Free tool
Compound interest
Currency
Starting amount $10,000
Monthly contribution $500
Annual return 7.0%
Time horizon 30 yrs
Compounding
Show in today's money
Projected balance after 30 years
$691,150You put in
$190,000
Interest earned
$501,150
Growth multiple
3.64×
ContributionsCompound interest
Projections assume a constant annual return with steady contributions — real markets don't move in straight lines. Currency is a display setting; no live exchange rate is applied. Educational estimate, not investment advice.
Live ETF comparison
Stack ETFs on one chart with your own key
Uses Twelve Data (free tier: 800 req/day, 8/min). Your key is stored in your browser's localStorage only — never sent to Kodama Labs.
Twelve Data API key
Tickers 2/6
SPYQQQ
Range
Bring your own API
Track SPY, VOO, QQQ and any ETF with live data — your key, your rules
Kodama Labs is going key-optional. Plug in your own market data key (Polygon, Finnhub, Alpha Vantage, Twelve Data, or Tiingo — all have free tiers) and this calculator pulls real historical returns for the tickers you care about, right into your projection. No middleman, no rate-limit sharing, no selling your queries. You own the key, we just do the math.
- Auto-pull 10 / 20 / 30-yr CAGR for SPY, VOO, QQQ, DIA, IWM, VTI, or a custom ticker
- Compare "market truth" vs your assumed rate side-by-side
- Keys stored locally in your browser — never sent to our servers