The short version
- An affidavit is a written statement of fact sworn or affirmed before someone authorised to administer an oath — usually a notary public. The oath is what makes it an affidavit rather than a letter.
- Do not sign it in advance. For a sworn statement the notary must watch you sign and administer the oath, which is the notarial act called a jurat.
- In federal matters, 28 U.S.C. § 1746 lets an unsworn declaration under penalty of perjury carry the same force as an affidavit, using prescribed wording and no notary at all.
- Only include what you personally saw, heard or did. Statements about what someone else told you, opinions and legal conclusions are the parts that get struck.
What an affidavit actually is
An affidavit is a written statement of fact, made voluntarily, and sworn or affirmed to be true before a person authorised to administer oaths — in ordinary life, a notary public. The person making it is the affiant or deponent.
It is used wherever a body needs a fact established but cannot have the person in front of them: family court applications, probate, insurance claims, immigration filings, small estate collections, name changes, identity or residence confirmations, and countless administrative processes. Because it functions as testimony, courts apply the rules of testimony to it — which is where most home-made affidavits run into trouble.
Affidavit or declaration?
A declaration is the same content without the notary. Instead of swearing before an official, you sign a statement declaring under penalty of perjury that what you have written is true.
In federal matters this is expressly permitted. Under 28 U.S.C. § 1746, an unsworn declaration made under penalty of perjury has the same force and effect as a sworn affidavit wherever federal law permits or requires a matter to be supported by an affidavit. The statute prescribes the wording, and it differs depending on where you sign: a declaration executed within the United States states that you declare under penalty of perjury that the foregoing is true and correct, with the date and signature; one executed abroad adds that it is under the laws of the United States of America. The statute does not reach depositions, oaths of office, or oaths required to be taken before a specified official other than a notary.
Two routes to the same evidential weight
Affidavit, sworn before a notary
- Oath or affirmation administered in person
- Signed in the notary's presence, never before
- Notary verifies identity and completes a jurat
- Accepted almost universally, including abroad
- Costs a fee and requires an appointment
Declaration under penalty of perjury
- No notary, no appointment, no fee
- Prescribed statutory wording, signed and dated
- Equal force in federal matters under 28 U.S.C. § 1746
- Same criminal exposure for a false statement
- Acceptance elsewhere depends on the recipient
Where a form, a court rule or a foreign body specifies an affidavit, use the notarised version — the declaration saves an hour and risks a rejection.
A declaration is the right instrument when you know the recipient accepts one. An affidavit is the safe default when you do not, or when the document is going somewhere formal enough to have its own form.
The parts of the document
The structure is conventional and worth following exactly, because the people receiving it are reading dozens and expect it in a particular order.
The order a receiving clerk expects to find it in
A sworn affidavit
Write short and specific. "On 14 March 2026 at approximately 7pm I saw the defendant's van parked outside number 12" is testimony. "The defendant has been persistently inconsiderate" is an opinion dressed as one, and it weakens every sentence around it.
Personal knowledge is the rule that gets affidavits struck
Federal Rule of Civil Procedure 56(c)(4) states the standard cleanly: an affidavit or declaration used to support or oppose a motion must be made on personal knowledge, set out facts that would be admissible in evidence, and show that the affiant is competent to testify to the matters stated. State rules echo it, and administrative bodies apply the same instinct even where no rule compels them to.
Three categories cause almost all of the damage.
| What people write | Why it fails | What to write instead |
|---|---|---|
| "My sister told me he had already moved out." | Hearsay — you are repeating someone else's statement for its truth | Have your sister swear her own affidavit, or state only what you observed |
| "He was clearly trying to intimidate me." | Opinion and inference, not observation | Describe the conduct: what was said, how loudly, how close, for how long |
| "The agreement is void for duress." | A legal conclusion — that is the decision-maker's job, not the witness's | Set out the facts about the circumstances and let the argument be made elsewhere |
| "I believe he has been paid in cash for years." | Belief and speculation; you cannot testify to what you suppose | State what you saw or handled, and say plainly if you do not know the rest |
Where you genuinely do not have first-hand knowledge, say so and say what your source is — some contexts permit information and belief, provided it is labelled as such. What is never acceptable is presenting second-hand material as though you witnessed it. An affidavit that mixes the two invites the whole document to be discounted rather than just the offending line.
Swearing it, in order
The procedure is short, and every step of it exists because a specific thing has gone wrong for someone before.
- 1
Finish the text — and do not sign it
Print the completed affidavit with the signature line blank. Signing in advance is the single most common reason people are turned away, because a sworn statement requires the notary to witness the signature.
- 2
Bring valid photo identification
A current government-issued ID is standard. The notary is certifying who signed, and cannot do that on your assurance.
- 3
Read it once more in front of the notary
You are about to swear it is true. This is the last moment at which correcting a date costs nothing.
- 4
Take the oath or affirmation out loud
The notary will ask whether you swear or affirm that the contents are true. You must answer audibly. A silent nod is not an oath, and a notary who accepts one has not performed the act.
- 5
Sign, in the notary's presence
Sign exactly as your name appears in the document and on your ID. Initial any handwritten correction, and have the notary initial it too.
- 6
Let the notary complete the jurat
They will fill in the venue, the date, your name, their signature, their commission details and their seal, and record the act in their journal where the state requires one.
- 7
Keep the executed original
File or serve copies and retain the original with the wet signature and seal. Some recipients will insist on the original; almost none will accept a document you have since altered.
Affidavit template
Read the full structure free — caption, venue, numbered statements of fact, exhibit references and the jurat block for the notary to complete. Check any prescribed form your recipient requires before using it.
Jurat, not acknowledgment
Notaries perform several distinct acts, and asking for the wrong one produces a document that looks notarised and is not sworn.
An acknowledgment certifies that the signer appeared, was identified, and acknowledged signing the document willingly. It involves no oath, and the document may already have been signed before arrival. It is the act used for deeds, powers of attorney and most contracts.
A jurat certifies that the signer appeared, was identified, signed in the notary's presence, and swore or affirmed that the contents are true. That oath is what creates the perjury exposure, and it is what an affidavit requires. The wording on the page differs accordingly: an acknowledgment reads "acknowledged before me", a jurat reads "subscribed and sworn to before me". If the block on your document says the former, it is not an affidavit — ask for the jurat.
Notarising remotely
Most US states now authorise remote online notarisation, in which the affiant and notary meet over live audio-video, identity is verified electronically and the notarisation is performed on an electronic document. Around forty states have permanent authority; several others operate under temporary or limited rules, and California is phasing implementation in over a period ending in 2030.
Two points decide whether it will work for you. The governing law is that of the state where the notary is commissioned, not where you are sitting. And authorisation to perform the act is not the same as acceptance of the result — some courts, registries and foreign authorities still require a traditional paper original with a physical seal. Check what your recipient will take before booking anything. The broader rules on when an electronic signature is and is not sufficient are covered in are electronic signatures legally binding.
The consequence of getting it wrong
A false affidavit is not a civil embarrassment. Under federal law, wilfully subscribing as true any material matter you do not believe to be true is perjury under 18 U.S.C. § 1621, and false material declarations before a court or grand jury fall under § 1623. Both are punishable by a fine, imprisonment of up to five years, or both. State perjury statutes carry their own penalties, and declarations made under penalty of perjury without a notary carry the same exposure as sworn ones — that is the entire point of the phrase.
Prosecution for an inaccurate affidavit in a routine matter is rare. The realistic risk is different and much more common: a decision-maker who catches one careless overstatement stops trusting the rest. In a family case, a probate application or an insurance claim, the affidavit is often the only thing standing in for you. Its usefulness is entirely a function of how carefully it stays inside what you actually know — which is also, conveniently, the version that is easiest to write.
Sources
- 28 U.S.C. § 1746 — unsworn declarations under penalty of perjury
- US Department of Justice — perjury cases under 28 U.S.C. § 1746
- Federal Rule of Civil Procedure 56 — affidavits and declarations
- 18 U.S.C. § 1621 — perjury generally
- California Lawyers Association — the difference between a jurat and an acknowledgement
- Remote online notarisation availability by state
General information, not legal advice. This guide explains how these documents and rules generally work. Law varies by jurisdiction and changes, and none of it is applied to your circumstances here. For anything consequential, consult a licensed attorney where you are.
Frequently asked
What is an affidavit?
A written statement of fact made voluntarily and sworn or affirmed to be true before a person authorised to administer oaths, usually a notary public. It functions as testimony given in writing, which is why it is written in the first person, limited to what the affiant personally knows, and backed by criminal penalties for a false statement.
Do I need a notary for an affidavit?
For an affidavit, yes — the oath must be administered by someone authorised to do so, and that is what distinguishes it from a letter. A declaration under penalty of perjury is the alternative: in federal matters, 28 U.S.C. § 1746 gives an unsworn declaration in the prescribed wording the same force as an affidavit, with no notary involved. Whether a declaration is accepted elsewhere depends on the receiving body.
What is the difference between a jurat and an acknowledgment?
An acknowledgment certifies that the signer appeared, was identified, and confirmed signing willingly — no oath is taken, and the document can have been signed beforehand. A jurat certifies that the signer appeared, signed in the notary's presence, and swore or affirmed the contents are true. An affidavit requires a jurat; an acknowledgment on a sworn statement means it was never actually sworn.
Can I sign an affidavit before seeing the notary?
No. A jurat requires the notary to witness the signature and administer the oath, so a document that arrives already signed will normally be refused or must be re-signed. Print it with the signature line blank, read it once more in front of the notary, answer the oath out loud, and sign then. Initial any handwritten correction and have the notary initial it too.
What should not go in an affidavit?
Anything you did not personally see, hear or do. That rules out repeating what someone else told you, opinions about motive or character, legal conclusions such as whether a contract was breached, and speculation about what you believe happened. Affidavits are held to the standards applied to testimony — personal knowledge, admissible facts, and competence to testify to them.