What is the Compound Interest Comparison Calculator?
The Compound Interest Comparison Calculator helps you see how your savings could grow over time under different combinations of time horizon and growth rate. By modelling your starting pot, monthly contributions, and several scenarios side by side, it shows how powerful compound growth can be and how much of your future pot comes from your own contributions versus investment growth.
How the Calculator Works?
This calculator models your starting lump sum and ongoing monthly contributions, then applies different annual growth rates and time horizons in parallel. It compounds growth month by month and lets you choose whether contributions are paid at the start or the end of each month. For each scenario it calculates the total amount you have paid in, the total growth generated, and the final pot size, then displays everything in a clear comparison table with simple visual bars.
Step One: Enter your contributions
Add your starting lump sum and monthly contribution. These figures remain the same across all scenarios, so you can clearly compare how time and growth affect results.
Step Two: Add growth scenarios
Create one or more scenarios with different time horizons and annual growth rates. Rename them however you like (for example, Conservative, Balanced, or Growth). This lets you compare different investing paths side by side.
Step Three: Review the results
See how much you contribute, how much growth is generated, and the final pot for each scenario. The comparison table and visual bars show instantly which combination of time and growth delivers the biggest outcome.
Disclaimer:
This calculator provides illustrative projections only and should not be taken as financial advice. Investment values can go down as well as up, and actual returns will differ from the fixed rates used here. Consider speaking with a qualified financial adviser before making significant financial decisions.
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What is the Compound Interest Calculator?
This section answers common questions about how the Compound Interest Comparison Calculator works and how to get the most from it.
What is the Compound Interest Comparison Calculator?
The Compound Interest Comparison Calculator is an interactive tool that lets you compare several compound growth paths side by side. Instead of forcing you to pick a single rate and time horizon, it shows how different combinations of years and growth rates change your final pot, while keeping your contributions consistent across all scenarios.
What does this calculator do?
It takes your lump sum, your monthly contribution, and a set of growth scenarios, then projects how your money could grow over time. For each scenario, it calculates your total contributions, the total growth generated by compounding, and the final pot value at the end of the chosen time horizon.
What information do I need to use it?
You only need three pieces of information to get started:
- Your current lump sum, if any
- How much you plan to contribute each month
- A few scenarios combining time horizons in years and expected annual growth rates
You can then refine the scenarios to reflect different risk levels or investing time frames.
Does it include tax, fees, or inflation?
No. The calculator focuses on pure compound growth and treats the rates you enter as net of any tax, fees, or inflation. In practice, charges, tax treatment, and rising prices will affect your real returns. You can experiment with lower growth rates to approximate the impact of these factors if you like.
How accurate are the results?
The maths for compounding and contributions is precise for the inputs you provide, but the real uncertainty is in the future growth rates. Markets are unpredictable, so the figures should be treated as planning guides rather than promises. Comparing several scenarios can help you understand the range of possible outcomes.
Is my information stored or shared?
No. All calculations run in your browser on your device. The site does not store or transmit your figures, which helps keep your planning private.
Is this financial advice?
No. This tool is provided for general education and planning only and does not take into account of your full circumstances, goals, or risk tolerance. If you need personalised recommendations, you should speak to a regulated financial adviser.