A fair contribution cannot be judged by the number alone.
Couples can spend a long time trying to find the fairest percentage, whether that is fifty-fifty because it feels equal or a proportionate split because it feels more considered. Then one person earns more, one takes parental leave, the household takes on a larger mortgage, or a career changes, and the neat percentage starts carrying more than arithmetic can settle.
The calculation shows how the costs are split, but it doesn’t indicate what those costs imply for either person.
The arithmetic cannot settle fairness
Imagine one person earns roughly twice what the other earns. They split their household costs equally because neither wants to feel they are being carried by the other. The arrangement is simple, and it may even feel reassuringly neutral. But the same contribution can leave one person with plenty of capacity to save, make personal choices and absorb an unexpected expense, while leaving the other with very little.
So they move to a percentage split. Perhaps the higher earner contributes two-thirds and the lower earner one-third. The numbers now reflect their incomes more closely, but the calculation still can’t see everything. It cannot tell you how the household came to cost what it does, whether the income difference has always existed, whether choices made for the relationship helped create that difference, or what financial life remains for either person once the shared costs have been paid.
A percentage can split a bill, but it cannot determine what two people owe for the life they share.
Whose life set the cost?
Before deciding how to divide the cost of a shared life, it is worth asking how that cost came to be there.
I wrote in How Much Does the Life You Want Cost? about describing the life before deciding what it takes to fund it. There is a version of that question for couples. Two people can agree on a contribution formula without ever examining who had more influence over the lifestyle the formula pays for.
One income may have made a larger mortgage comfortable, or one person’s work may have brought expectations about where the family would live or how often they would travel. Both people may well have wanted those choices at the time. The point is not to reopen every household decision looking for someone to blame, but to recognise that a shared lifestyle can grow around the income with the greatest capacity to fund it.
That works well until the cost of maintaining that life begins to mean something different for each person. Someone can enjoy the home they live in and still have little left after paying their share, even while living a life their own income could not have funded.
Look at what the arrangement leaves behind
Once the shared life has been funded, look at the financial lives that remain.
One person does not need to have the same amount left as the other. But if one partner is steadily building savings and the ability to make choices while the other uses almost everything available to meet their share of the household, that deserves attention. So does an arrangement in which one person can absorb an unexpected expense without discussion while the other must ask, or one in which both names appear on the household finances while only one person has any meaningful financial capacity of their own.
This connects with what I wrote in Joint Accounts Are Not the Same as Financial Partnership. Shared responsibility doesn’t require identical financial roles, and fairness doesn’t require identical contributions either. What matters is what the arrangement is doing to both people over time.
The payslips may not tell the whole story
There is one more thing the income figures cannot show, and it is why I would hesitate to let them decide the question on their own.
Income does not always arrive untouched by the relationship around it. One person may work fewer hours because they do more of the childcare. A promotion involving heavy travel may have been turned down because it did not suit family life. One career may have moved more slowly after a relocation made for the other’s work. There may have been parental leave, a period away from paid employment, or years in which one person’s greater availability at home made the other’s progression easier.
If one person’s earning capacity has been shaped by decisions made for the shared life, payslips do not tell the whole story of what each person contributes.
The person earning more may have worked extremely hard to build that income. The person earning less may also have made choices that helped the household function in a way that made the higher income possible. Both can be true without turning the relationship into an exercise in calculating who sacrificed more. The useful question is whether the financial arrangement recognises the life that produced the numbers now being divided.
Fair may need to change
An arrangement can make sense for years and still stop fitting the life around it. Parental leave ends, salaries rise, and caring responsibilities appear where there were none. The arrangement that made sense five years ago can stay in place long after the circumstances that shaped it have gone.
The original agreement may have been right at the time; the facts underneath it have since moved, and a percentage set against the old facts is worth revisiting.
If you are trying to decide whether your current arrangement is fair, take the percentages off the table for a moment. Talk about the life you are funding and how its cost was set, about whether decisions made for your relationship have affected either person’s earning position, and about what the arrangement leaves each of you able to build, choose and withstand. Then put the numbers back.
You may arrive at the same split. But this time you will know what the percentage is being asked to carry.
If one person cannot access household money, is prevented from working, or feels unsafe raising these questions, this goes beyond a discussion about fairness. Specialist support is available from organisations such as Surviving Economic Abuse.
Work out what fair means for the two of you
The Couples Money Conversation Guide helps you talk about the financial life you share, including responsibility, priorities and the decisions that need both of you in the room.
Author
Grace Ogunjobi, FCCA, is a finance counsellor and author with more than 30 years’ experience in finance.
