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Tax year 2026
Fiscal Partner Split Optimiser
Find the split of your mortgage interest, Box 3 income and shared deductions between fiscal partners that costs you the least tax, and see why, before you file or set your provisional assessment.
Private: everything is calculated in your browser. Nothing you enter here is sent to us or stored.
Inputs
Partner APartner B
What you can split
Result
You save with the best split€ 1.722
Compared with putting everything on the higher earner€ 128
Household tax, best split€ 23.743
Household tax, 50/50€ 25.465
The best split
Own home (mortgage interest) for AA 100% · B 0%
Box 3 income for AA 0% · B 100%
Why this split
- The mortgage deduction is worth more to the partner whose income it lowers in a higher bracket, or whose general tax credit it brings back.
- Box 3 income goes where a partner's tax credits would otherwise go unused, but it also counts towards their general tax credit test, so it is not always "all to the lower earner".
- Allowances do not change: they are based on your combined income, which is the same whatever the split.
- Use it in your tax return (the split screen in the partner section), and in your provisional assessment so the monthly refund lands with the right partner.
Partner A: tax with the best split€ 22.286
Taxable wage
€ 82.500
-
Own home
100% × -€ 12.425
€ 12.425
=
Box 1 income
€ 70.075
Box 1 tax and premiums
€ 25.616
-
Tax credits used
general € 534 + labour € 3.282, as far as there is tax to use them against
€ 3.816
+
Own-home deduction capped at the second-bracket rate
€ 486
=
Income tax
€ 22.286
Partner B: tax with the best split€ 1.457
Taxable wage
€ 24.000
=
Box 1 income
€ 24.000
Box 1 tax and premiums
€ 8.580
+
Box 3 tax
36% × € 2.000
€ 720
-
Tax credits used
general € 3.115 + labour € 4.728, as far as there is tax to use them against
€ 7.843
=
Income tax
€ 1.457
Best split against 50/50€ 1.722
Partner A
€ 22.286
+
Partner B
€ 1.457
=
Household tax, best split
€ 23.743
Household tax, everything 50/50
€ 25.465
-
Household tax, best split
€ 23.743
=
You save
€ 1.722
Estimate for two employees below state pension age, both born in 1963 or later (no payout of an unused general tax credit). The search tries every split in 5% steps. The Belastingdienst's own filing software also proposes a split when you file together; use this to understand it and to set your provisional assessment during the year.
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