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What Is Retirement Modelling?

Why modelling your retirement matters and what a projection actually shows you.

3 min read · Last reviewed March 2026


Overview

What Retirement Modelling Shows You

From your inputs today to a picture of the future

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1

Your Situation

Income, pensions, savings, property — what you have today

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2

Your Assumptions

Growth rates, inflation, spending levels, retirement age

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3

Simulation

Year-by-year projection from now to life expectancy

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4

Results

Charts showing how your wealth evolves over time

Why model your retirement?

In brief: Retirement modelling answers one question — will my money last? By entering what you have, what you expect to earn, and what you expect to spend, you can see a year-by-year projection of how your finances might unfold over decades.

Most people approaching retirement have a rough sense of their savings, pensions, and spending — but no clear picture of how all these pieces fit together over 20 or 30 years. A retirement model takes those pieces and projects them forward, year by year, so you can see whether the numbers add up.

This isn't about predicting the future. Markets move, tax rules change, and life rarely follows a straight line. Modelling is about understanding the shape of your retirement finances under a set of assumptions you choose — and then changing those assumptions to see what difference it makes.

What a projection shows you

A retirement projection takes your current financial position — your pensions, savings, property, income — and plays it forward through time. Each year, the model:

  • Adds up your income (employment, pensions, rental income, State Pension)
  • Subtracts your spending and any tax due
  • Grows your investments by the rate you've assumed
  • Carries the result forward into the next year

The output is a year-by-year picture of your total assets from today until the end of your projection. You can see the trajectory: does your wealth grow, hold steady, or decline? And critically — does it run out before the end?

A projection is not a guarantee. It's a "what if" — if your assumptions hold, this is what the numbers look like.

What it doesn't do

Retirement modelling shows you the mathematical consequences of your inputs. It does not tell you what to do. It cannot predict market returns, inflation, or how long you'll live. It doesn't recommend products, investments, or withdrawal amounts.

This distinction matters. A model is a calculator, not an adviser. It shows the mathematical outcomes of your inputs, which you can use as context when thinking through your situation or when speaking with a financial adviser.

What to look for in a modelling tool

A useful retirement model goes beyond a simple calculator. Look for tools that:

  • Handle multiple income sources and asset types together, including the tax interactions between them
  • Model UK tax rules — income tax bands, pension tax relief, Capital Gains Tax, dividend tax — applied to your specific combination of income each year
  • Support scenarios — different versions of your retirement (retire at 60 vs. 65, spend more vs. less, downsize vs. stay put) that you can compare side by side
  • Model couples — two people with different ages, pensions, and life expectancies
  • Keep you in control — you choose the assumptions, you decide what to model, and the tool shows you the results

Who benefits most

Retirement modelling is most useful for people who want to understand their finances in more depth than a basic calculator allows. If you manage your own investments, track your pension pots, and want to see the combined picture — a detailed model helps you make better-informed decisions, whether independently or alongside professional financial advice.

These projections are for modelling purposes only. They do not constitute financial advice. Tax rules are subject to change. Please consult a qualified financial adviser before making financial decisions.

Ready to see your own numbers?

Quick Start walks you through entering your details and running your first projection in a few minutes.

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