## introduction to duxbury

###### A Duxbury Calculation is an iterative calculation, which is typically used to estimate the monetary amount a person requires to support themselves for the remainder of their life, or a fixed time period (the “Capital Sum”). This is computed on the basis of the following:
1. The person would invest this amount in an investment portfolio to achieve capital growth and income from the investments, which would be used to satisfy the required expenditure;
###### There are several variables that must be estimated to compute a Duxbury Calculation, which include:
1. life expectancy,
2. inflation rate,
3. investment portfolio, and

## duxbury formula

Duxbury Tables for 2019 are reproduced in Duxbury Etc (PDF) and bespoke calculations can be obtained from expert forensic accountants.

Alternatively, users can produce their own calculations using the simplified Duxbury Formula and multiplier tables below:

The formula:

A (multiplier) x B (desired monthly payment x 12) = L (lump sum)

A can be determined through standard multiplier tables (PDF) by reference to the appropriate discount rate for the expected period of payment (e.g. 3.5% over 12 years is 9.66).

B is determined by the annualised expected needed monthly payment excluding the impact of inflation (as inflation is accounted for in the discount rate).

The most updated data for life expectancy and inflation in Hong Kong can be retrieved from the Census and Statistics Department Website (Life Tables and Consumer Price indices). Historical yields for prudent portfolio of investment will depend upon the period of investment. Reference may be made to various tracker funds: e.g. Tracker Fund of Hong Kong.