A support calculation can look precise before the underlying questions have been answered. Which rules apply? What income should be used? Which children and expenses are included? What period are you calculating? Resolve those questions first, then use the numbers to inform the discussion.
In this guide
1. Keep three different questions in view
Child support, special or extraordinary expenses and spousal support are related, but each needs its own analysis. A single monthly total can hide different assumptions, obligations and review dates. Ask for the components to be identified separately.
For child support, first identify the applicable federal, provincial or territorial rules. The federal framework discussed here does not settle every situation. In particular, do not assume that selecting the federal Quebec table means the calculator is applying Quebec’s provincial child-support model.
Source: Justice Canada: Child support and the applicable guidelines ↗
Spousal support requires an entitlement analysis before a formula is used. An income difference by itself does not answer every question. The relationship history, roles, economic consequences, needs, means and relevant agreements can matter. The Spousal Support Advisory Guidelines assist with amounts and duration, but are not legislation.
2. Understand the income figure
Income for support is not simply the amount deposited into a bank account each month. Under the Federal Child Support Guidelines, the starting point uses the income sources reported under “Total income” in the tax return, with prescribed adjustments. Other provisions can affect the final figure.
Source: Federal Child Support Guidelines, section 16 ↗
A current salary, last year’s tax return and a three-year income history answer different questions. If earnings fluctuate, explain why. If a person is self-employed or controls a company, more than the amount personally withdrawn may need examination. Flag bonuses, benefits, unusual gains, losses and changes in employment for review.
Label each figure you use: the source, period covered, whether it is gross or net and whether it is confirmed or estimated. Do not quietly substitute an estimate for a missing document.
“The 2025 return shows one figure. The current pay statement shows a different annual rate after a job change in March 2026. I have attached both and need advice on the income to use for the period being reviewed.”
3. Put the table amount in context
Federal table amounts depend on the relevant income, province or territory and number of children. The parenting arrangement and other circumstances can affect the analysis. A table lookup is an important step, but it is not a complete legal assessment of every family’s support obligation.
The 2025 federal tables took effect on October 1, 2025. Earlier periods require the applicable historical tables. The update does not automatically rewrite an existing order. A calculation of what might now be appropriate and a change to an enforceable obligation are different tasks.
Source: Justice Canada: 2025 table update and historical editions ↗
Under section 9 of the federal Guidelines, where each parent exercises at least 40% of parenting time over the year, the assessment considers both table amounts, the increased costs of the arrangement and the circumstances of the parents and child. Subtracting one table amount from the other does not resolve all of those considerations.
Source: Federal Child Support Guidelines, section 9 ↗
Prepare a clear account of the actual parenting arrangement. Adult children, split or mixed arrangements, high incomes and undue-hardship claims can require further analysis. Explain those features before relying on a standard calculation.
4. Examine the expense before dividing it
Not every purchase for a child is an additional section 7 expense. The federal provision identifies categories, including qualifying child care, health, education and extraordinary extracurricular expenses. Necessity and reasonableness matter. Educational and activity expenses can require an assessment of whether they are extraordinary.
The guiding principle is proportional sharing using the relevant incomes, after considering the child’s contribution and the applicable subsidies, benefits and tax relief. Start with the net expense. Do not divide the invoice first and forget reimbursements or tax effects.
Source: Federal Child Support Guidelines, section 7 ↗
Assume an expense qualifies, its verified net annual cost is $3,000, and the applicable income shares are 60% and 40%. The arithmetic gives $1,800 and $1,200 annually. This example does not establish that the expense qualifies or that these are the right income shares for a particular family.
Keep the invoice, proof of payment, reimbursement information and any agreement about the expense together. Record whether the figure is monthly, annual or a one-time amount.
5. Treat a spousal range as part of the analysis
A spousal-support discussion involves entitlement, amount, duration, tax treatment and the way a payment is structured. The right formula depends on the circumstances, including whether child support is being paid. A without-child illustration should not be reused as a with-child calculation.
The with-child formulas involve the treatment of child support, taxes, benefits and disposable income. Those interactions are why a reliable assessment needs more than a percentage of the gross income difference.
Source: SSAG Revised User’s Guide: With-child support formulas ↗
Do not assume that a proposed lump sum is equivalent to multiplying a monthly amount by a number of months. Tax assumptions, timing, discounting, future changes and the agreement’s terms can change the comparison. Obtain legal and tax advice before treating a lump-sum illustration as a settlement value.
6. Gather a useful support file
For federal child-support proceedings, section 21 sets out income disclosure requirements, including three years of tax returns and assessment information, current earnings information and additional documents for business, corporate, partnership or trust interests where applicable. Court rules may require more.
Source: Federal Child Support Guidelines, section 21 ↗
- Tax returns and notices of assessment or reassessment for the three most recent tax years.
- Current pay statements and records of bonuses, benefits or other income.
- Relevant business, corporate, partnership or trust records.
- Children’s details, living arrangements and information about any adult child’s circumstances.
- Expense invoices, receipts, reimbursements and available tax or benefit information.
- Relationship and separation dates, with a note of any uncertainty.
- Existing agreements, orders and records of payments already made.
- The period being assessed and the dates of significant changes.
For spousal support, add a realistic budget and a concise account of the relationship’s work and caregiving arrangements. Describe events and their financial effects rather than simply applying labels.
7. Use the calculators with their scope in view
DivorceNexus offers separate child-support, spousal-support and combined workspaces. They let you explore supported calculations, record assumptions and download reports. The sources and coverage page explains what each module currently does.
The full tax-and-benefit engine and automatic with-child spousal-support ranges remain unfinished. The combined workspace uses a spousal amount entered by the user. That amount is an assumption, not a calculated entitlement or a verified SSAG result. The Quebec provincial model is not available.
Before comparing scenarios, change one assumption at a time and label the reason. A historical table calculation does not, by itself, decide retroactive entitlement or establish arrears under an existing order. A downloaded report records the information and calculations in the workspace. It does not certify the legal correctness of the inputs.
8. Take these questions to the next discussion
- Which law, table edition and calculation period apply?
- What income figure should be used for each person, and what supports it?
- Does the parenting arrangement require a different analysis?
- Which expenses qualify, and have their net costs been checked?
- Is there entitlement to spousal support, and which formula and exceptions need review?
- What changes are needed to the current agreement or order, if any?
- How will updated income, expenses and future reviews be handled?
Bring the records and the report, with estimates clearly marked. If you are exploring a settlement through mediation, an agreed set of financial information can make the discussion more productive. Independent legal advice helps each person understand the proposed outcome before committing to it.
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General Canadian information, not legal, financial or psychological advice or an assessment of your family. Reading this guide or contacting a linked service does not, by itself, create a solicitor-client relationship. Laws and their application vary and change. Sources were checked on the review date, but completeness and continuing accuracy cannot be guaranteed. Obtain advice from a qualified lawyer in the relevant jurisdiction and other professionals where needed.
Examples are illustrative. If you research court decisions, check their later treatment: a decision may have been appealed, overturned or not followed.