Calculate fair bill splits proportional to income. Perfect for couples and roommates with different salaries.
Enter salaries to see the recommended split percentages
When roommates or partners share expenses but earn different amounts, splitting everything 50/50 can feel unfair. An income-based split solves this by making each person’s share proportional to what they earn.
The concept is simple: people with higher incomes pay a larger share, while those earning less contribute proportionally less. This approach works for any shared expense where both parties benefit equally—rent, utilities, groceries, streaming subscriptions, or vacation costs.
The math behind income-based splitting is straightforward. Your share is determined by comparing your income to the total household income.
First, you add up everyone’s income to get the combined total. Then, you divide each person’s income by that total to find their percentage. That percentage becomes their share of every bill.
$2,000
$2,000
Fair Share Calculation:
Person A: $2,000 ÷ $5,000 = 40% of bills
Person B: $3,000 ÷ $5,000 = 60% of bills
Follow these three steps to calculate income-based splits for any shared expense:
Sum everyone's monthly or annual income to get the combined total.
Divide each person's income by the combined total, then multiply by 100.
Multiply any shared bill by each person's percentage to find what they owe.
• Person A pays: $300 × 40% = $120
• Person B pays: $300 × 60% = $180
Total covered: $120 + $180 = $300 ✓
When one person earns substantially more than the other, income-based splitting prevents financial strain on the lower earner.
Roommates or partners sharing a home benefit from this consistent, fair approach month after month.
Partners at different career stages can maintain equity without one person feeling financially burdened.
Works best when everyone uses and benefits from the space equally, regardless of who pays more.
Some people prefer keeping salary information private, especially with roommates they don’t know well. An equal split avoids sharing financial details.
If one person uses far more of something (like electricity for a home office), a usage-based split makes more sense than income-based.
For occasional dinners out or splitting a taxi, equal splitting is simpler and faster. Save income-based for recurring bills.
Decide upfront whether you're using pre-tax (gross) or take-home (net) income. Mixing the two creates an unfair comparison. Most people find take-home pay more accurate since it reflects actual spending power.
If someone receives annual bonuses or commission, include these in the calculation. Average them over 12 months to get a more accurate monthly income figure.
Only split truly shared expenses proportionally. Personal items like individual phone bills or gym memberships should remain separate, even if you're splitting rent.
When someone gets a raise, loses a job, or changes careers, recalculate the percentages. Stale ratios defeat the purpose of income-based fairness.
Everyone pays the same amount regardless of income.
✓ Simple and fast to calculate
✓ No need to share income details
✓ Works well for similar earners
✗ Can feel unfair with income gaps
Payment proportional to what each person earns.
✓ Fair based on financial capacity
✓ Reduces money-related tension
✓ Best for significant income differences
✗ Requires sharing income information
💡 Pro Tip
Whichever method you choose, commit to it for at least a full month. Switching back and forth creates confusion and makes tracking expenses harder. Set a monthly review date if you want to reassess, but stay consistent between reviews.
Calculate splits in USD, EUR, GBP, CAD, or AUD
Split several expenses at once with automatic totals
Export percentages to clipboard instantly
Add as many people as needed (2 minimum)
See each person's share with color-coded graphs
See total amounts owed across all bills
Total = Sum of All Incomes
Adds everyone’s salary to establish the baseline for calculations
Share % = (Your Income ÷ Total Income) × 100
Determines what percentage of bills each person should pay
Your Amount = Bill Total × (Your Share % ÷ 100)
Applies your percentage to any specific bill amount
Three people share an apartment with multiple monthly expenses. Here’s how income-based splitting works across different salaries and bills:
Roommate A
$2,000
monthly income
Roommate B
$3,000
monthly income
Roommate C
$5,000
monthly income
1. Combined income: $2,000 + $3,000 + $5,000 = $10,000
2. Calculate percentages:
• A: ($2,000 ÷ $10,000) × 100 = 20%
• B: ($3,000 ÷ $10,000) × 100 = 30%
• C: ($5,000 ÷ $10,000) × 100 = 50%
3. Apply to $900 rent:
• A pays: $900 × 20% = $180
• B pays: $900 × 30% = $270
• C pays: $900 × 50% = $450
✓ Verification: $180 + $270 + $450 = $900
Important: Notice how Roommate A (lowest earner) pays the least while still contributing fairly. Meanwhile, Roommate C (highest earner) covers half the rent, which aligns with earning half the household income.
Rent: $900
A: $180 | B: $270 | C: $450
Utilities: $150
A: $30 | B: $45 | C: $75
Internet: $60
A: $12 | B: $18 | C: $30
Total Monthly Amounts:
Roommate A: $222 total (20% of $1,110)
Roommate B: $333 total (30% of $1,110)
Roommate C: $555 total (50% of $1,110)
Percentage Sum Validation
All share percentages must add up to exactly 100%. This guarantees the full bill is covered—no more, no less.
Zero Income Handling
If someone has no income, the calculator redistributes percentages among earners. (Though in practice, you may want to discuss if non-earners should contribute a fixed amount.)
Consistent Proportions
Once calculated, percentages remain constant across all bills. Whether it’s $100 or $1,000, everyone pays their fair share.
Once you've set the percentages, use Bill Split Pro to track shared bills and settle up cleanly over time.