Analyze student loan payments, grace-period interest, total repayment cost, and payoff timing. Compare the standard schedule with recurring extra and lump-sum payments.
Loan Inputs
$
Starting balance before grace capitalization.
%
Repayment uses a monthly approximation of simple daily interest.
years
10 years is standard for federal loans.
0–6 months are most common.
Standard Monthly Payment (no extras)
$379.84
Extra Payments
$
One-Time Extra Payments
Apply a lump sum on a specific month number (1 = first repayment month).
Payoff Date (with extras)
September 2036
Months to Payoff (with extras)
120
Time saved vs base: 0 mo
Total Interest (with extras)
$10,581.18
Interest saved vs base: $0.00
Total Extra Paid
$0.00
Remaining Balance & Cumulative Interest
- Remaining Balance
- Cumulative Interest Paid
Yearly Principal vs Interest
- Principal
- Interest
Amortization Schedule (with extras)
| # | Date | Payment | Interest | Principal | Extras | Ending Balance |
|---|---|---|---|---|---|---|
| 1 | 2026-10-01 | $379.84 | $160.42 | $219.42 | $0.00 | $34,780.58 |
| 2 | 2026-11-01 | $379.84 | $159.41 | $220.43 | $0.00 | $34,560.15 |
| 3 | 2026-12-01 | $379.84 | $158.40 | $221.44 | $0.00 | $34,338.71 |
| 4 | 2027-01-01 | $379.84 | $157.39 | $222.45 | $0.00 | $34,116.26 |
| 5 | 2027-02-01 | $379.84 | $156.37 | $223.47 | $0.00 | $33,892.79 |
| 6 | 2027-03-01 | $379.84 | $155.34 | $224.50 | $0.00 | $33,668.29 |
| 7 | 2027-04-01 | $379.84 | $154.31 | $225.53 | $0.00 | $33,442.76 |
| 8 | 2027-05-01 | $379.84 | $153.28 | $226.56 | $0.00 | $33,216.20 |
| 9 | 2027-06-01 | $379.84 | $152.24 | $227.60 | $0.00 | $32,988.60 |
| 10 | 2027-07-01 | $379.84 | $151.20 | $228.64 | $0.00 | $32,759.96 |
| 11 | 2027-08-01 | $379.84 | $150.15 | $229.69 | $0.00 | $32,530.27 |
| 12 | 2027-09-01 | $379.84 | $149.10 | $230.74 | $0.00 | $32,299.53 |
| 13 | 2027-10-01 | $379.84 | $148.04 | $231.80 | $0.00 | $32,067.73 |
| 14 | 2027-11-01 | $379.84 | $146.98 | $232.86 | $0.00 | $31,834.87 |
| 15 | 2027-12-01 | $379.84 | $145.91 | $233.93 | $0.00 | $31,600.94 |
| 16 | 2028-01-01 | $379.84 | $144.84 | $235.00 | $0.00 | $31,365.94 |
| 17 | 2028-02-01 | $379.84 | $143.76 | $236.08 | $0.00 | $31,129.86 |
| 18 | 2028-03-01 | $379.84 | $142.68 | $237.16 | $0.00 | $30,892.70 |
| 19 | 2028-04-01 | $379.84 | $141.59 | $238.25 | $0.00 | $30,654.45 |
| 20 | 2028-05-01 | $379.84 | $140.50 | $239.34 | $0.00 | $30,415.11 |
| 21 | 2028-06-01 | $379.84 | $139.40 | $240.44 | $0.00 | $30,174.67 |
| 22 | 2028-07-01 | $379.84 | $138.30 | $241.54 | $0.00 | $29,933.13 |
| 23 | 2028-08-01 | $379.84 | $137.19 | $242.65 | $0.00 | $29,690.48 |
| 24 | 2028-09-01 | $379.84 | $136.08 | $243.76 | $0.00 | $29,446.72 |
| 25 | 2028-10-01 | $379.84 | $134.96 | $244.88 | $0.00 | $29,201.84 |
| 26 | 2028-11-01 | $379.84 | $133.84 | $246.00 | $0.00 | $28,955.84 |
| 27 | 2028-12-01 | $379.84 | $132.71 | $247.13 | $0.00 | $28,708.71 |
| 28 | 2029-01-01 | $379.84 | $131.58 | $248.26 | $0.00 | $28,460.45 |
| 29 | 2029-02-01 | $379.84 | $130.44 | $249.40 | $0.00 | $28,211.05 |
| 30 | 2029-03-01 | $379.84 | $129.30 | $250.54 | $0.00 | $27,960.51 |
| 31 | 2029-04-01 | $379.84 | $128.15 | $251.69 | $0.00 | $27,708.82 |
| 32 | 2029-05-01 | $379.84 | $127.00 | $252.84 | $0.00 | $27,455.98 |
| 33 | 2029-06-01 | $379.84 | $125.84 | $254.00 | $0.00 | $27,201.98 |
| 34 | 2029-07-01 | $379.84 | $124.68 | $255.16 | $0.00 | $26,946.82 |
| 35 | 2029-08-01 | $379.84 | $123.51 | $256.33 | $0.00 | $26,690.49 |
| 36 | 2029-09-01 | $379.84 | $122.33 | $257.51 | $0.00 | $26,432.98 |
| 37 | 2029-10-01 | $379.84 | $121.15 | $258.69 | $0.00 | $26,174.29 |
| 38 | 2029-11-01 | $379.84 | $119.97 | $259.87 | $0.00 | $25,914.42 |
| 39 | 2029-12-01 | $379.84 | $118.77 | $261.07 | $0.00 | $25,653.35 |
| 40 | 2030-01-01 | $379.84 | $117.58 | $262.26 | $0.00 | $25,391.09 |
| 41 | 2030-02-01 | $379.84 | $116.38 | $263.46 | $0.00 | $25,127.63 |
| 42 | 2030-03-01 | $379.84 | $115.17 | $264.67 | $0.00 | $24,862.96 |
| 43 | 2030-04-01 | $379.84 | $113.96 | $265.88 | $0.00 | $24,597.08 |
| 44 | 2030-05-01 | $379.84 | $112.74 | $267.10 | $0.00 | $24,329.98 |
| 45 | 2030-06-01 | $379.84 | $111.51 | $268.33 | $0.00 | $24,061.65 |
| 46 | 2030-07-01 | $379.84 | $110.28 | $269.56 | $0.00 | $23,792.09 |
| 47 | 2030-08-01 | $379.84 | $109.05 | $270.79 | $0.00 | $23,521.30 |
| 48 | 2030-09-01 | $379.84 | $107.81 | $272.03 | $0.00 | $23,249.27 |
| 49 | 2030-10-01 | $379.84 | $106.56 | $273.28 | $0.00 | $22,975.99 |
| 50 | 2030-11-01 | $379.84 | $105.31 | $274.53 | $0.00 | $22,701.46 |
| 51 | 2030-12-01 | $379.84 | $104.05 | $275.79 | $0.00 | $22,425.67 |
| 52 | 2031-01-01 | $379.84 | $102.78 | $277.06 | $0.00 | $22,148.61 |
| 53 | 2031-02-01 | $379.84 | $101.51 | $278.33 | $0.00 | $21,870.28 |
| 54 | 2031-03-01 | $379.84 | $100.24 | $279.60 | $0.00 | $21,590.68 |
| 55 | 2031-04-01 | $379.84 | $98.96 | $280.88 | $0.00 | $21,309.80 |
| 56 | 2031-05-01 | $379.84 | $97.67 | $282.17 | $0.00 | $21,027.63 |
| 57 | 2031-06-01 | $379.84 | $96.38 | $283.46 | $0.00 | $20,744.17 |
| 58 | 2031-07-01 | $379.84 | $95.08 | $284.76 | $0.00 | $20,459.41 |
| 59 | 2031-08-01 | $379.84 | $93.77 | $286.07 | $0.00 | $20,173.34 |
| 60 | 2031-09-01 | $379.84 | $92.46 | $287.38 | $0.00 | $19,885.96 |
| 61 | 2031-10-01 | $379.84 | $91.14 | $288.70 | $0.00 | $19,597.26 |
| 62 | 2031-11-01 | $379.84 | $89.82 | $290.02 | $0.00 | $19,307.24 |
| 63 | 2031-12-01 | $379.84 | $88.49 | $291.35 | $0.00 | $19,015.89 |
| 64 | 2032-01-01 | $379.84 | $87.16 | $292.68 | $0.00 | $18,723.21 |
| 65 | 2032-02-01 | $379.84 | $85.81 | $294.03 | $0.00 | $18,429.18 |
| 66 | 2032-03-01 | $379.84 | $84.47 | $295.37 | $0.00 | $18,133.81 |
| 67 | 2032-04-01 | $379.84 | $83.11 | $296.73 | $0.00 | $17,837.08 |
| 68 | 2032-05-01 | $379.84 | $81.75 | $298.09 | $0.00 | $17,538.99 |
| 69 | 2032-06-01 | $379.84 | $80.39 | $299.45 | $0.00 | $17,239.54 |
| 70 | 2032-07-01 | $379.84 | $79.01 | $300.83 | $0.00 | $16,938.71 |
| 71 | 2032-08-01 | $379.84 | $77.64 | $302.20 | $0.00 | $16,636.51 |
| 72 | 2032-09-01 | $379.84 | $76.25 | $303.59 | $0.00 | $16,332.92 |
| 73 | 2032-10-01 | $379.84 | $74.86 | $304.98 | $0.00 | $16,027.94 |
| 74 | 2032-11-01 | $379.84 | $73.46 | $306.38 | $0.00 | $15,721.56 |
| 75 | 2032-12-01 | $379.84 | $72.06 | $307.78 | $0.00 | $15,413.78 |
| 76 | 2033-01-01 | $379.84 | $70.65 | $309.19 | $0.00 | $15,104.59 |
| 77 | 2033-02-01 | $379.84 | $69.23 | $310.61 | $0.00 | $14,793.98 |
| 78 | 2033-03-01 | $379.84 | $67.81 | $312.03 | $0.00 | $14,481.95 |
| 79 | 2033-04-01 | $379.84 | $66.38 | $313.46 | $0.00 | $14,168.49 |
| 80 | 2033-05-01 | $379.84 | $64.94 | $314.90 | $0.00 | $13,853.59 |
| 81 | 2033-06-01 | $379.84 | $63.50 | $316.34 | $0.00 | $13,537.25 |
| 82 | 2033-07-01 | $379.84 | $62.05 | $317.79 | $0.00 | $13,219.46 |
| 83 | 2033-08-01 | $379.84 | $60.59 | $319.25 | $0.00 | $12,900.21 |
| 84 | 2033-09-01 | $379.84 | $59.13 | $320.71 | $0.00 | $12,579.50 |
| 85 | 2033-10-01 | $379.84 | $57.66 | $322.18 | $0.00 | $12,257.32 |
| 86 | 2033-11-01 | $379.84 | $56.18 | $323.66 | $0.00 | $11,933.66 |
| 87 | 2033-12-01 | $379.84 | $54.70 | $325.14 | $0.00 | $11,608.52 |
| 88 | 2034-01-01 | $379.84 | $53.21 | $326.63 | $0.00 | $11,281.89 |
| 89 | 2034-02-01 | $379.84 | $51.71 | $328.13 | $0.00 | $10,953.76 |
| 90 | 2034-03-01 | $379.84 | $50.20 | $329.64 | $0.00 | $10,624.12 |
| 91 | 2034-04-01 | $379.84 | $48.69 | $331.15 | $0.00 | $10,292.97 |
| 92 | 2034-05-01 | $379.84 | $47.18 | $332.66 | $0.00 | $9,960.31 |
| 93 | 2034-06-01 | $379.84 | $45.65 | $334.19 | $0.00 | $9,626.12 |
| 94 | 2034-07-01 | $379.84 | $44.12 | $335.72 | $0.00 | $9,290.40 |
| 95 | 2034-08-01 | $379.84 | $42.58 | $337.26 | $0.00 | $8,953.14 |
| 96 | 2034-09-01 | $379.84 | $41.04 | $338.80 | $0.00 | $8,614.34 |
| 97 | 2034-10-01 | $379.84 | $39.48 | $340.36 | $0.00 | $8,273.98 |
| 98 | 2034-11-01 | $379.84 | $37.92 | $341.92 | $0.00 | $7,932.06 |
| 99 | 2034-12-01 | $379.84 | $36.36 | $343.48 | $0.00 | $7,588.58 |
| 100 | 2035-01-01 | $379.84 | $34.78 | $345.06 | $0.00 | $7,243.52 |
| 101 | 2035-02-01 | $379.84 | $33.20 | $346.64 | $0.00 | $6,896.88 |
| 102 | 2035-03-01 | $379.84 | $31.61 | $348.23 | $0.00 | $6,548.65 |
| 103 | 2035-04-01 | $379.84 | $30.01 | $349.83 | $0.00 | $6,198.82 |
| 104 | 2035-05-01 | $379.84 | $28.41 | $351.43 | $0.00 | $5,847.39 |
| 105 | 2035-06-01 | $379.84 | $26.80 | $353.04 | $0.00 | $5,494.35 |
| 106 | 2035-07-01 | $379.84 | $25.18 | $354.66 | $0.00 | $5,139.69 |
| 107 | 2035-08-01 | $379.84 | $23.56 | $356.28 | $0.00 | $4,783.41 |
| 108 | 2035-09-01 | $379.84 | $21.92 | $357.92 | $0.00 | $4,425.49 |
| 109 | 2035-10-01 | $379.84 | $20.28 | $359.56 | $0.00 | $4,065.93 |
| 110 | 2035-11-01 | $379.84 | $18.64 | $361.20 | $0.00 | $3,704.73 |
| 111 | 2035-12-01 | $379.84 | $16.98 | $362.86 | $0.00 | $3,341.87 |
| 112 | 2036-01-01 | $379.84 | $15.32 | $364.52 | $0.00 | $2,977.35 |
| 113 | 2036-02-01 | $379.84 | $13.65 | $366.19 | $0.00 | $2,611.16 |
| 114 | 2036-03-01 | $379.84 | $11.97 | $367.87 | $0.00 | $2,243.29 |
| 115 | 2036-04-01 | $379.84 | $10.28 | $369.56 | $0.00 | $1,873.73 |
| 116 | 2036-05-01 | $379.84 | $8.59 | $371.25 | $0.00 | $1,502.48 |
| 117 | 2036-06-01 | $379.84 | $6.89 | $372.95 | $0.00 | $1,129.53 |
| 118 | 2036-07-01 | $379.84 | $5.18 | $374.66 | $0.00 | $754.87 |
| 119 | 2036-08-01 | $379.84 | $3.46 | $376.38 | $0.00 | $378.49 |
| 120 | 2036-09-01 | $380.22 | $1.73 | $378.49 | $0.00 | $0.00 |
Key Insights
- Every $50/month extra typically cuts several months off a 10-year term and saves thousands in interest. Small, consistent extras compound powerfully.
- Grace-period interest is modeled as simple interest on the starting principal and capitalized once when repayment begins when the toggle is on. Turn it off for qualifying subsidized-loan grace periods.
- Front-loaded interest: early payments mostly cover interest. Extras made in the first 2–3 years have the greatest impact on total interest and payoff time.
For planning/education only — not financial advice.
Methodology & Formulas
- Monthly rate:
r = APR/12 - Fixed payment:
PMT = P·r / (1 - (1 + r)^(-n))(ifr = 0thenPMT = P/n) - Monthly interest:
I_t = B_(t-1) · r - Principal from payment:
PP_t = PMT - I_t - Extras:
PrincipalPlanned_t = PP_t + Extra_t(capped at remaining balance) - Balance update:
B_t = B_(t-1) - PrincipalApplied_t - Grace capitalization:
B = P + P·r·m, followed by standard amortization of the capitalized balance.
How to Use
- Enter principal, APR, term, and start month; add a grace period if applicable.
- Use Monthly/One-time extras to test payoff acceleration.
- Compare outputs and charts to evaluate time and interest saved.
- Export the schedule CSV to share or archive.
Explore Education & Learning
Student loans, education savings, and ROI calculators
View all education & learning calculators →Related Calculators
Social Security Break-Even Calculator
Compare two Social Security claiming ages by month. Use worker benefit factors or your own SSA estimates to find cumulative payouts, present value and the break-even age.
Heat Pump Water Heater vs Electric or Gas
Estimate hybrid heat pump water heater payback against an electric or gas tank using UEF, water demand, utility rates, installation costs, and rebates.
Term Life vs Whole Life (BTID)
Compare buying term and investing the premium difference with whole-life guaranteed and illustrated cash value and death-benefit timing.
Tuition Reimbursement Clawback
Compare leaving now and repaying employer tuition assistance with staying through the service commitment using salary, bonuses, vesting, and taxes.