The 'Mostyn formula' - Adjusted Formula Methodology (AFM) ========================================================= judge Mostyn's formula for 'top-up' orders ------------------------------------------ Where there is a claim for [child maintenance](https://vardags.com/law-guide/how-the-courts-decide-a-financial-settlement/child-maintenance) and the paying party's income exceeds £156,000, the maximum level assessable under the CMS formula, the receiving party can apply for extra maintenance through the courts. This is referred to as a 'top-up' order. In order to provide clarity as to how much extra child maintenance should be awarded in such cases, Mostyn J has set out his own 'Adjusted Formula Methodology', which has also been called the 'Mostyn formula'. **If you require advice regarding how much child maintenance you or your former partner should pay, contact Vardags today for a free initial consultation with one of our expert divorce solicitors.** [BOOK FREE CONSULTATION](https://vardags.com/contact "BOOK FREE CONSULTATION") In [*TW & TM (Minors), Re* \[2015\] EWHC 3054 (Fam)](https://www.bailii.org/ew/cases/EWHC/Fam/2015/3054.html), Mostyn J held that where the paying parent's income exceeds the CMS threshold but is not "unadjacent"to it, the standard CMS formula may still be useful. Furthermore, in [*CB v KB* \[2019\] EWFC 78](https://www.bailii.org/ew/cases/EWFC/HCJ/2019/78.html) he set out that the starting point of the court should be to apply the CMS formula in cases where the paying parent's income is below £650,000. However, this approach faced some criticism, particularly over it producing very high figures, especially in cases where there was only one or two children. Notably, Moor J in [*CMX v EJX (French Marriage Contract)* \[2022\] EWFC 136](https://www.bailii.org/ew/cases/EWFC/HCJ/2022/136.html) highlighted the issues arising from the broad application of this approach. Moor J stated that whilst he accepted the "beauty" of the approach, in that it provided an easy calculation and potentially helped avoid dispute, it also resulted in unrealistic awards of child maintenance for high earners, as well as substantial disparities between awards for a single child, compared to awards for three. Mostyn J accepted Moor J's criticism, noting that where the paying parent's income in £650,000 the CMS formula would result in an award of £60,000 for a single child, and £33,000 for each of three children. As stated by Mostyn J, this is problematic given that one child plainly does not cost 80% more than one of a trio of children. To address these issues, in [*James v Seymour* \[2023\] EWHC 844 (Fam)](https://www.bailii.org/ew/cases/EWHC/Fam/2023/844.html) Mostyn set out his own 'Adjusted Formula Methodology' (AFM) to be applied instead of the CMS formula. This formula provides a 'Child Support Starting Point' (CSSP), which is a "loose starting point" to aid in the determination of child maintenance. Mostyn helpfully attached a table to his judgment, outlining the application of the AFM. As emphasised by Mostyn J, calculating the sum of child maintenance payable requires a discretionary balancing exercise, and the court must look at the relevant budget in each case. As such, judges are free to accept or dismiss the sum calculated by the AFM. Furthermore, Mostyn J clarified that the AFM should not be used in the following cases where: - Child maintenance is to be paid for four or more children - The paying parent's income exceeds £650,000 - The paying parent's income is largely unearned - The paying parent has no income and lives on capital **TABLE 2: FORMULA ADJUSTED** **A** **CSSP per child** **no shared care** **B** **CSSP per child:** **1/7th shared care** **C** **CSSP per child** **2/7ths shared care** **D** **CSSP per child** **3/7ths shared care** **E** **CSSP per child** **equal shared care** **No. of children** 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 **Amount of E** **156,000** 15,300 10,200 8,400 13,100 8,700 7,200 10,900 7,300 6,000 8,700 5,800 4,800 7,300 4,400 3,100 **175,000** 15,700 10,800 8,900 13,500 9,300 7,600 11,200 7,700 6,400 9,000 6,200 5,100 7,500 4,700 3,400 **195,000** 16,200 11,400 9,500 13,900 9,800 8,100 11,600 8,100 6,800 9,300 6,500 5,400 7,700 5,000 3,700 **215,000** 16,700 12,000 10,100 14,300 10,300 8,700 11,900 8,600 7,200 9,500 6,900 5,800 8,000 5,300 4,000 **235,000** 17,200 12,600 10,700 14,700 10,800 9,200 12,300 9,000 7,600 9,800 7,200 6,100 8,200 5,600 4,300 **255,000** 17,700 13,200 11,300 15,200 11,300 9,700 12,600 9,400 8,100 10,100 7,500 6,500 8,500 5,900 4,600 **275,000** 18,100 13,800 11,900 15,500 11,800 10,200 12,900 9,900 8,500 10,300 7,900 6,800 8,700 6,200 4,900 **295,000** 18,600 14,400 12,500 15,900 12,300 10,700 13,300 10,300 8,900 10,600 8,200 7,100 8,900 6,500 5,200 **315,000** 19,100 15,000 13,100 16,400 12,900 11,200 13,600 10,700 9,400 10,900 8,600 7,500 9,200 6,800 5,500 **335,000** 19,600 15,600 13,700 16,800 13,400 11,700 14,000 11,100 9,800 11,200 8,900 7,800 9,400 7,100 5,800 **355,000** 20,100 16,200 14,300 17,200 13,900 12,300 14,400 11,600 10,200 11,500 9,300 8,200 9,700 7,400 6,100 **375,000** 20,500 16,800 14,900 17,600 14,400 12,800 14,600 12,000 10,600 11,700 9,600 8,500 9,900 7,700 6,400 **395,000** 21,000 17,400 15,500 18,000 14,900 13,300 15,000 12,400 11,100 12,000 9,900 8,900 10,100 8,000 6,700 **415,000** 21,500 18,000 16,100 18,400 15,400 13,800 15,400 12,900 11,500 12,300 10,300 9,200 10,400 8,300 7,000 **435,000** 22,000 18,600 16,700 18,900 15,900 14,300 15,700 13,300 11,900 12,600 10,600 9,500 10,600 8,600 7,300 **455,000** 22,500 19,200 17,300 19,300 16,500 14,800 16,100 13,700 12,400 12,900 11,000 9,900 10,900 8,900 7,600 **475,000** 22,900 19,800 17,900 19,600 17,000 15,300 16,400 14,100 12,800 13,100 11,300 10,200 11,100 9,200 7,900 **495,000** 23,400 20,400 18,500 20,100 17,500 15,900 16,700 14,600 13,200 13,400 11,700 10,600 11,300 9,500 8,200 **515,000** 23,900 21,000 19,100 20,500 18,000 16,400 17,100 15,000 13,600 13,700 12,000 10,900 11,600 9,800 8,500 **535,000** 24,400 21,600 19,700 20,900 18,500 16,900 17,400 15,400 14,100 13,900 12,300 11,300 11,800 10,100 8,800 **555,000** 24,900 22,200 20,300 21,300 19,000 17,400 17,800 15,900 14,500 14,200 12,700 11,600 12,100 10,400 9,100 **575,000** 25,300 22,800 20,900 21,700 19,500 17,900 18,100 16,300 14,900 14,500 13,000 11,900 12,300 10,700 9,400 **595,000** 25,800 23,400 21,500 22,100 20,100 18,400 18,400 16,700 15,400 14,700 13,400 12,300 12,500 11,000 9,700 **615,000** 26,300 24,000 22,100 22,500 20,600 18,900 18,800 17,100 15,800 15,000 13,700 12,600 12,800 11,300 10,000 **635,000** 26,800 24,600 22,700 23,000 21,100 19,500 19,100 17,600 16,200 15,300 14,100 13,000 13,000 11,600 10,300 **650,000** 27,100 25,000 23,200 23,200 21,400 19,900 19,400 17,900 16,600 15,500 14,300 13,300 13,200 11,800 10,500 About Us -------- Ayesha VardagFounder & President "A DIVORCE LAWYER WIDELY REGARDED AS ONE OF THE WORLD'S BEST" The Metro Vardags offer a unique approach to the law, specially tailored to the needs of HNW individuals. We offer City-quality representation for your divorce and family law needs. Our lawyers come from the very best universities and receive the very best training - they are determined, diligent, and dedicated to getting the best outcome... [read more](https://vardags.com/about-us) [BOOK FREE CONSULTATION](https://vardags.com/contact) Related Guides -------------- [Capitalising child maintenance: commutation lump sum](https://vardags.com/law-guide/how-the-courts-decide-a-financial-settlement/capitalising-child-maintenance-commutation-lump-sum "Capitalising child maintenance: commutation lump sum") [Child Maintenance: What You Need to Know](https://vardags.com/law-guide/how-the-courts-decide-a-financial-settlement/child-maintenance "Child Maintenance: What You Need to Know") [Household Expenditure Child Support Award (HECSA)](https://vardags.com/law-guide/how-the-courts-decide-a-financial-settlement/household-expenditure-child-support-award-hecsa "Household Expenditure Child Support Award (HECSA)") [My ex is refusing or unable to pay child maintenance](https://vardags.com/law-guide/how-the-courts-decide-a-financial-settlement/my-ex-is-refusing-or-unable-to-pay-child-maintenance "My ex is refusing or unable to pay child maintenance") The information on this website is intended as a guide and does not constitute legal advice. Vardags do not accept liability for any errors in the information on this website, nor any losses stemming from reliance upon the statements made herein. All articles and pages aim to reflect the legal position at time they were published, and may have been rendered obsolete by subsequent developments in the law. Should you require specialist advice, tailored to your situation, please see how Vardags can help you.