TSP Loan Payoff Amount: Calculate Your Balance

A TSP loan payoff amount is the amount needed to fully repay an outstanding Thrift Savings Plan loan on a particular date; it can differ from the balance shown on a recent statement because interest continues to accrue and payments may still be processing. This calculator estimates a level-payment loan balance from the original amount, APR, term, and number of payments made; enter the loan’s actual figures to estimate what remains, then confirm the exact payoff amount and payment instructions with the TSP loan servicer.

Formula

The estimated remaining balance after k equal monthly payments is:

B = P(1 + r)^k − M × ((1 + r)^k − 1) / r

• B = estimated balance after the payments, in dollars.
• P = original loan amount, in dollars.
• r = monthly interest rate, calculated as APR ÷ 1,200. APR is entered as a percent per year.
• k = number of monthly payments made.
• M = calculated level monthly payment, in dollars: P × r ÷ [1 − (1 + r)⁻ⁿ].
• n = total scheduled payments, calculated as loan term in years × 12.

The calculator uses the unrounded payment in the balance equation and displays money to the nearest cent. Actual loan records can use payment amounts rounded to cents and exact dates, so this mathematical estimate may not match a servicer’s current payoff quote.

Worked Example

Using the defaults—$20,000 principal, 8% APR, a five-year term, and 12 payments made—there are 60 scheduled payments. The monthly rate is 8 ÷ 1,200 = 0.0066667.

1. Calculate the level payment: $20,000 × 0.0066667 ÷ [1 − (1.0066667)⁻⁶⁰] = approximately $405.53 per month.
2. Calculate the balance after 12 payments: $20,000 × (1.0066667)¹² − $405.53 × [(1.0066667)¹² − 1] ÷ 0.0066667 = approximately $16,401.67.
3. The total of 12 displayed monthly payments is $405.53 × 12 = $4,866.36. This is the amount paid under the simplified example, not the remaining payoff.

Assumptions

• The interest rate remains fixed for the entire modeled term.
• Payments are equal, made monthly, and applied at regular intervals; the example treats 12 payments as completed.
• Interest accrues monthly at APR divided by 12, with monthly compounding.
• The estimate does not include administrative charges, late amounts, payment timing differences, or adjustments shown in the loan account.

How a TSP Loan Payoff Works

A TSP loan is borrowed from a participant’s Thrift Savings Plan account and repaid under the loan’s schedule. The account’s loan record and repayment setup determine the actual outstanding amount. A payoff is date-specific: the amount can change as interest accrues, scheduled payments are credited, and the servicer processes transactions. Consequently, “loan balance” and “payoff amount” are not always interchangeable.

Use the calculator as a general estimate when you know the loan’s starting principal, annual rate, term, and count of completed monthly payments. It does not access an account or determine TSP-specific terms. Get the current payoff figure, valid-through date, accepted payment methods, and instructions directly from the official loan account or servicer before sending a final payment.

Reading the Estimate and Choosing Inputs

Enter the original amount borrowed—not the amount that may have been deposited after any deductions—and the stated APR as a percentage. For example, enter 6.5 for 6.5%, not 0.065. Enter the full scheduled term in years and the number of payments actually credited. If a payment is pending or has not posted, the estimate may differ from the account’s balance.

The first result is the estimated remaining balance after the entered payments. The second is the model’s scheduled monthly payment; the third is the total of that displayed payment multiplied by the payment count. That third figure is not a payoff quote, nor does it indicate how much principal has been repaid: each payment includes both principal and interest.

• For a new loan with no payments credited, enter 0 for payments made.
• For a loan partway through repayment, count credited monthly installments rather than calendar months since borrowing.
• If the loan has a different payment frequency, variable rate, changed term, or irregular payment history, this monthly fixed-payment model may not fit it.

Why Your Account’s Amount May Differ

The estimate uses a standard amortization formula. A real payoff calculation can depend on payment dates, the precise interest-accrual method, posted transactions, and the date through which the payoff figure is valid. Cent rounding can also accumulate across many installments. If payments were missed, delayed, adjusted, or made in extra amounts, counting payments alone will not reproduce the account’s transaction history.

A common misconception is that the total of payments made should equal the principal reduction. It does not: scheduled payments also cover interest. Likewise, a displayed balance is not necessarily the exact amount to send to close the loan on a future date. The servicer’s payoff figure and instructions take precedence over this estimate.

Frequently Asked Questions

How do I find my exact TSP loan payoff amount?
Check the loan information in your official TSP account or contact the loan servicer using official contact details. Ask for the payoff amount, the date it is valid through, and the required payment instructions.

Why is my payoff amount higher than the balance I saw?
The figures may reflect different dates or transactions. Interest can accrue after a balance is displayed, and payments may not yet have posted. Request a current payoff quote to see the amount for the intended payment date.

Does making an extra payment reduce the payoff balance?
An extra payment can affect what remains if it is accepted and credited to the loan, but the timing and treatment depend on the account’s servicing rules. This calculator assumes only equal scheduled payments and does not model extra payments.

Can I use this calculator for a TSP loan with payments taken from pay?
You can use it for a rough estimate if the loan’s actual schedule is equivalent to regular monthly payments. Payroll deductions may post on a different schedule, so the number of credited payments and the account’s actual balance may not align exactly with the model.

Is the estimated balance the amount I should send?
No. It is an arithmetic estimate, not an official payoff quote or payment instruction. Confirm the amount, deadline, and payment method with the servicer before paying off the loan.

This result is an estimate; the lender’s disclosure gives the exact figures.

Related

• How to Calculate Loan Payments: Formula and Example
• Basic Loan Calculator Payment and Formula
• Term Loan EMI Calculator: Estimate Monthly Payments

in p | Original loan amount | $ | 20000 | 1 | 100000000
in apr | Interest rate (APR) | % | 8 | 0.01 | 100
in yrs | Loan term | years | 5 | 0.0833 | 50
in k | Payments made | - | 12 | 0 | 600
out bal | Estimated balance after payments | $ | p * (1 + apr / 1200) ^ k - (p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12))) * ((1 + apr / 1200) ^ k - 1) / (apr / 1200) | 2
out pmt | Estimated monthly payment | $ | p * (apr / 1200) / (1 - (1 + apr / 1200) ^ -(yrs * 12)) | 2
out paid | Payments made, total | $ | pmt * k | 2