We have some exciting news to share! The Motley Fool UK has now become The Twelfth Magpie -- an independent, UK-owned company, led by our long-serving UK management team — Mark Rogers, Chris Nials and Heather Adlington. In practical terms, it’s the same team you know, now fully focused on serving our UK readers and members.

Just as importantly, our approach remains unchanged: long-term, jargon-free, and on your side. This site is our new home, and there will be extra tweaks made across the coming few days as we settle in. So if anything looks a little off, please bear with us!

The content of this article was relevant at the time of publishing. Circumstances change continuously and caution should therefore be exercised when relying upon any content contained within this article.

How much do I need to invest in my ISA for a second income of £20,000 a year?

Looking to earn a £20k second income from a portfolio of dividend stocks? Charlie Carman explores the amount he’d need to invest to achieve this goal.

Mature Caucasian woman sat at a table with coffee and laptop while making notes on paper

Image source: Getty Images

You’re reading a free article with opinions that may differ from The Twelfth Magpie’s Premium Investing Services. Become a member today to get instant access to our top analyst recommendations, in-depth research, investing resources, and more. Learn more, and get a free 'Best Buy Now' stock!.

Earning a second income from the stock market is a key objective for many investors, including me. With the ability to earn tax-free capital gains and dividends from a Stocks and Shares ISA, I think it’s possible to achieve this ambition by pursuing a long-term investing strategy.

But how much would I need to invest to earn £20,000 in annual dividend income? And how long would it take to build a big enough portfolio? Let’s crunch the numbers.

Should you buy Rolls Royce shares today?

Before you decide, please take a moment to review this report first. Despite ongoing uncertainties from US tariffs to global conflicts, Mark Rogers and his team believe many UK shares still trade at substantial discounts, offering savvy investors plenty of potential opportunities to learn about.

That’s why this could be an ideal time to secure this valuable research – Mark’s analysts have scoured the markets to reveal 5 of his favourite long-term ‘Buys’. Please, don’t make any big decisions before seeing them.

Please note that tax treatment depends on the individual circumstances of each client and may be subject to change in future. The content in this article is provided for information purposes only. It is not intended to be, neither does it constitute, any form of tax advice. Readers are responsible for carrying out their own due diligence and for obtaining professional advice before making any investment decisions.

Buying dividend stocks

With passive income as a priority, I’m looking for dividend shares.

The average dividend yield for FTSE 100 stocks is currently 3.8%. However, some sectors are renowned for high-yield dividend stocks. These include tobacco, banking and housebuilding, among others.

Examples of FTSE 100 shares that feature in my portfolio are:

  • British American Tobacco — 9% yield
  • Lloyds Bank — 5.4% yield
  • Taylor Wimpey — 8.2% yield

With a £20k annual passive income goal, there are two key numbers for my modelling assumptions to ascertain how much I need to invest and how long the journey will take.

Dividend yield

First, there’s my target dividend yield. Essentially, this is the average yield across my stocks. Variations in the yield can produce very different numbers in terms of my required portfolio value.

To illustrate this, here’s the amount I’d need to invest to earn a £20k second income from a range of yields.

Dividend yieldPortfolio value required
3%£666,667
4%£500,000
5%£400,000
6%£333,333
7%£285,714

Compound returns

Second, I need to focus on my portfolio’s compound annual growth rate (CAGR). Essentially, this figure is the percentage increase in the value of my shareholdings from ISA contributions, share price appreciation and dividends reinvested.

For instance, if I aimed for a 5% average yield, I’d need a £400k portfolio. Let’s assume I saved and invested £10 a day. Here’s how long I’d need to hit my target at different rates of return.

CAGRTime taken
3%48 years, six months
4%42 years, one month
5%37 years, four months
6%33 years, nine months
7%30 years, 10 months

So it’s clear the amount I’d need to invest for a £20k second income varies enormously depending on my average yield and my portfolio’s CAGR over time.

For example, if I invested £10 a day, stuck with a 5% target yield and my portfolio’s CAGR was 7%, I could invest £112,847 to hit my target £400k value in under 31 years.

Conversely, at a 3% CAGR, I’d need to invest £177,331 over a whopping 48.5 years to reach my goal! That’s an extra £64,484 and 17 years, eight months.

Managing risks

Dividend investing isn’t risk-free. Underwhelming returns resulting from bear markets or poor stock picks could mean my investing journey would take an incredibly long time. Or even require larger regular ISA contributions, as the above numbers demonstrate.

In addition, if companies cut or suspended their dividends, my required portfolio value would increase, as my average yield would drop.

However, via diversification and reliable dividend stock picks, it’s possible to unleash the enormous potential of compound returns. Which means I could generate a £20k second income in a reasonable timeframe for as little as a tenner a day.

Charlie Carman has positions in British American Tobacco P.l.c., Lloyds Banking Group Plc, and Taylor Wimpey Plc. The Motley Fool UK has recommended British American Tobacco P.l.c. and Lloyds Banking Group Plc. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.

More on Investing Articles

many happy international football fans watching tv
Investing Articles

Should I buy Diageo shares before the World Cup kicks off?

The World Cup is just a few days away! And its impact might be massive on Diageo shares – the…

Read more »

A rear view of a female in a bright yellow coat walking along the historic street known as The Shambles in York, UK which is a popular tourist destination in this Yorkshire city.
Investing Articles

2 high-yield ETFs to consider for a £1,615 ISA income!

Searching for ways to supercharge your passive income with ETFs? Consider these 7%+ dividend yielders in a Stocks and Shares…

Read more »

UK supporters with flag
Investing Articles

How have Lloyds shares become a dividend investor’s dream? 5 reasons why!

Looking for FTSE 100 stocks to buy for passive income? You may want to consider buying Lloyds' shares. But beware,…

Read more »

Close-up of British bank notes
Investing Articles

How are these FTSE 100 and FTSE 250 dividend stocks so cheap?!

Discover which FTSE 100 and FTSE 250 dividend stocks Royston Wild thinks are trading under value -- including a top-quality…

Read more »

Front view photo of a woman using digital tablet in London
Value Shares

How has Sage become one of the FTSE 100’s best bargain shares?

Sales and profits keep growing at double-digit rates. So why are Sage's share struggling? Royston Wild discusses this FTSE share.

Read more »

Young female couple boarding their plane at the airport to go on holiday.
Investing Articles

Can the Rolls-Royce share price reach £15.97 by the end of August?

The Rolls-Royce share price has had a solid run in the last year. Muhammad Cheema takes a look at whether…

Read more »

Santa Clara offices of NVIDIA
Investing Articles

Up 1,200% in 5 years, here’s why Nvidia could still be a brilliant value stock

An exciting new announcement that could reshape the PC industry has just pushed Nvidia stock... well, just about nowhere really.

Read more »

House models and one with REIT - standing for real estate investment trust - written on it.
Investing Articles

How investing £4.50 a day could set you on the way to a £1,505 monthly second income

How can UK stocks with high dividend yields help investors earn a meaningful second income from the price of a…

Read more »