How long it takes to reach £100,000

£100,000 is the first round number in British saving that feels worth naming. It is far enough away to need a plan and close enough that an ordinary salary can reach it, which is why people ask about it. Most answers you will find online stop at the cash date, and they rarely explain the gap.

What the arithmetic says

Three standing orders, no starting balance, 5 per cent growth a year and 3 per cent inflation. The same engine that runs our calculator, asked the same question three times:

The second column is the one to sit with.

The gap between the two answers

At £200 a month the balance crosses £100,000 after 22 years and 10 months. That is the date most calculators print, and it is true in the narrow sense that the screen will one day read £100,000.

It is also a weak guide to what you can buy. £100,000 in 2049 is not £100,000 in today's shops. At 3 per cent inflation it buys roughly what £50,000 buys now, so the pot that finally shows six figures is worth about half of what you pictured when you set up the standing order. To hold £100,000 of today's spending power at £200 a month takes 43 years and 8 months. Nearly double.

That gap is not a rounding quirk. It is what happens when a small contribution has to outrun inflation for a long time, and it is the most useful thing this table can show you. Publishing only the cash date is the flattering version, so our calculator shows both and treats the inflation-adjusted one as the answer.

The gap also closes when you pay in more. At £500 a month it is five and a half years instead of twenty-one. At £1,000 a month it is under two. Inflation hurts most when contributions are small and the journey is long.

The part that works the other way round

Look at the last two columns and something inverts.

The person saving £200 a month pays in £54,800 and lets growth find the other £45,671. A little over 45 per cent of the pot comes from investment return, not from what they paid in. The person saving £1,000 a month pays in £85,000 and gets just £16,331 of growth, around 16 per cent.

The slow saver's money works harder in percentage terms and still arrives too late to buy what they had in mind. Time produces growth; contributions set how soon a target arrives. With a long horizon, returns can do a surprising share of the work. With a short one, no ordinary return rate fixes a contribution that is too small. Larger monthly amounts move the date more than nudging the growth assumption.

That is also why "start early" is both powerful and easy to misread. Starting early does hand work to compounding. It does not turn £200 a month into a ten-year path to £100,000 in real terms, and starting early alone will not.

Where the money sits while it does this

None of the figures above include tax, and at these sizes tax often stays out of the way. £20,000 can be paid into ISAs in the 2026 to 2027 tax year, which is more than £1,000 a month, so every row in that table fits inside a wrapper where growth and withdrawals are untaxed. For many people aiming at £100,000, the allowance answers the tax question.

If you are saving for a first home, a Lifetime ISA takes £4,000 a year and adds a 25 per cent government bonus, up to £1,000. That £4,000 counts towards the same £20,000 limit. On the £200 a month row, £2,400 a year, the bonus is £600 a year, which moves the arithmetic more than small differences in investment return would. It is also restricted: you must open one before 40 and pay in before 50, and taking the money out for anything other than a first home or reaching 60 carries a charge that can leave you with less than you put in.

What these numbers assume, and what they are not

The 5 per cent is an assumption, not a forecast. Nobody knows what the next twenty years return, and a piece that presents a growth rate as a fact is doing the same thing as a calculator that hides inflation. Change it in the tool and watch what moves. The durations shift far more when you change what you pay in than when you change the return guess, which is the opposite of how many people spend their attention.

Two smaller choices are worth stating. Contributions are counted at the end of each month, after that month's growth, which is the conservative convention. And the annual rate is converted to its true monthly equivalent instead of dividing by twelve. Dividing by twelve turns a 5 per cent assumption into slightly more than 5 per cent when compounded monthly, and over forty years that adds up.

None of this accounts for your income tax position, your pension, or what else the money might be needed for. It is arithmetic about one pot, not a plan.

Run it on your own numbers

The table above is three rows from a much larger picture, and yours will not match any of them. Our time to £100,000 calculator takes your starting balance, your monthly amount and your own assumptions, and gives you both answers side by side: the cash one and the real one.

If the real answer comes back further away than you expected, that is the calculation doing its job. It is easier to see that while a standing order can still be changed than twenty years later. If you are making a decision that turns on any of this (a pension, a property, a large sum moving at once), a regulated financial adviser who can see your whole position is the right place to take it, not a table on a website.