Investing
Savings & investment growth
Project how recurring contributions and compounding may grow a balance — HYSA, bonds, stocks, or a mix — over time.
Your details
Projected balance
$1,328,618
Total contributed
$190,000
Growth from returns
$1,138,618
How this growth projection is built
This is a constant-rate compounding model. Each period, the balance grows by the periodic rate (annual rate ÷ periods per year), then the contribution is added at the end of the period. Repeat for the number of periods in your horizon. Markets do not do this. The page exists so you can see magnitude: time and contributions versus a rate you chose.
What moves the result
In early years, contributions dominate. Later, returns on a larger base do more of the work. Frequency (monthly vs annual compounding) matters less than people expect once the rate and the contribution are fixed. Doubling the contribution usually beats chasing an extra 0.5% of assumed return.
The default ~10% nominal rate is a rough long-term US equity shortcut, not a promise. Cash and bonds need a lower input. Fees and taxes are not subtracted. The breakdown’s “growth from returns” is projected balance minus total contributed.
Worked sketch
$10,000 starting balance, $500/month, 7% annual, monthly compounding, 20 years: you contribute $10,000 + $500 × 240 = $130,000. The projected balance is substantially higher than $130,000 because returns compound on both the seed and the deposits. Drop the rate to 0% and the projection equals contributions — that is the “cash under the mattress” line.
Use the historical-return presets as starting points, then open two tabs to compare rates. Pair with future inflation if you want a purchasing-power check on the same dollars.
Frequently asked questions
Read how compound interest works
How is growth calculated?
Each period, your balance grows by the periodic return (annual return ÷ periods per year), then your contribution is added. This calculator assumes contributions at the end of each period and compounding at the same frequency as your contributions.
Can I use this for savings, stocks, and other accounts?
Yes. Use the return presets or enter your own rate — savings and HYSA for cash, bonds for fixed income, balanced or stocks for portfolio-style projections. This is a simplified model with a steady return, not a year-by-year market simulation.
What contribution frequencies are supported?
You can choose daily, weekly, bi-weekly, monthly, quarterly, semi-annual, or annual contributions. The compounding interval matches your contribution frequency — for example, weekly contributions compound weekly.
What return rate should I use?
Use the presets as starting points: savings ~4.5%, bonds ~5%, balanced portfolio ~7%, stocks ~10%, or aggressive ~12%. Actual returns vary widely. Pick a rate that fits what you are modeling, not a guarantee.
Does this account for taxes or inflation?
No. Results show nominal growth before taxes, fees, and inflation. Expand the breakdown to compare total contributed vs growth from returns. For purchasing power over time, use the Future Inflation calculator.
Is this an investment growth calculator?
Yes. Enter an initial amount, optional contributions, a return assumption, and years. It projects a future balance with compound growth. The rate is a planning input, not a quote of what any account will earn.
How much will a lump sum earn in a year?
At a steady rate, interest ≈ starting balance × rate (before contributions, taxes, and fees). Example: $300,000 at 5% is about $15,000 in year one if nothing is added or withdrawn. Markets are not steady — pick a rate you are willing to defend.
Compare this
Two paths, same math — pick the number that matches the decision.
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