A promissory note is the simplest loan document that actually works: a signed promise from a borrower to repay a stated amount, on stated terms, to a stated person. It is what turns "I lent my brother $15,000" from a story into an enforceable debt.
The note fits personal loans, family loans, small business loans, and seller financing. What makes it enforceable is precision: the amount, the interest, the schedule, and what happens on default, each stated without ambiguity.
Promissory note or loan agreement?
A promissory note is a one-sided instrument: the borrower signs a promise to pay, and that signature alone creates the obligation. A loan agreement is a two-sided contract with mutual covenants: representations, conditions on the advance, collateral terms, and remedies. For a straightforward loan between people or small businesses, the note is usually enough and much easier to execute. Move up to a loan agreement when the loan is secured by collateral, disbursed in stages, or hedged with conditions the borrower must maintain.
| Situation | Better fit |
|---|---|
| Family loan, fixed schedule | Promissory note |
| Friend lends startup cash, single payback date | Promissory note |
| Loan secured by equipment or a vehicle | Loan agreement |
| Staged advances with conditions | Loan agreement |
| Seller financing on a small business sale | Both, note plus agreement |
Interest: usury caps and the IRS floor
Interest on a private loan is squeezed from two directions. State usury laws cap the maximum rate a private lender may charge, with limits and exemptions that vary widely by state. And on the low end, the IRS publishes the Applicable Federal Rate (AFR): family loans above roughly $10,000 that charge less than the AFR can generate imputed interest, meaning the lender may owe tax on interest they never collected, and large forgone interest can count against the annual gift exclusion. A rate at or slightly above the current AFR keeps a family loan clean on both fronts.
Zero percent is allowed, but not invisible
You can make an interest-free loan, and this template supports it. For larger family loans, be aware the IRS may still impute interest at the AFR for tax purposes; a licensed tax professional can tell you whether your amount is affected.
What a signed note is worth when things go wrong
If the borrower stops paying, the note is the evidence that wins the case: amount, terms, and signature, with no argument about whether the money was a gift. The lender sends a demand for the accelerated balance, then sues on the note, in small claims court if the amount fits the state's limit. Notes also start the statute of limitations clock for written contracts, which is longer than for oral promises in most states. Keep the signed original, record every payment received, and put any modification, like a payment holiday, in a signed writing.
Witnesses and notarization
A promissory note is valid with just the borrower's signature. Notarizing it or adding a witness does not change its force but makes the signature nearly impossible to dispute, which is worth doing for larger amounts.
For larger or more structured loans with covenants and detailed default terms, step up to a full loan agreement. If the borrower stops paying, a demand letter for payment is the standard first collection step, and a debt settlement agreement documents any compromise you reach.
When to use a promissory note
Any time money changes hands with the expectation of repayment, a note belongs in the transaction. The common cases: lending to a family member or friend for a car, tuition, a medical bill, or breathing room; seeding a relative's business; selling a vehicle, equipment, or furniture with payment over time; documenting an old undocumented loan (a note signed today for an existing debt is far better than nothing); and lending to or borrowing from your own company, where the paper keeps personal and business finances legally distinct.
One case deserves special mention: helping a family member with a home down payment. Mortgage lenders ask whether down payment funds are a gift or a loan, and the answer changes the borrower's debt ratios. If it is a loan, the lender will want to see the note; if it is a gift, a signed gift letter is the honest document, not an unwritten loan everyone quietly expects to be repaid. Deciding which one it truly is, before the money moves, prevents both mortgage fraud and family resentment.
The terms of the note, explained
The four repayment structures
Installment notes repay principal and interest in equal periodic payments until maturity, like a car loan, and fit most family lending because progress is visible. Lump-sum notes come due in full on a single date, which suits bridge situations with a known payoff event. Interest-only notes keep payments small during the term with principal due at maturity, useful for business seeding. Demand notes come due whenever the lender asks, which maximizes lender flexibility but can be harsh in families; if you use one, agree informally on expectations even though the paper says on demand.
Late charges and grace periods
A short grace period (commonly 10 to 15 days) followed by a modest late fee keeps small slips from becoming defaults while still signaling that the schedule is real. State law limits late charges on some loan types, and a fee wildly out of proportion to the harm invites a court to strike it. The fee's real function is behavioral: it makes on-time the path of least resistance.
Default and acceleration
Without an acceleration clause, a lender can only sue for the payments already missed, one batch at a time. With it, after a missed payment and any required notice, the entire remaining balance comes due at once, so a single lawsuit resolves the whole loan. The clause should say what counts as default (missed payment beyond the grace period, borrower insolvency) and what notice the lender gives before accelerating.
Co-borrowers and guarantors
Two signatures on the borrower line mean joint and several liability: the lender can collect the full amount from either signer. A guarantor signs separately, promising to pay if the borrower does not. For loans to young adults or thin-credit borrowers, a guarantor converts a hope into a credit decision. Whoever signs should understand they are signing for the whole debt, not half of it.
Family loans: keeping the loan real
The IRS and the courts share a suspicion: money that moves between relatives with no paper, no interest, and no repayments looks like a gift dressed as a loan. That matters at tax time (large gifts have reporting rules) and in disputes (an estate cannot collect a loan a court reads as a gift). The note is the first defense, and behavior is the second: charge at least a nominal rate on larger loans (the AFR keeps things clean), collect payments on schedule by traceable methods, record each one, and treat any missed payments the way an unrelated lender would, with a reminder in writing. If you later choose to forgive part or all of the loan, forgive it deliberately, in writing, understanding the gift tax treatment of the forgiven amount.
Lending from an estate planning angle
If the lender dies, the note is an estate asset: the executor collects the remaining payments or distributes the note itself. If the borrower is also an heir, the will can direct that the debt be deducted from their inheritance, which is dramatically cleaner than leaving siblings to argue about an undocumented loan.
One more family-loan habit worth adopting: put the payoff in writing too. When the last payment clears, the lender should mark the original note paid in full, sign and date it, and give it back to the borrower or send a short signed release. Years later, when an estate is settled or a mortgage underwriter asks about an old transfer, that one page answers the question instantly.
Common promissory note mistakes
- Leaving the repayment schedule vague ('when he can'), which courts struggle to enforce and families struggle to live with
- Charging interest above the state usury cap, which can forfeit interest or worse depending on the state
- Ignoring the AFR on a large zero-interest family loan and discovering imputed interest at tax time
- Failing to record payments, so nobody can prove the balance either way
- Modifying terms verbally: every extension, holiday, or rate change belongs in a signed writing
- Losing the signed original, which is the instrument itself and matters if you ever need to enforce or transfer it
- Forgetting a release: when the loan is paid, mark the original 'Paid in Full', sign it, and give the borrower a copy
- Treating a real gift as a loan to save face: paper that no one intends to enforce creates tax and family problems in both directions
Frequently asked questions
Is a promissory note legally binding?
Yes. A written note stating the amount, the repayment terms, and signed by the borrower is an enforceable contract in every state. Courts enforce them routinely, including between family members, as long as the terms show a real loan rather than a gift.
Does a promissory note need to be notarized or witnessed?
No, the borrower's signature is enough to make it binding. Notarization is optional but recommended for large amounts because it removes any later dispute about who signed.
What interest rate can I charge on a private loan?
Anything from zero up to your state's usury limit, which varies by state and loan type. For family loans, charging at least the IRS Applicable Federal Rate avoids imputed-interest tax issues on larger amounts.
What happens if the borrower does not pay?
The default clause lets the lender accelerate the loan, demand the full balance in writing, and sue on the note, often in small claims court. The signed note is the core evidence; keep the original and a record of all payments.
Can the loan be repaid early?
Under this template, yes: the borrower may prepay at any time without penalty, and prepayments reduce interest going forward. If you want a prepayment penalty instead, that is a term to negotiate and add in writing before signing.
Can the lender sell or transfer the note?
Generally yes: promissory notes are transferable, and the new holder collects on the same terms. The borrower's obligations do not change, and the borrower should get written notice of where to send payments. If you want to prohibit transfer, add that restriction before signing.
What happens if the borrower dies before repaying?
The debt does not die with the borrower: it becomes a claim against the borrower's estate, filed with the executor or probate court within the state's deadline. Whether it is collectible depends on the estate's assets. A guarantor, if any, remains liable regardless.
Can a promissory note be secured by collateral?
Yes, notes are often paired with security: a vehicle title lien, a UCC-1 filing on equipment, or a deed of trust on real estate. The security piece is separate paperwork on top of the note. For anything beyond a simple title lien, a full loan agreement handles the collateral terms better.
How long do I have to sue on an unpaid note?
Each state sets a statute of limitations for written contracts, commonly 3 to 6 years and longer in some states, generally running from default or from each missed installment. A written acknowledgment or partial payment can restart the clock in many states, but do not rely on that: act while the claim is fresh.
If two people sign as borrowers, who owes what?
Both owe all of it. Joint and several liability means the lender can pursue either signer for the full balance, and the signers sort out contribution between themselves. This is exactly why co-signing is a serious commitment rather than a formality.