College Savings Calculator Formula

Understand the math behind the college savings calculator. Each variable explained with a worked example.

Formulas Used

Estimated Total Cost

total_cost_out = total_cost

Monthly Savings Needed

monthly_needed = gap > 0 ? (monthly_rate > 0 ? gap * monthly_rate / (pow(1 + monthly_rate, num_months) - 1) : gap / num_months) : 0

Current Savings Will Grow To

future_savings_out = future_savings

Variables

VariableDescriptionDefault
annual_costAnnual College Cost(USD)30000
college_yearsYears of College(years)4
years_untilYears Until College(years)10
current_savingsCurrent College Savings(USD)5000
annual_returnExpected Annual Return(%)6
total_costDerived value= annual_cost * college_yearscalculated
monthly_rateDerived value= annual_return / 12 / 100calculated
num_monthsDerived value= years_until * 12calculated
future_savingsDerived value= current_savings * pow(1 + monthly_rate, num_months)calculated
gapDerived value= total_cost - future_savingscalculated

How It Works

College Savings Calculation

Total Cost = Annual Cost × Years

The monthly savings needed is calculated by finding the gap between the total cost and what your current savings will grow to, then solving for the PMT needed to fill that gap.

Worked Example

$30,000/year for 4 years, 10 years away, $5,000 saved, 6% returns.

annual_cost = 30000college_years = 4years_until = 10current_savings = 5000annual_return = 6
  1. 01Total cost = $30,000 × 4 = $120,000
  2. 02Current savings in 10 years = $5,000 × 1.005^120 = $9,097
  3. 03Gap = $120,000 - $9,097 = $110,903
  4. 04Monthly savings needed = ~$679

Ready to run the numbers?

Open College Savings Calculator