When I set up my first ETF savings plan in 2021, the biggest question was how much to put in each month and what it would actually amount to. I had no good answer until I started running the numbers properly. Turns out the answer is more encouraging than most people expect.

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Example: £300/month · 7% · 20 years
£176,472
£99,472 in investment gains
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What Is an ETF Savings Plan?

An ETF (Exchange Traded Fund) tracks an index like the MSCI World or FTSE All World automatically. It holds hundreds or thousands of stocks globally, at very low annual costs (typically 0.1–0.2%). A savings plan invests a fixed amount automatically each month, without you having to time the market.

The Cost-Average Effect: By investing regularly, you buy more units when prices are low and fewer when prices are high. This smooths your average entry price and reduces the risk of a poorly-timed lump sum.

Concrete Numbers: What Does Monthly Saving Return?

Globally diversified ETFs (MSCI World) have historically returned around 7–8% p.a. We use a conservative 7%:

£100/month at 7% annual return

After 10 years: £17,409 (invested: £12,000) → Compounding gain: +£5,409

After 20 years: £52,397 (invested: £24,000) → Compounding gain: +£28,397

After 30 years: £121,997 (invested: £36,000) → Compounding gain: +£85,997

£200/month at 7% annual return

After 10 years: £34,819 (invested: £24,000) → Compounding gain: +£10,819

After 20 years: £104,793 (invested: £48,000) → Compounding gain: +£56,793

After 30 years: £243,994 (invested: £72,000) → Compounding gain: +£171,994

£300/month at 7% annual return

After 10 years: £52,228 (invested: £36,000) → Compounding gain: +£16,228

After 20 years: £157,190 (invested: £72,000) → Compounding gain: +£85,190

After 30 years: £365,991 (invested: £108,000) → Compounding gain: +£257,991

How to Choose the Right ETF

ETF Savings Plan vs Cash Savings Account

Both have their place. Cash savings (ISA, easy access) are ideal for your emergency fund (3–6 months' expenses) and short-term goals up to 3 years. The ETF savings plan is the tool of choice for long-term wealth building over 10+ years. The ideal combination: emergency fund in cash, everything beyond that in the ETF plan.

Risk note: ETFs are subject to market fluctuations. In crash years, values can fall 30–50% temporarily. Anyone with a long time horizon (10+ years) who can hold through volatility has historically been rewarded. For money you need within 5 years, ETFs are unsuitable.