Calculator
Sort Compound Interest Growth
Enter today’s balance, a realistic monthly add, a rate, and how often interest compounds. The chart sorts a what-if—live yields and markets still move.
A way to sort how today’s balance plus steady monthly deposits can grow under one constant rate—useful for savings sketches and learning the compounding math.
Investment details
Results
Final balance
$196,665.39
Total contributions
$82,000.00
Total interest earned
$114,665.39
Estimated growth
Yearly illustration of contributions versus estimated balance. This is not a market forecast.
Sorted Finance is an education site. Our tools and writing help you organize questions—they do not replace advice from a licensed professional.
Modeling notes: methodology.
How to use this calculator
- Put in what you hold now, then a monthly add you can actually sustain.
- Pick a rate that matches the story: a deposit APY, or a long-horizon teaching assumption—never both mixed as one “promise.”
- Choose compounding close to how the account credits (monthly is a common default).
- Stretch or shrink the years to see how time usually outranks tiny frequency tweaks.
What this estimate includes
- Growth on starting principal at one fixed nominal rate
- Ongoing monthly deposits for the full horizon
- Your chosen compounding frequency, mapped onto a monthly timeline
What it leaves out
- Taxes on interest or investment gains
- Account fees and fund expense ratios
- Year-to-year market swings and sequence risk
- Withdrawals, penalties, or paused contributions
How this calculation works
Compound interest applies to both principal and interest already credited. This sorter converts your compounding frequency into an equivalent monthly rate so monthly deposits stay on one timeline.
The ending balance assumes one constant rate for the whole period. Deposit APYs can change. Investment returns bounce year to year. Label whether you are sorting a cash-style rate or a long-run teaching assumption so the two stories stay separate.
For the idea behind the math, read how compound interest works. For deposit yield wording, see how APY works.
A = P(1 + r/n)^(n t) plus the future value of monthly contributions
P is starting principal, r is the annual rate, n is compounding periods per year, and t is years. Contributions use an equivalent monthly rate for a consistent timeline.
Worked example
Start with $2,500, add $175 a month, assume 3.5% a year compounded monthly, and wait 8 years. Cash contributions total about $19,300 over that span. The estimated ending balance is higher because interest is credited along the way (about $22,700 in this model).
Try the same deposits at 6.5% for a longer teaching horizon. The gap between rates over many years is usually larger than the gap between monthly and daily compounding at one rate—time and rate dominate tiny frequency tweaks.
Quick comparison
Round-number scenarios for orientation only—not quotes or approvals.
| Start | Monthly add | Rate | Years | Idea |
|---|---|---|---|---|
| $2,500 | $175 | 3.5% | 8 | Cash-style sketch |
| $8,000 | $250 | 6.5% | 18 | Longer growth sketch |
| $0 | $400 | 5% | 12 | Deposit-heavy path |
Practical tips
Name the rate world you are in
A 3.5% cash-style rate and a 7% long-run market sketch teach different lessons. Label the scenario so you do not treat a market path like a bank guarantee.
Deposits usually beat compounding trivia
Raising the monthly add typically moves the ending balance more than flipping from monthly to daily compounding at the same nominal rate.
Purchasing power is not in the chart
The ending dollar figure ignores inflation. For context on what those dollars may buy later, pair this tool with a purchasing-power guide.
Bottom line
Read the ending balance as a sorted what-if under a steady rate. Live accounts face fees, taxes, and changing yields—use the result to size deposits, not to lock in an outcome.
Frequently asked questions
Is the rate I enter a guaranteed yield?
No. Deposit rates can change. Investment returns vary and can be negative. The calculator holds one rate constant so you can sort the math.
When do monthly deposits land in the model?
Contributions are treated as monthly. Your compounding frequency is converted to an equivalent monthly rate so the timeline stays consistent.
Why does compounding frequency barely move the result?
At the same nominal annual rate, monthly vs. daily compounding usually adds only a little. Time, deposits, and the rate itself matter more.
Are taxes on interest included?
No. Taxable interest may be ordinary income; tax-advantaged accounts follow different rules. Nudge the rate down slightly if you want a rough after-cost sketch.
Can I include withdrawals?
Not in this version. It assumes deposits continue and no money leaves. Drawdown plans need a different model that includes spending and sequence risk.
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