Last updated: July 2026
by Jess Knauf, Director of Client Strategy. Fact-checked by Belinda Atkins, Managing Director, Family Legal Ltd. Information reflects current family law and mediation requirements in England and Wales as of 31st July 2026.
Self-employed income rarely fits neatly into a single annual figure.
Key Takeaways
- The Child Maintenance Service uses the taxable profit shown on your Self Assessment return, which it takes straight from HMRC, not your turnover or your drawings.
- For a company director, the figure is usually salary plus dividends, so profit left inside the company is not counted in the standard calculation.
- Self-employed income changes are harder to reflect mid-year, because the CMS normally needs a newer tax return before it will revisit the figure.
- A receiving parent can apply for a variation where there is unearned income of £2,500 a year or more, non-earning assets each worth over £31,250, or income being diverted.
- Mediation lets London parents build in averaging, review dates and extras such as nursery fees, which a standard calculation cannot do.
SELF-EMPLOYED CHILD MAINTENANCE
Self-employed child maintenance is worked out on the paying parent’s gross taxable profit as reported to HMRC, then run through the same percentage rates used for employed parents. Because that profit can move sharply from one year to the next, many freelancers, contractors and directors find the resulting figure either too high or too low for the year they are actually in. Agreeing your own arrangement in mediation, with a review point built in, usually fits self-employed income far better.
Working out self-employed child maintenance is rarely as tidy as the online calculator makes it look, and if you are a freelancer, contractor or company director in London you have probably already found that out. There is no payslip to point at. Your income last year may bear very little relation to your income this year, and the figure the Child Maintenance Service lands on can feel disconnected from what is actually in your business account.
For the other parent, the picture looks different again. Not knowing what your ex genuinely earns is unsettling, particularly when London rent or nursery fees have to be paid on the first of the month regardless. Money and children together make this one of the trickier family disputes we see, and it is one where a conversation almost always beats a battle.
How Does the CMS Work Out Self-Employed Child Maintenance?
The formula itself is the same one everyone gets. What changes is where the income figure comes from. For an employee it arrives from payroll data. For a self-employed parent, the CMS takes the gross taxable profit declared on the most recent Self Assessment return, supplied directly by HMRC, and converts it to a weekly amount.
- Sole traders and partners: net profit after allowable business expenses, not turnover and not what you drew out
- Company directors: usually salary plus dividends, so profit retained in the company sits outside the standard calculation
- Pension contributions: personal and occupational pension payments come off before the rates are applied
- No return filed yet: the CMS may use business figures you provide, or apply a default rate of £38 a week for one child, £51 for two and £64 for three or more
Once the gross weekly figure is set, the basic rate takes 12% of income between £200 and £800 a week for one child, 16% for two and 19% for three or more, with lower percentages applied to the slice between £800.01 and £3,000. Shared care reduces it further, starting at one seventh once the children stay with the paying parent at least 52 nights a year. Anything above £3,000 gross a week is outside the CMS formula altogether, and the receiving parent has to ask the court for a top-up order. The full method is set out in the GOV.UK guide to how child maintenance is worked out (figures as of July 2026), and you can sense check a figure with the official child maintenance calculator.
Is Self-Employed Child Maintenance Harder to Agree in London?
London has an unusually large freelance and contractor population: creative and media work around Shoreditch and Soho, IT and finance contracting in the City and Canary Wharf, construction and trades across every borough, and a long tail of consultants, therapists and tutors working from a spare room in Zone 3. Very few of those people earn the same amount two years running.
That creates three recurring flashpoints. The first is timing. A parent whose day rate collapsed in April is still assessed on a bumper year that ended in the previous tax year. The second is visibility. Retained profit, a director’s loan account and a modest salary can all be perfectly legitimate, and can still look to the other parent like money being hidden. The third is cost. London childcare and housing leave very little slack, so a figure that is out by £150 a month genuinely matters to both households.
There is also a rule difference that catches people out. An employed parent whose income moves by at least 25% can ask for the calculation to be revisited. For a self-employed parent, a change outside the annual review generally needs evidence of a newer tax return already submitted to HMRC, which can mean waiting until the tax year has closed. If your income has just dropped, that wait is painful. We covered the wider picture in our guide to the latest changes to child maintenance rules, and there is neutral background on the whole system at childmaintenance.org.uk.
Can a Receiving Parent Challenge a Self-Employed Ex’s Income?
Yes, and it is worth knowing this before assuming the tax return is the end of the matter. A receiving parent can apply for what is called a variation, which asks the CMS to look beyond the standard figure. The main grounds are:
- Unearned income: taxable income of £2,500 a year or more from rent, dividends, savings or investments
- Notional income from assets: assets each worth more than £31,250 that produce no income, with a return then assumed on them
- Diversion of income: where a parent controls how much income they receive, for example by leaving profit in a company or routing pay elsewhere
The Department for Work and Pensions also has a Financial Investigations Unit for more complex cases, which can cross check records with HMRC. The House of Commons Library briefing on child maintenance variations explains the grounds in detail. What it cannot tell you is how long the process takes or what it does to a co-parenting relationship, and that is where many London parents decide to try something else first.
“We see a lot of London contractors and company directors who are not hiding anything at all, they simply have income that moves. The argument is usually about uncertainty rather than dishonesty. Once both parents can see the same accounts on the same screen, agreement comes quickly, and the agreement they build tends to survive the next bad quarter far better than an imposed figure does.”
Jess Knauf, Director of Client Strategy
Self-employed and stuck on a maintenance figure?
Start with a MIAM, the first meeting where a mediator explains your options in private. It is free if you qualify for legal aid, and many child arrangements cases also attract the £500 family mediation voucher.
How Can Mediation Help Self-Employed Parents Reach a Fair Agreement?
The CMS applies one formula to one figure. Mediation lets you design something that actually fits how a business earns money. In our experience of financial mediation with London families, the arrangements that hold up over time tend to share a few features.
- Averaging: using profit averaged over two or three years rather than a single strong or weak year
- A floor and a ceiling: a minimum monthly payment that holds in a quiet month, plus a percentage share of profit above an agreed level
- A review date: usually pegged to the filing of the next tax return, so nobody has to ask awkwardly
- Extras named separately: nursery fees, school trips, music lessons, kit and travel, which the CMS calculation does not cover
- Payment timing: allowing for January and July payments on account, which flatten a self-employed parent’s cash flow
Openness is what makes this work. Both parents share the same documents, and the mediator keeps the conversation on the numbers rather than on old grievances. If you want to get ahead of that, the free financial disclosure checklist generator lists what to gather before the first session.
Could you get legal aid or the £500 voucher?
London Mediation Service is a Legal Aid Agency contracted provider for family mediation, so legal aid mediation is available through our service where you qualify (it is means-tested, and self-employed income is assessed on your accounts). Your MIAM is free if you qualify for legal aid. Many child-arrangements cases also qualify for the £500 family mediation voucher, which is not means-tested. You can check your legal aid eligibility in a couple of minutes.
A Clerkenwell contractor and a Walthamstow teacher agree a formula in two sessions
He contracted through his own limited company and had just come off a long project. Her CMS figure was based on his best year in a decade and she could not understand why he said he could not pay it. In mediation they looked at three years of accounts together, agreed a monthly base figure they both felt was survivable, added a share of profit above a set threshold paid each January, and set a review for the week after his accountant files. Details changed to protect confidentiality.
Is a Mediated Child Maintenance Agreement Legally Binding?
Not on its own. What you agree in mediation is written up in a memorandum of understanding, a plain English summary of your decisions. Many parents run their arrangement on that basis and it works perfectly well, particularly where payments are made by standing order.
If you are also sorting out the wider finances of a divorce, the child maintenance figure can be recorded in a consent order, the document a judge approves to make a financial settlement binding. One point to hold on to: under the Child Support Act 1991, a child maintenance clause in a court order only keeps the CMS out for 12 months from the date of the order, after which either parent can apply for an assessment. School fees and top-up maintenance for very high earners stay with the court. Our guide to agreeing finances after divorce sets out how the two fit together.
Family Law Service
Ready to make your financial agreement official?
If you have reached agreement on the wider finances as well, a solicitor-drafted clean break consent order turns it into a court-approved settlement, at a fixed fee with no hourly billing.
What Should You Bring If You Are Self-Employed?
Preparation shortens the process, which keeps the cost down. Bring the last two years of tax calculations and tax year overviews, your business accounts, recent management accounts or bookkeeping exports, dividend vouchers and director’s loan account details if you trade through a company, and an honest note of what is booked in for the next six months. If your accountant can produce a short projection, bring that too.
Sessions run online or in person, and our teams work from Waterloo, St Pancras and Sutton, which suits people fitting mediation around client work. You can see session formats and fees on our mediation services and prices page, and if you are not married the position on property and finances differs, which we cover in our guide for unmarried parents separating in London.
Summary
Self-employed child maintenance is calculated on the taxable profit HMRC holds for you, which is a blunt instrument for income that rises and falls. A receiving parent can challenge that figure through a variation where there is unearned income, high value non-earning assets or diverted income, though that route takes time. Mediation gives London parents the option of building their own arrangement instead, with averaging, a base figure, a share of stronger years and a review date attached to the next tax return. It is usually quicker and less expensive than fighting it out, and it leaves you both able to talk when the numbers change again.
Frequently Asked Questions
What income does the CMS use for a self-employed parent?
The gross taxable profit declared on the most recent Self Assessment return, taken directly from HMRC. For a sole trader that is net profit after allowable expenses, not turnover and not drawings. For a company director it is usually salary plus dividends, with profit retained in the company outside the standard calculation.
My self-employed income has dropped. Can the CMS reduce my payments straight away?
Usually not immediately. Outside the annual review, the CMS normally needs evidence of a more recent tax return already submitted to HMRC before it will use a different figure, which can mean waiting for the tax year to end. Agreeing a private arrangement in mediation can respond to a change far faster.
What can I do if I think my ex is hiding income in their business?
You can apply to the CMS for a variation. The grounds include unearned income of £2,500 a year or more, assets each worth over £31,250 that generate no income, and diversion of income, where a parent controls how much they receive. Complex cases can be referred to the DWP Financial Investigations Unit.
Can we agree a percentage of profit instead of a fixed monthly amount?
Yes. Parents are free to agree any arrangement between themselves, and a base monthly payment plus a share of profit above an agreed threshold is a common solution for freelance and contractor income. Either parent can still apply to the CMS later, so the arrangement works best where both feel it is fair.
Does child maintenance in a consent order last forever?
No. A child maintenance clause in a court order prevents a CMS application for 12 months from the date of the order. After that, either parent can ask the CMS for an assessment, which replaces the maintenance clause. School fees and top-up maintenance for very high earners remain with the court.
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London Mediation Service helps freelancers, contractors and business owners agree child maintenance that reflects real income, with FMC-accredited mediators in Waterloo, St Pancras and Sutton, or online around your working day. We are a Legal Aid Agency contracted provider for family mediation.
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London Mediation Service, as part of Mediate UK, works with trusted legal partners including DFA Law LLP and independent barristers, who support clients with consent orders, legal documentation and advice, and independent barrister reviews.