How a TSP loan works
You borrow from your own balance, repay through payroll over the term you choose, and the interest goes back into your own account. Because the borrowed money is out of the funds while you repay it, the real cost is the return you give up on it, not the interest. The fee is a separate cost: $50 for a general purpose loan, $100 for a primary residence loan.
What this calculator compares
- Leave it invested: the loan amount stays in the TSP and earns the return you assume.
- Borrow and repay: the amount leaves; your payments, with interest, go in and then earn the same return.
- The difference is shown after the term, or after a longer horizon you choose. If the loan rate equals the return, the difference is zero.
Related tools
- TSP contribution calculator for the annual limits and the agency match.
- TSP early withdrawal penalty for the 10% additional tax rules.
Frequently asked questions
What kinds of TSP loans are there?
A general purpose loan, repaid over 12 to 60 months, can be used for anything and needs no documentation; it has a $50 fee. A primary residence loan, repaid over 61 to 180 months, is for buying or building your main home, needs documentation, and has a $100 fee. The smallest loan is $1,000.
How much can I borrow?
The most you can borrow is the smallest of three limits: your own contributions and their earnings (not agency contributions, and not counting any loan you still owe); half of your own contributions and earnings, or $10,000 if that is more, minus any loan you still owe; and $50,000 minus the highest loan balance you had in the last 12 months. The calculator's borrowing-limit section applies all three.
What interest rate will I pay?
The rate is the G Fund interest rate for the month before you request the loan, and it stays fixed for the life of the loan. Enter the rate TSP publishes; this page does not guess it.
Is the interest I pay a loss?
Not in the usual sense. You repay your own TSP account with interest, so the interest comes back to you. The cost of a TSP loan is that the money you borrow earns nothing in the TSP until it is repaid. If the account would have earned more than the loan rate, borrowing leaves you with less; if it would have earned less, you come out ahead. Returns are uncertain, so the tool lets you try different assumptions.
Is a TSP loan taxable?
No, a loan is not taxable income as long as you repay it. If a loan is not repaid and is declared a taxed distribution, the unpaid balance can be taxable and, if you are under 59½, can add a 10% additional tax unless an exception applies.
What happens if I leave federal service with a loan?
Payroll deductions stop when you leave, and TSP gives you a limited time to repay the balance. An unpaid balance can be declared a taxable distribution. If you may separate or retire before the loan is paid off, check TSP's loan booklet and use the separation option in the calculator to see what would be owed.
Should I take a TSP loan?
This tool does not say. It shows the payment, the fee and the effect on your account under assumptions you choose. Loans, in-service withdrawals and other borrowing have different costs and risks, and your own situation decides what makes sense.
Is anything I enter stored or sent?
No. The calculation runs in your browser, and nothing you enter is sent or saved. Analytics record only that the tool was used.