What is the Duxbury Calculation in UK Divorce?
The ‘Duxbury’ calculation is a method used in financial remedy proceedings on divorce or dissolution in England and Wales to work out the lump sum capital needed to meet a person’s future income needs. It assumes that the recipient will invest the capital and gradually draw on both the income and capital over their lifetime. It is commonly used to help achieve a clean break, allowing the parties to end their financial relationship rather than remaining connected through ongoing maintenance payments.
The calculation is named after the 1987 Court of Appeal case Duxbury v Duxbury. In that case, a team of financial experts decided on a way to work out a wife’s lifetime income needs and the capital sum required to meet them. The resulting approach became widely adopted in financial remedy proceedings and is now a standard tool in divorce law across England and Wales.
Duxbury calculations are most relevant in medium to high-value financial remedy cases, where there are enough assets to fund a clean-break settlement. In cases where assets are limited, there may simply not be enough capital available to replace maintenance with a lump sum. It is most commonly considered where:
- One spouse has an ongoing need for financial support and one or both parties want a clean break rather than ongoing maintenance
- The court is considering whether maintenance can be converted into capital
How does a Duxbury Calculation work?
The Duxbury calculation uses a set of actuarial assumptions to produce a lump sum figure. It works as follows:
- The recipient’s income need is identified – The parties or the court determine the net annual income the recipient needs to maintain their lifestyle. This is often done by drawing up a detailed budget.
- Life expectancy is considered – The calculation takes into account the recipient’s current age and expected lifespan, based on standard actuarial data.
- An investment return is assumed – The Duxbury model assumes the lump sum will be invested. A conservative net real rate of return (after inflation and tax) of approximately 3.75% per year is typically used.
- The lump sum is calculated – The figures are combined to produce a capital sum that, if invested and drawn down annually, will last exactly until the recipient’s expected death, leaving neither a surplus nor a shortfall.
- Tax considerations are factored in – The calculation accounts for the taxes the recipient would pay on income drawn from the invested sum, so that the net income available meets their stated needs. Note that the traditional Duxbury model assumed the recipient would receive the full UK State Pension at retirement age. However, following the Duxbury Working Party’s November 2024 final report, the calculation should no longer default to including the State Pension. This is because State Pension entitlement generally depends on the recipient’s own National Insurance record, although their actual entitlement may still affect the award.
- Management fees are deducted – Following the 2024 updates, the calculation adds an allowance for investment management charges (typically 1% for funds under £1m) to prevent the capital from being eroded by fees
What are Duxbury Tables?
Duxbury Tables are pre-calculated reference tables, published annually in the Family Law Bar Association: At a Glance volumes, which legal practitioners use to identify the appropriate lump sum for a given set of circumstances. The tables have columns setting out different levels of annual net income need, and rows setting out the recipient’s current age. A practitioner can look up the relevant row and column to identify the Duxbury multiplier, which is then applied to the recipient’s net annual income need to arrive at the required capital figure.
Duxbury calculation example
In this scenario, a 60-year-old spouse needs £20,000 net per year in a clean break divorce. Using the current Duxbury Tables, the multiplier for a 60-year-old woman is approximately 15.6 (this figure varies and practitioners should always use the current edition of the tables). The required lump sum would therefore be:
£20,000 x 15.6 = £312,000
This means that, if the recipient invests £312,000 and draws down a combination of income and capital each year, the fund should last until her expected death at around age 85, providing her with £20,000 per year throughout that period.
Note: This is a simplified illustration based on the traditional whole-life Duxbury approach.
Pros and cons of a Duxbury Calculation
A Duxbury calculation offers certainty and can facilitate a clean break, but it shifts the financial risk to the recipient because it relies on fixed assumptions that may not reflect what actually happens over time. The pros and cons are set out below.
Pros of a Duxbury calculation:
- Supports a clean break – It can help estimate the lump sum needed to replace ongoing spousal maintenance, allowing the parties to achieve a clean break where appropriate.
- Certainty for both parties – Once the lump sum is agreed or ordered, neither party has any further financial obligation to the other in respect of maintenance. There is no risk of the payer losing their job or the recipient’s needs changing in ways that trigger future litigation.
- Flexibility for the recipient – The recipient receives capital they can manage and invest as they choose, rather than depending on regular payments from a former spouse.
- Reduces ongoing conflict – A clean break means the parties are less likely to return to court in the future over changes in circumstances.
Cons of a Duxbury calculation:
- Based on assumptions – The calculation relies on assumptions about investment returns, inflation, and life expectancy that may not hold true in practice. If the recipient lives longer than expected, or investment returns are poor, the fund may run out early.
- Younger recipients may not receive enough – For younger recipients with many decades of need ahead, the lump sum can appear lower than might be expected, because the model assumes investment growth over a long period. This is sometimes referred to as the ‘Duxbury paradox’.
- Requires sufficient capital – The approach is only viable where there are enough assets available to fund the lump sum. In lower-value cases, there may simply not be enough money to make a clean break achievable.
- No adjustment for changed circumstances – Unlike ongoing maintenance, a Duxbury lump sum cannot be varied if circumstances change significantly after the order is made.
The Duxbury calculation is not suitable in every case. There are other ways of calculating a clean-break settlement, such as a negotiated lump sum, a needs-based assessment, or an asset-based clean break, and the approach taken will always depend on the specific facts of each case.
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