Key Points
College savings calculators provide useful projections based on specific assumptions -- college cost inflation rate, investment return rate, and years until enrollment. The result is only as good as these assumptions. Understanding which inputs drive the most variation helps you use projections wisely and build an appropriate savings buffer.
College savings calculator assumption sensitivity
| Assumption | Base Case | Optimistic Case | Pessimistic Case | Impact on Monthly Savings |
|---|---|---|---|---|
| Investment return | 7% | 8% | 5% | ±15-20% in required monthly savings |
| College cost inflation | 5% | 4% | 6% | ±10-15% in projected future cost |
| Years until college | 18 years | N/A | 15 (child age 3) | Major impact of start date |
Use the calculator three times: once with your base assumptions, once with a 1% higher investment return and 1% lower inflation (optimistic), and once with a 1% lower return and 1% higher inflation (pessimistic). The range of results tells you the planning buffer you need to build.
What This Means for You
- The most important input is how early you start -- the timing effect dwarfs all other variables
- Investment return assumption of 7% is reasonable for equity-weighted 529 -- but not guaranteed
- Recalculate annually to keep projections current with actual account balance and new cost data
- Build a 20-30% buffer above the calculated amount to handle assumption uncertainty
- The school choice decision ultimately has more financial impact than savings calculator precision
Calculate Your College Savings
Use the college savings calculator to determine exactly how much you need to save monthly based on your child’s age, target school type, and desired coverage percentage.
Calculate Your College Savings Goal
Enter your child’s age and target school to see your personalized monthly savings plan.