"How much do I need to retire?" sounds impossibly complicated — the kind of question you leave to financial planners and spreadsheets. But you can get a genuinely useful first estimate in a few minutes with nothing more than your monthly expenses and some simple arithmetic. Here's how.
Your "retirement number" is the size of the pot of savings and investments that could support you once you stop earning a salary — living off the income and growth it produces rather than your paycheck. Knowing the rough figure turns a vague worry into a concrete goal you can actually plan toward.
The back-of-envelope method
The most widely-used rule of thumb works in three steps:
The three steps
- Estimate your yearly expenses in retirement — what it will cost you to live for a year once you've stopped working.
- Multiply by roughly 25. This is the "25× rule" (the flip side of the well-known "4% guideline" — the idea that you might sustainably draw about 4% of your pot a year).
- That's your ballpark number. If you'd need Rs. 1,200,000 a year, your target is roughly Rs. 30,000,000.
That's it for the first estimate. It's not precise, but it transforms "some huge unknown amount" into a specific figure you can aim at.
An important Sri Lankan caveat
The 25× / 4% guideline came from studies in other markets and other interest-rate environments, so treat it as a starting point, not gospel — especially here:
- Inflation. Sri Lanka has seen high inflation, which erodes what a fixed pot can buy. Your expenses in retirement will likely be much higher in rupee terms than today's, so estimate future costs, not just current ones.
- Interest rates and returns. The safe income you can earn on your pot changes with rates, which shifts how large the pot needs to be.
- Healthcare and longevity. People are living longer, and medical costs tend to rise faster than general prices. It's wise to aim a little higher than the bare rule suggests.
Because of all this, treat your number as a living estimate you revisit every few years — not a fixed finish line calculated once.
The exact number matters less than having one. A rough target you actually work toward beats a perfect figure you never calculate.
How you actually get there
Knowing the number is half the value; the other half is seeing that it's reachable. This is where two forces do the heavy lifting: regular investing and compounding. Modest amounts, invested consistently over decades, grow into sums that feel impossible when you start.
This is exactly what our savings & investment growth calculator is for — plug in what you can invest each month, a horizon, and an expected return, and watch how the pot builds. Play with the monthly amount and you'll quickly see the single most powerful lever you control: how early you start. A rupee invested in your twenties does far more work than one invested in your forties, because it has more years to compound.
Start rough, start now
Don't let the fear of getting it "wrong" stop you. Estimate your yearly expenses, multiply by 25, nudge it up for inflation and healthcare, and you have a target. Then work backwards to a monthly investing habit that heads toward it. You can refine the number every year as life changes — what you can't get back is the time you spent not starting.