Why Alimony Child Support results differ in Brazil
5 min read
Published April 15, 2026 • By DocketMath Team
The top 5 reasons results differ
When you run the DocketMath “alimony-child-support” calculator for Brazil (BR), differences in the output usually come from inputs and jurisdiction-aware rule paths, not from randomness. Below are the top 5 reasons results differ across runs, households, or between people who expect the “same” outcome.
**Who receives support (alimony vs. child support)
- In Brazil, child-related support and spousal support generally follow different logic and are often treated as separate components.
- If one run effectively includes or excludes an alimony component while another run is child support only (or vice versa), the totals won’t match—even when income is the same.
- DocketMath’s model typically distinguishes whether the calculation includes child support, alimony, or both.
Income definition and how “net” is approximated
- Outputs can swing significantly depending on whether the calculator treats the entered figure as gross income or an approximated net income after deductions.
- Common sources of mismatch include:
- using gross in one run and net in another,
- approximating deductions/withholdings differently,
- or changing how irregular earnings are represented (even indirectly).
Number of children and allocation
- Brazil-focused child support calculations are sensitive to child count because the model may allocate amounts on a per-child (or scaled) basis.
- Result: even if the same income is used, the breakdown can change when you change the number of children entered.
**Custody/guardianship reality captured (or omitted)
- In practice, day-to-day custody arrangements and who bears most child-related costs can affect the support outcome.
- If you enter custody-related flags inconsistently—or leave them blank in one run but not in another—DocketMath may route to different jurisdiction-aware rule outcomes.
Rule switches for scenario type and effective date
- The calculator may route through different settings depending on scenario type, such as:
- initial determination vs. modification,
- combined vs. separated components.
- Example mismatch: comparing a run that includes child support + alimony to a run that includes child support only. The numbers can be “correct” for each scenario but still differ from each other.
Common pitfall: Even when you type the same “monthly income” twice, the result can still differ if one run includes assumptions like deductions/allowances differently. The key is aligning the meaning of each input, not just the numeric value.
How to isolate the variable
To pinpoint why your DocketMath results differ, use a controlled, step-by-step approach. The goal is to change one factor at a time while everything else stays fixed.
Lock the scenario
- Pick one clear setup and keep it constant across reruns (for example: child support only vs alimony + child support).
- If the tool has toggles, confirm they remain the same across runs.
Hold all income fields constant
- Copy the same income figure into every income-related input.
- Also record what that figure represents:
- gross salary, or
- net after standard deductions, or
- net after custom/entered deductions.
- If your “net” assumptions differ between runs, the outputs may differ even if the number is identical.
Change only one input at a time Use a small test sequence:
- Run A: baseline (everything identical)
- Run B: change only child count
- Run C: change only custody/guardianship-related flag(s)
- Run D: change only the income definition (gross vs net)
After each run, note:
- the delta (how much the output changes),
- and which component moved (child support component vs alimony component).
Compare the breakdown components, not only the final total
- If DocketMath shows a component breakdown (for example, child support vs alimony), compare component-by-component.
- This quickly reveals whether the difference is coming from an included/excluded component or from an assumption affecting the underlying calculation.
If you want a consistent starting point, open the tool here: /tools/alimony-child-support.
For other DocketMath workflows, you may also find these helpful: /tools.
Next steps
Once you identify the input or rule path that changes the outcome, you can move from “why doesn’t it match?” to “which assumption is driving the difference?”
Step 1: Create a “most defensible” input set
- Use documented pay figures where possible.
- Keep the income definition consistent across runs (gross vs net) so comparisons are meaningful.
Step 2: Produce two labeled outputs
- Label them clearly to prevent accidental comparisons of different scenario paths, such as:
- “Scenario 1: child support only”
- “Scenario 2: child support + alimony”
Step 3: Re-run with a single changed assumption
- If custody-related reality is the suspected driver, adjust only those custody flags and re-check the breakdown.
Step 4: Maintain a short change log
- Record:
- what you changed,
- the timestamp (if relevant),
- and the output difference after each change.
Gentle note: DocketMath is designed to model how inputs map to outputs, but it isn’t a substitute for legal review of the actual case facts and documents.