Project a starting balance and real month-end contributions under annual, semiannual, quarterly, monthly, or daily nominal compounding, with exact deposit and interest reconciliation.
A quick decision brief for this specific tool
Starting balance, month-end contribution, nominal annual rate, whole-year horizon, supported crediting frequency, and optional inflation scenario
Final balance, deposits, interest, effective annual/equivalent monthly rates, real-value context, contribution comparison, milestones, charts, schedule, and CSV
The selected nominal-rate crediting frequency is converted to an effective annual and equivalent monthly rate; interest accrues monthly and every contribution is placed at month end
Choose your path
Project deterministic compound growth from a starting balance, real month-end deposits, nominal rate, compounding convention, time, and optional purchasing-power assumptions.
Match an advertised nominal rate and compounding convention without mis-timing deposits.
Enter principal, monthly deposits, rate, years, and compounding frequency; inspect deposits versus growth.
Can reproduce the timing convention and distinguish nominal rate, effective yield, and projected balance.
See how inflation changes the purchasing-power context without a fake universal tax result.
Run the same base scenario, then enable the explicit inflation assumption and compare nominal with real value.
Does not treat a smooth rate or inflation input as a forecast, and understands taxes/fees are excluded.
Compare contribution and no-contribution paths on a phone.
Load a baseline, change one assumption, inspect milestones and the year table, then copy/export.
Controls remain named/tap-sized and all result labels preserve rate, timing, and dollar basis.
This tool is part of these guided projects. Each project provides step-by-step instructions with checklists and all the tools you need in one place.
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Project deterministic investment growth from a starting value and monthly contributions, with explicit beginning- or end-of-month timing and dollar reconciliation.
Calculate total ROI and net gain or loss, then use CAGR for endpoint-only investments or money-weighted IRR for explicit year-end contributions.
For principal alone, the standard nominal-rate formula applies. The selected frequency also determines the effective annual rate and its equivalent monthly rate.
EAR = (1 + nominal rate ÷ credits per year)^(credits per year) − 1Every monthly contribution is deposited after that month's interest credit. This avoids treating twelve monthly deposits as though they all arrived at year end when annual crediting is selected.
Monthly balance = prior balance × (1 + equivalent monthly rate) + month-end contributionOptional inflation converts the final nominal balance into approximate present purchasing power. The fixed-rate projection excludes taxes, fees, withdrawals, changing rates, and volatility; it does not use a generic tax percentage as a real after-tax result.
Updated: August 2026
With monthly crediting and month-end deposits over 20 years, every dollar is separated into contribution and modeled interest.
→ Final balance: $144,572.72; deposits: $58,000; interest: $86,572.72
$1,000 plus $100 at each month end for two years at 0% finishes at exactly $3,400, with $0 interest and no divide-by-zero failure.
At the same positive nominal rate and no recurring deposit, daily crediting produces a slightly higher effective annual rate than annual crediting. Compare like-for-like nominal rates and terms.
Keep monthly deposits on monthly dates. This calculator derives an equivalent monthly rate from the selected nominal crediting frequency and deposits cash at month end.
Exact purchasing-power conversion divides the future balance by (1 + inflation)^years. Simple subtraction is only a rough rate intuition.
Test one transparent compounding scenario at a time. The calculator converts the stated nominal rate and crediting frequency to an equivalent monthly rate so recurring monthly deposits remain monthly instead of being moved to one annual date.