Student Loan Repayment Math: Standard, Graduated & Income-Based Plans

What you'll build

What you will be able to do

Each lab ends with a concrete result that you build yourself and the checker confirms, cell by cell.

• Calculate the interest Maya's four loans build up before repayment starts, add it to the balance the way capitalisation does, and find the weighted average rate she will repay at.
• Find Maya's fixed monthly payment with PMT, total what she pays over 10 years, split the first payment into interest and principal and compare longer terms.
• Solve for the first payment of a graduated plan that still clears Maya's balance in 10 years, build the five payment steps and see what the lower start costs in extra interest.
• Turn Maya's income into discretionary income, set her monthly payment as a share of it (capped at the standard payment) and follow the balance for 10 years as her income grows.
• Look up the balance left when the forgiveness clock runs out, add up what Maya paid until then, allow for a possible tax on the forgiven amount and chart how the balance moves over 25 years.
• Find how many months Maya needs when she adds 50 to 300 a month, turn that into a payoff date and measure the interest each extra amount saves.
• Price three private refinance offers against Maya's current loans, then subtract an expected value for the income-driven and forgiveness protections she would give up.
• Complete the totals for the standard and extended plans, add a possible tax on forgiveness to get each plan's total cost, name the cheapest plan with INDEX/MATCH and chart the comparison.