Practical guide for couples
How to split bills when moving in together
There is no single arrangement that is automatically fair. Compare three common approaches, understand the maths and choose a system you can both explain and revisit.
Start by defining the shared costs
Before choosing percentages, agree which expenses belong in the shared household budget. Rent or mortgage payments, council tax, gas, electricity, water, broadband, groceries and shared insurance are common starting points. Keep personal spending and debts visible, but do not assume they belong in the same calculation.
Use monthly take-home income rather than salary before tax so the comparison reflects the money each person actually receives.
Option 1: an equal 50/50 split
Each person pays half of the agreed shared costs. This is simple to understand and administer. It may work well when incomes, personal commitments and available money are broadly similar.
The drawback is that the same payment can affect two incomes very differently. If one person has much less left after contributing, the arrangement may feel equal on paper but difficult in everyday life.
Option 2: an income-proportional split
Each person contributes according to their share of the combined take-home income.
Worked example
Alex takes home £2,500 a month and Sam takes home £1,500. Their combined income is £4,000, so their income shares are 62.5% and 37.5%. If agreed shared costs are £1,600, Alex contributes £1,000 and Sam contributes £600.
Compare both splits with the free calculatorOption 3: a custom arrangement
A custom split may combine methods. You might share core bills proportionally, split groceries equally and keep personal subscriptions separate. One person might contribute less money during a period of unpaid caring work, study or reduced hours.
Custom does not have to mean complicated. Write down what is shared, how it is divided and when you will review it.
Conversations the calculation cannot settle
- How much personal spending money should each person retain?
- How will unpaid household work and caring responsibilities be recognised?
- Will bonuses, overtime or freelance income be included?
- What happens when an income or bill changes?
- How will joint savings and emergencies be handled?
This is practical information, not financial or legal advice. If your circumstances involve property ownership, legal agreements, debt or financial vulnerability, consider qualified independent advice.
Common questions
Splitting household bills FAQs
Is splitting bills 50/50 fair?
It can be fair when incomes and other commitments are similar, but equal amounts do not always create an equal effect on each person's finances.
How do you calculate an income-proportional split?
Divide each person's take-home income by the combined take-home income, then multiply that percentage by the shared monthly costs.
Which expenses should count as shared bills?
Agree this together. Rent or mortgage costs, council tax, utilities, broadband, groceries and shared insurance are common examples. Personal debts and individual spending are usually discussed separately.
How often should couples review the arrangement?
Review it when income, working hours, caring responsibilities or shared costs change, and at an agreed regular check-in even when nothing feels wrong.