Income Growth Calculator

Income Growth Explained

What does this calculator show?

It projects a child's weekly earnings, portfolio value, and parent boost as reinvested income compounds over time.

Move the sliders to see how investment ratio, growth rate, dividend yield, and parent boost change the path.

How does parent boost work?

The chart always starts at your initial weekly earnings. Parent boost amplifies earnings growth above that starting level, then fades toward 1x as the portfolio grows. Boost decay controls how quickly that fade happens.

Formula

unboosted = portfolio × weeklyYield
weeklyEarnings = unboosted
  + max(0, unboosted − initialWeekly) × (boost − 1)

boost = 1 + (growthBoost − 1)
        / (1 + relativeGrowth × boostDecay / (1 − boostDecay))

Where:

• growthBoost is the Growth boost slider (for example 20x)
• relativeGrowth is portfolio growth since the start, divided by the starting portfolio
• boostDecay is the Boost decay slider from 0 (no fade) to 1 (fastest fade)

Raising growth boost does not change the series starting point; it increases how quickly earnings grow from there.

How are weekly earnings calculated?

Each week, earnings come from the portfolio's dividend yield, then multiplied by the current parent boost.

Formula

weeklyYield = effectiveDividend / 52
weeklyEarnings = portfolio × weeklyYield × boost

A 4% Average dividend is about 0.077% per week. Boost then scales that yield up while it is still above 1x.

What does the investment ratio do?

Investment ratio is the share of each week's earnings added back into the portfolio. The rest is treated as spent.

Each week

portfolio = (portfolio + weeklyEarnings × investmentRatio)
           × (1 + weeklyGrowth)

The shaded band on the chart is the range from investing none (0%) to investing all (100%). The solid line is the ratio you choose.

Is this calculator financial advice?

No. This tool is educational and shows a simplified projection.

Actual investment returns vary and may include fees, taxes, and market risk.