This calculator compares two ways of investing the same pot of money. Option one invests the whole amount straight away. Option two splits that same amount into equal monthly investments over the number of months you choose. It is not telling you which route is best. It simply shows how the result changes under the example return you enter. Investments can fall as well as rise and you could get back less than you put in.
What this calculator assumes
- The tool is for educational illustration only and is not financial advice.
- It compares investing the full amount immediately with splitting the same amount into equal monthly investments.
- Market movements are simplified into a steady assumed return and do not capture real volatility.
- Any money waiting to be invested is treated as cash and only grows if a cash return is entered.
- Investments can go down as well as up and capital is at risk.
The comparison in plain English
Imagine you have £10,000 available. One route invests the full £10,000 today. The other route invests £833 per month for 12 months. The calculator then looks at both routes at the end of the comparison period. If the example investment return is positive and smooth, investing all the money immediately often comes out ahead because more of the money has been invested for longer. If the assumptions change, the gap can change too.
How to read the results
The “if invested all now” result assumes the full amount is invested from the start. The “if split monthly” result assumes the money is invested in equal monthly chunks. The difference result shows which route is ahead on the assumptions entered. This is not a recommendation because real markets do not grow smoothly. The useful lesson is that spreading money out may feel more comfortable, but it can also mean some money spends less time invested.
Why smoother does not mean safer
Pound-cost averaging can make the investing process feel more manageable because fewer decisions are tied to one moment. That behavioural comfort is one reason some investors use it. It does not remove market risk. If markets rise steadily, splitting the money can leave some of it entering later at higher prices. If markets fall soon after a lump sum is invested, spreading contributions can soften the immediate impact. The calculator shows that trade-off without suggesting one approach is always better.
What waiting cash means
In the monthly split route, some of the money waits before being invested. The advanced cash-return field lets you add an example return on that waiting cash. If you leave it at zero, the waiting cash does not grow before it is invested. Real outcomes depend on market movements, cash interest rates, fees, tax treatment and how consistently the plan is followed.
Useful official sources
FAQs
Does pound-cost averaging remove market risk?
No. It changes when money enters the market, but it does not remove the possibility of loss. Investment values can rise and fall and capital is at risk.
Why might regular investing produce a different result from a lump sum?
Because money enters the market at different times. That can reduce the effect of investing everything just before a fall, but it can also mean missing some gains while cash remains uninvested.
What does waiting cash mean?
It is the part of the money that has not been invested yet in the monthly split route. It may earn cash interest if you enter a cash return, but it does not receive the investment return until it is invested.
Which approach is better?
The calculator cannot answer that for you. The better choice depends on your risk tolerance, time horizon, behaviour and personal circumstances.