Compare growth assumptions without re-entering the plan
Compound growth is more useful when the assumptions stay visible. This workspace combines a starting balance, recurring monthly deposits, contribution timing, compounding frequency and inflation, then keeps the effective APY and year-by-year working beside the result.
How to use this calculator
Enter the starting balance, monthly contribution, nominal annual rate and time horizon.
Choose how often the quoted rate compounds and whether contributions arrive at the beginning or end of each month.
Set an editable inflation assumption if you want purchasing-power context.
Compare a second rate scenario, the APY-by-frequency table and the year-by-year balance breakdown.
Where people use it
- •Projecting a lump sum plus regular savings
- •Comparing the effect of different quoted rates
- •Checking how compounding frequency changes effective APY
- •Seeing nominal growth beside inflation-adjusted purchasing power
Example: same savings plan, different rate
Keep the starting balance, monthly contribution and time horizon unchanged, then change Scenario B. The difference isolates the effect of the return assumption without re-entering the rest of the plan.
Planning assumptions and limits
- •This is deterministic planning math, not a return forecast or investment recommendation.
- •It assumes a constant nominal rate and constant inflation assumption for the selected period.
- •Taxes, fees, changing rates, missed contributions and market volatility are not modeled.
- •Contribution timing can materially change long-horizon results, so match the timing to the scenario you are testing.
Frequently asked questions
What is the difference between APR and APY here?+
The annual rate input is treated as a nominal rate. APY includes the effect of the selected compounding frequency, making different compounding schedules easier to compare.
Can I include monthly deposits?+
Yes. Monthly contributions can be applied at the beginning or end of each month, and the year-by-year table separates contributed money from compound growth.
Why show inflation-adjusted value?+
A future nominal balance can buy less if prices rise. The real-value output discounts the projected balance by your editable inflation assumption.
Is Rule of 72 exact?+
No. The workspace shows both the Rule of 72 estimate and the exact doubling time implied by the effective APY.
Semantic next steps
Continue the calculation
These links move to a different input, formula or project stage rather than a keyword variation of this page.
Free publisher widget
Put this calculator on your website
Give readers the live calculator without rebuilding the math. Copy the responsive embed in one click, or customize width, height, border and corner radius before publishing. The branded MAXScanner attribution stays visible.
Calculator embed HTML
Paste this code into your page. Focus the code box to select it manually.
Keep the result connected to the real job
MAXScanner keeps the formula and assumptions beside the result so you can verify the number before using it in a drawing, estimate, specification, worksheet or document. Where a supplier, manufacturer, drawing or applicable standard owns a requirement, that source remains authoritative.