Stop Retyping the Same Split Every Time

A lot of shared expenses don't get split evenly, and the people splitting them have usually thought carefully about why. One person earns more. One has the bigger bedroom. One drives the car every day while the other takes the train. The agreement gets made once, and it holds.

The trouble starts after that. Most expense apps treat an even split as the default and anything else as an override, so a 60/40 household re-enters 60/40 several times a week. It only takes a few seconds, but it's a decision you have to make on every single expense, and after a couple of months people stop making it.

Not Everyone Splits Down the Middle

Even splitting is the right answer for most groups. Four friends at dinner, four equal shares, done. It stops being the right answer when the people sharing costs have meaningfully different incomes, different amounts of space, or different amounts of use.

Three arrangements come up over and over:

• Income-proportional: One person earns $72,000 and the other $48,000. An even split of a $2,400 rent means the lower earner spends 30% of their gross pay on housing while the higher earner spends 20%, so a lot of couples land on 60/40 instead.
• Space-proportional: In a three-bedroom apartment where one room is nearly twice the size of the others and has the only private bathroom, 40/30/30 on rent is far more common than three equal thirds.
• Usage-proportional: Car insurance, a parking space, a family phone plan where one line uses most of the data. Whoever uses more pays more.

Plenty of households run more than one of these at the same time. Rent by room size, utilities by income, groceries down the middle. What they all have in common is that the percentages were decided deliberately and are expected to keep applying.

How to Decide on a Fair Split

If you're setting this up for the first time, four approaches cover almost every case. Each one is defensible, and each one has a cost.

Even Shares

The default for good reasons. It requires no disclosure of income, no arithmetic, and no renegotiation. It's the right call when incomes are close, when the group is temporary, or when the amounts are small enough that precision costs more than it's worth. It gets uncomfortable when incomes diverge, because the same dollar amount is a very different sacrifice at $48,000 than at $72,000.

Proportional to Income

Each person pays the share of the bill that matches their share of the combined income. With $72,000 and $48,000, that's 60/40. It's easy to explain, and it tracks what most people mean when they say fair.

The costs are real. You have to tell each other what you earn, you have to agree on gross or net (net is usually the better basis, since it accounts for tax and mandatory deductions), and you have to revisit it whenever someone's income changes. Variable income from freelancing, commission, or tips makes it harder still; the common fix is a trailing twelve-month average, reviewed once a year. We go through this in more detail in our guide to splitting expenses as a couple.

Proportional to Use

Rent by square footage, a car by who drives it, utilities by who is home during the day. This works well when use is easy to observe and reasonably stable, which is why it's the standard approach for rent and shared household bills. It's a poor fit for groceries or a shared streaming subscription, where measuring use accurately costs more effort than the difference is worth.

Equal Leftover

Each person contributes enough that both are left with the same discretionary amount once the essentials are paid. This handles the situations income ratios miss, like student loan payments, child support, or supporting a parent. It's the most equitable of the four and by far the most work, because it requires sharing obligations rather than just income, and recomputing whenever any of them change.

Whichever you pick, write the percentages down along with the reasoning, somewhere both of you can find it. The specific numbers matter less than both people being able to explain them a year from now. A split nobody can reconstruct is a split that gets quietly abandoned.

The Problem With Re-Entering It Every Time

Agreeing on 60/40 takes one conversation. Applying it takes the rest of the year.

In most apps, a new expense opens on an even split. To make it 60/40 you switch the split mode, type 60, type 40, check that it adds to 100, and save. Call it ten seconds. A household with six shared expenses a week does that roughly 300 times a year.

The time isn't really the problem. Three other things are.

• Small amounts get skipped: On a $14 coffee run, the difference between even and 60/40 is $1.40, so you take the default. Those decisions are individually reasonable and collectively wrong.
• Only one person maintains it: Whoever pushed for the arrangement remembers to apply it. Anyone else who logs an expense gets the default, so the ledger becomes a mix of two different agreements.
• Typos survive: A 65/35 entered by mistake looks exactly like every other line in the list. Nobody reconciles a shared ledger expense by expense, so it stays.

The end state is a ledger that no longer matches what you agreed to. No single expense is wrong by much, which is exactly what makes the drift hard to notice and awkward to raise six months later.

This is a solved problem, and it's worth being clear about how it's usually solved. Splitwise supports saved default splits, and lists "Default split settings" among the features that require Splitwise Pro, alongside receipt scanning, currency conversion, and unlimited expenses. Splitwise doesn't publish a price for Pro on its marketing pages; the tiers appear on the upgrade screen. As of August 2026 an individual plan billed annually is $59.99 per year, and paying month to month is $7.99 (pricing varies by region). For households that split evenly, none of that matters. For a household whose normal case is uneven, it means the alternative to subscribing is re-entering the same percentages indefinitely. We covered what the free tier does and doesn't include in our Splitwise free vs Pro breakdown

Saving the Split Once

We build SplitterUp, so weigh this accordingly. Since version 1.27.0, groups and partners can save the percentages they actually split by, and every new expense there starts with those percentages already filled in. You set it in Group Settings for a group, or on the person's profile in the Friends tab for a partner.

A few details matter more than the headline:

• One category can differ: Electricity can be 40/30/30 while internet stays even, without breaking the rest of the arrangement.
• Even is a choice: You can deliberately save an even split, which is a different thing from never having set one. The distinction is what tells the next person that the arrangement was decided rather than defaulted.
• Everyone can see it: Each person can see the split that applies to them. Admins change it for a group, and either person can change it for a partner split.
• Membership changes aren't guessed at: If someone joins or leaves, the saved split no longer matches the group, so expenses go back to splitting evenly and the app tells you. It will never invent new percentages on your behalf.

That last one carries more weight than it looks like it does. A saved split that quietly redistributes a departed roommate's 30% across whoever is left is worse than no saved split at all, because it produces a plausible number that nobody checks.

The same release made settling up more forgiving, which comes up constantly in uneven households for an obvious reason: when one person owes 60% of everything, they're more likely to pay it back in pieces. You can now record part of what someone paid you instead of the whole balance, and either person can remove a payment that was recorded by mistake. The debt reopens, the other person is told, and the removal stays visible in the history rather than disappearing.

If you and your partner want to act as a single unit against the rest of a group while still tracking what you owe each other, Households handles that layer separately. SplitterUp is free for a limited time. Create your account now and you keep Premium permanently; join later and it's a one-time $4.99.

When the Split Should Change

A percentage split is a snapshot of a situation, and situations move. The changes worth reopening the conversation for are usually these:

• A raise or a job change: A 60/40 based on $72,000 and $48,000 is no longer 60/40 once the lower earner moves to $60,000.
• A move: New apartment, new room sizes, new relative value. Any space-based split has to be redone.
• A change in hours: Someone going part-time, taking a sabbatical, or going back to school.
• A new dependent: A baby, or a parent who needs support, changes what each person has left over even if incomes haven't moved.
• A large new obligation: Student loans entering repayment, a car loan, or medical costs.

Set a review date rather than waiting for the subject to raise itself. Once a year, or any time one person's income moves by more than about 10%, is a reasonable rule. Renegotiating on a schedule is much easier than renegotiating because someone has been quietly unhappy for four months.

When the numbers do change, update the saved split and new expenses pick it up from there. Decide explicitly whether the change takes effect today or from the start of the month, and say which, because that's the part people remember differently later.

For expenses already recorded under the old percentages, edit their splits rather than deleting and re-entering them. Deleting throws away the receipt, the date, the notes, and any payments already recorded against that expense, and it moves other people's balances in ways they didn't ask for. Adjusting the shares on the existing expense leaves the record intact and changes only the amounts.

If you're choosing an app for reasons beyond default splits, our roundup of the best expense splitting apps weighs pricing, receipt scanning, and split customization across seven options.

Frequently Asked Questions

What's a fair way to split expenses when one person earns more?

The most common approach is to split in proportion to income. If one person earns $72,000 and the other earns $48,000, that's a 60/40 split. Net income is usually a better basis than gross, since it accounts for tax and mandatory deductions. The alternative is an equal-leftover split, where each person pays enough that both are left with the same discretionary amount once the essentials are covered.

Does Splitwise let you save a default split?

Yes, but it requires a paid plan. Splitwise lists default split settings among the features included in Splitwise Pro. Free accounts can still split unevenly on any individual expense; they just have to enter the percentages each time.

How should roommates split rent when the bedrooms are different sizes?

The usual method is to weight rent by room size, either by measured square footage or by an agreement about which rooms are worth more. In a three-bedroom where one room is much larger and has a private bathroom, 40/30/30 is a common arrangement. Shared space is normally counted as equal, and only the private rooms are weighted.

What happens to a saved split when someone joins or leaves the group?

In SplitterUp, a saved split that no longer matches the group's members stops being applied. New expenses go back to splitting evenly and the app tells you the saved split is no longer in effect. It does not redistribute the missing person's share on its own, so someone has to set the new percentages deliberately.

Can you change how a past expense was split without deleting it?

Yes. In SplitterUp you can edit an expense's split after the fact, which adjusts each person's share on the existing record. That's better than deleting and re-entering, because deleting discards the receipt, the notes, and any payments already recorded against that expense.