grocery bills separately so we don't charge the vegans for the cheese and eggs.

If you have already left but have things that need to make it into the notebook, send contact Mako in the next 36 hours and he'll will make sure it is added.

Individual or subgroup debts[edit]

The way we are dividing up costs means we can also accommodate individual or subgroup debts within the larger pool. Since almost everyone owes money for rent, you can think of these as one sub-group of people paying down an individual's debt as a way of "paying them back" for an expense they incurred. If folks are also happy just handling these debts outside of our system or have already dealt with them, that's great too.

To handle individual or sub-group debts, you should add them to the notebooks as you would any group expense. The only difference is that you should also clearly list the set of recipients or payees in a line under the entry in the notebook. For example, if Mako rented a car for 4000 ISK and it was used by Mako, Mika, Erik, and Danny, you would note that on the sheet (i.e., Mako would be listed on both sides). If Mako just gave 4000 ISK to Mika, Mako would be the "purchaser" and Mika would be the payee. Please use the description section to make it clear what is going on if things are at all unclear. Unlike group debts, sub-group debts will not be weighted by the number of days people are staying but just divided evenly among the payees. If you want them to be weighted by days, note that clearly and it will happen.

If there is something weird or special that needs to be handled, get in contact with Mako soon to work it out.

How this will work[edit]

For each debt, we will essentially create a vector of costs that sum to zero with a component for each person. The purchaser will incur a positive value (the amount they are owed for the transaction) while the payees will each pay for either a weighted portion of the negative cost (in the case of general group) or just a portion of the negative cost divided among the payees. On Thursday morning, we will sum up each of the columns for each person and that will be their total debt and the whole thing will sum to zero.

Given the cost of the apartment rental, people who spent more than USD ~$250 on group items are likely to be owed money. Those that spent less will likely owe money. Amost everyone will pay Mika and I who have fronted the rent for the two apartments and are currently USD $4000 in the hole.

There is a little R program that is already written that will handle the debt pool. The software is free software and you're welcome to work on it!

Old Cost Estimates[edit]

These were our "original" plans and projects which basically seem to be holding.


For rent, the current plan is going to be to pool the total cost, split by the number of total person nights, and then charge people by the number of nights they stay. We're basically full. At the current exchange rate, the price will be under USD 20 per person per night.

  • Flat 71: The cost is 1380GBP (~2200USD) from 12/30 through 1/13.
  • Flat 73: The price is 1150GBP (~1780USD) from 1/3 through 1/13.
  • Total: 2530GBP

Additionally, the Guest house will be 25USD/person/night for those who need a place to stay before their houses become available. Guest house payments are being handled totally separately and won't be included in the main bill.


We are planning to cook most of our meals together including dinner each night. We plan to buy all our food in Iceland. BONUS is the local discount supermarket. We will keep receipts and split costs similarly to the way we divide costs for rent (see the section on rent above).

There are at least 4 vegans and a large majority of people attending are vegetarian. The current plan is to cook primarily vegan and exclusively vegetarian to simplify things and to keep costs low.

We're planning on share the cost for vegan items among all people and sharing the costs of explicitly non-vegan items among non-vegans unless the costs are trivially small.

If folks feel a strong desire to cook meat we can try arrange for one kitchen to be meaty.

Folks who don't help cook meals should help clean.