A joint bills account: how much each partner puts in

What goes into a bills-only account?

Every cost you both rely on and that is paid on a schedule, whether it comes monthly or once a year. Say a couple lists nine of them. The table puts each on a monthly footing, so a yearly bill becomes one twelfth of its price.

Bill	Billed	Per month
Rent	Monthly, $1,640	$1,640
Internet	Monthly, $65	$65
Phone plan	Monthly, $95	$95
Electricity and gas	Monthly, average	$175
Water	Monthly, average	$45
Car insurance	Yearly, $1,200	$100
Contents insurance	Yearly, $360	$30
Vehicle registration	Yearly, $540	$45
Pest and gutter service	Yearly, $900	$75
Total	Nine bills	$2,270

The first five add up to $2,020 and the four yearly bills to $250 a month. Groceries, eating out and personal spending stay outside the account, because the account is only for bills.

How much should the account receive each month?

A year of all the bills, divided by 12, then split by each partner’s share. Work it in four steps:

1. Total a year. The monthly bills are $2,020 × 12 = $24,240. The yearly bills are $3,000. Together that is $27,240.
2. Divide by 12. $27,240 ÷ 12 = $2,270 a month.
3. Set the buffer. One month of the variable bills, here the $175 and $45 averages, is $220. It sits in the account as an opening balance.
4. Multiply by each share. Equal or by income, as in the table.

Say one partner takes home $5,500 and the other $4,500, which is 55% and 45% of $10,000.

Partner	Monthly, equal	Monthly, by income	Opening buffer, by income
First partner	$1,135.00	$1,248.50	$121
Second partner	$1,135.00	$1,021.50	$99
Total	$2,270.00	$2,270.00	$220

By income, each partner sends 22.7% of their own take-home pay: $1,248.50 ÷ $5,500 and $1,021.50 ÷ $4,500 are both 0.227. Splitting bills based on income explains the percentage.

When does an annual bill arrive before you have saved for it?

Check the calendar for the first large yearly bill, because dividing by 12 only works after the account has had time to fill. Say the car insurance of $1,200 falls due in month 2. By then the yearly bills have received 2 × $250 = $500, so the account is $700 short.

The fix is a bigger opening deposit: the $220 buffer plus the $700 shortfall is $920. By income that is $506 from the first partner and $414 from the second. After the first full year, the yearly bills fall due on a rhythm and the monthly transfer keeps up.

What if someone pays a bill from a personal account?

Pick one of two routes per bill and write it down. Say the second partner puts the $540 vehicle registration on a personal card.

• Repay from the account. The account sends $540 to the one who paid. The monthly figure stays at $2,270, because the bill was always in the formula.
• Record it as owed. The first partner sends their 55%, which is $297, and the registration comes off the list. The monthly total drops by $45 to $2,225, which is $1,223.75 and $1,001.25 by income.

Repaying from the account is simpler when the bill is already in the formula. Splitting it outside the account makes more sense when the bill was never on the list.

How do you check the account is on track?

Reconcile every quarter by adding up what went in and what came out, then compare the result with the statement. Using the example, the first three months look like this:

• In: the $920 opening deposit plus 3 × $2,270 = $7,730.
• Out: fixed bills of $1,800 × 3 = $5,400, variable bills that came to $205, $160 and $190 ($555 in all), and the $1,200 insurance, with the other yearly bills not yet due. That is $7,155.
• Expected balance: $7,730 minus $7,155 is $575.

If the statement shows something else, look for a bill missing from the list, a bill paid twice or a variable bill that ran above its average. If the balance sits more than a month of variable bills above target for two quarters, lower the transfers, and if it sits below target, raise them.

When is an app simpler than a second account?

Use an app when you have few shared bills, when the amounts swing, or when each of you already pays certain bills from your own account. Say one partner pays the $1,640 rent and the other pays $380 of internet, phone, electricity and water. The equal share of $2,020 is $1,010. The renter is owed $630 and the other owes $630, and one transfer clears it.

In EvenOut, the friend page works as a two-person ledger. Add each bill with the “Paid by” chip set to whoever paid, choose “Equally” or “Percent” for 55 and 45, and set the fixed ones to repeat from “Photo, repeat, pending or note”. “Yearly” is one of the repeat choices, so insurance appears on its due date. On the settle-up day, “Settle up” shows the one balance and records the payment, and EvenOut does not move money.

This page covers the arithmetic only. A joint account’s rules and fees depend on the bank, so read the bank’s terms before you open one.

What should you do next?

List your bills with how often each is billed, run the formula once, and put the monthly figure in a note both of you can see. Joint account versus separate accounts compares how the money moves in each setup, and how to split bills as a couple sets rules for the costs that stay outside the account. The printable couple expense tracker template works for the ones you split by hand.