Tax and budget · Budget and housing
Couple’s budget in 2026: how much should each partner pay?
Updated on
Since 1 November 2026, withholding tax on pay has been calculated differently (Royal Decree of 27 September 2026). The calculations on this page still follow the previous rules: for pay received from 1 November, withholding tax and net pay may differ. Update in progress.
With €3,500 and €2,500 gross a month, two white-collar workers receive about €2,672 and €2,391 net on average over the year: out of €2,000 of shared expenses, splitting in proportion to income gives €1,056 for one and €944 for the other. Each partner thus keeps the same share of their net pay. If one of them switches to four-fifths, it is the lower earner who costs the household the least (€318 a month against €367).
The tool calculates each partner’s net pay with the Indexo engine (holiday pay and bonus included), adds your joint loans and simulates a separation: children’s residence and maintenance payments. Parameters as of 1 October 2026.
Calculate your budget as a couple
Enter your two gross salaries, your status and your shared expenses. Indexo calculates each partner’s net pay, each partner’s pro rata share, and what switching to part-time or a separation would change. Nothing is sent: everything is calculated in your browser.
The tool could not be displayed. Reload the page (Cmd + Shift + R on a Mac, Ctrl + F5 on a PC).
Fifty-fifty or in proportion to income?
Splitting equally seems simple, but weighs more heavily on the lower earner. Pro rata, each pays the same share of their net pay: both keep the same proportion for themselves.
| Gross salaries | Net of one partner | Net of the other | Pro rata: one partner | Pro rata: the other | Fifty-fifty: each |
|---|---|---|---|---|---|
| €2,500 and €2,500 | €2,391 | €2,391 | €1,000 | €1,000 | €1,000 |
| €3,500 and €2,500 | €2,672 | €2,391 | €1,056 | €944 | €1,000 |
| €4,000 and €2,000 | €2,925 | €2,140 | €1,155 | €845 | €1,000 |
| €5,000 and €2,500 | €3,405 | €2,391 | €1,175 | €825 | €1,000 |
| €3,000 and no salary | €2,507 | €0 | €2,000 | €0 | €1,000 |
Joint loans (mortgage, car) are added to the expenses: the tool splits them the same way. Your full living budget: the salary you need.
If one of you switches to four-fifths, who loses the least?
Gross pay falls by a fifth, but net pay falls less: withholding tax (bedrijfsvoorheffing / précompte professionnel) falls, and the work bonus (werkbonus / bonus à l’emploi) can increase for lower salaries. The loss is therefore not the same for both.
| Gross salaries | The first switches to four-fifths | The second switches to four-fifths | The least costly |
|---|---|---|---|
| €2,500 and €2,500 | €318 | €318 | The same |
| €3,500 and €2,500 | €367 | €318 | The second (€2,500) |
| €4,000 and €2,000 | €404 | €380 | The second (€2,000) |
| €5,000 and €2,500 | €480 | €318 | The second (€2,500) |
With parental leave or time credit, an NEO allowance reduces the loss further: see switch to four-fifths and leave and career breaks.
Married, legal or de facto cohabitants
The couple’s status changes the tax: married couples and legal cohabitants file a joint tax return, with the marital quotient when one earns little. To compare the two statuses: marriage or cohabitation, what changes. Here, we start from your status to split the budget.
In the event of separation
- Each becomes single again for tax purposes, with their own net pay and their own costs.
- Shared custody of the children: if a registered or court-approved agreement, or a judgment, provides for it, each parent receives half of the supplement to the tax-free amount for dependent children (for two children: €2,565 each out of €5,130), and each parent taxed as single also receives, in full, the single-parent supplement (€2,030).
- Maintenance payments: in 2026, 60% of the maintenance paid is deductible for the payer, and 60% is taxable for the recipient (50% from 1 January 2027; 80% until 2024). When paid for children, it is declared in each child’s name.
- No double benefit: you cannot deduct maintenance payments for a child you claim as a dependant for tax purposes.
Example: with €3,500 and €2,500 gross and two children in shared custody, the tax benefit for the children is worth about €1,464 a year for each parent. For support linked to the new situation: support you may be entitled to.
Indicative information. A separation also affects housing, family allowances and property: a notary, a lawyer or an approved family mediator will advise you.
Frequently asked questions
How should a couple share expenses?
In proportion to net income: each pays the same share of their net pay. With €2,672 and €2,391 net, out of €2,000 of expenses, one pays €1,056 and the other €944. Splitting fifty-fifty weighs more heavily on the lower earner.
Who should switch to four-fifths to lose the least?
Usually the lower earner, since a fifth of their salary is fewer euros; withholding tax and the work bonus absorb part of the drop. The tool compares both cases with your salaries.
Are maintenance payments deductible in 2026?
Yes, at 60% for payments made in 2026 (80% until 2024, 70% in 2025, 50% from 2027), if they arise from a legal obligation and are paid to someone outside your household. They are taxable in the same proportion for the recipient.
How are the tax benefits for children shared in shared custody?
In shared custody set out in a registered or court-approved agreement, or in a judgment, the supplements for children are split half and half between the two parents, and each parent, if taxed as single, receives the single-parent supplement. Otherwise, the supplements go to the parent with whom the children are registered as living.
What next?
- Marriage or cohabitationWhat the couple’s status changes for tax.
- Switch to four-fifthsThe real loss in net pay, with or without an allowance.
- How much can we borrow?Your two net incomes, the monthly repayment and the purchase price.
- Benefits you may be missingSupport your household may be entitled to.
Sources
Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.
- Modifications du traitement fiscal des rentes alimentaires, FPS Finance, circular 2026/C/12 (as reproduced by Forum for the Future, 7 January 2026) (secondary source).
- Réforme de l’IPP votée : ce que cela change pour votre salaire, vos enfants, votre couple (12 July 2026), Forum for the Future (Deg & Partners) (secondary source).
- Régime de la coparentalité fiscale (article 132bis du CIR 92), FPS Finance, circular 2022/C/63 (as reproduced by Forum for the Future, 30 June 2022) (secondary source).
- Supplément de quotité exemptée pour le contribuable isolé avec enfants à charge, Article 133, first paragraph, 1°, of the Income Tax Code 1992 (text reproduced by lex.be) (secondary source).
- Je suis séparée : qui peut déclarer les enfants à charge fiscalement ? (20 April 2026), Droits Quotidiens (secondary source).
- Cadre VI : rentes alimentaires perçues (18 May 2026), Billy (tax guide) (secondary source).
- Calcul du précompte professionnel : annexe III de l’AR/CIR 92 et formule-clé 2026, FPS Finance.
- Instructions administratives : le bonus à l’emploi, NSSO.
- Pécule de vacances : base de la cotisation sur le double pécule, NSSO.
- Annexe III : précompte sur le pécule de vacances et les allocations exceptionnelles 2026, FPS Finance. Cross-checked with: Securex.
- Loi du 15 juillet 2026 portant réforme de l’impôt des personnes physiques, published on 29 July 2026, Belgian Official Gazette. Cross-checked with: Attentia and Wolters Kluwer.