Compound Interest vs Savings Goal: Projection and Planning
Use the compound-interest calculator to project growth and the savings-goal calculator to work backward from a target — two directions of the same math.
Compound interest projects forward: given what you have and add each month, where do you end up? A savings goal calculation runs the same growth math backward: given a target amount and deadline, what must you save each month to get there?
Using both together closes the loop — project your current plan forward, see the gap, then solve for the contribution that closes it.
Compound Interest Calculator
Project how an initial amount plus regular contributions grow at a given rate.
Open calculatorSavings Goal Calculator
Solve for the monthly contribution needed to hit a target by a deadline.
Open calculatorWhich direction do you need?
Use compound interest when…
- You know what you can save and want to see where it leads.
- You are comparing rates or compounding frequencies for money you already invest.
Use the savings goal when…
- You have a concrete target — a house deposit, a car, an emergency fund — and a date.
- You want the required monthly contribution, not a projection.
Frequently asked questions
Are the two calculators using the same formula?
Yes — both use the future value of a series with compounding. The compound-interest calculator solves for the ending balance; the savings-goal calculator rearranges it to solve for the contribution.
What return rate should I assume?
Be conservative. High-yield savings accounts track prevailing interest rates, while long-run stock market returns are historically higher but volatile. Test your plan at a lower rate than you hope for.