To write an affidavit, you set out your identity and competence, swear or affirm that what follows is true, state the facts in numbered first-person paragraphs based on your own knowledge, and sign the document in front of a notary public. The format is predictable, and courts expect you to follow it. What matters just as much as the format is the content: everything in an affidavit is treated as sworn testimony, so a careless sentence can sink your case or expose you to perjury charges carrying up to five years in federal prison.
The Parts of an Affidavit
Judges and clerks expect a standard structure. Deviating from it won’t always void the document, but it invites objections and delays. In order, an affidavit contains:
- A title identifying the person swearing, such as “Affidavit of Jane Smith.”
- A caption with the court name, case number, and party names, if the affidavit supports a lawsuit. Affidavits that aren’t tied to a case (an affidavit of heirship, for example) skip this.
- Your full legal name, address, and a statement that you are over 18, of sound mind, and competent to testify.
- An oath clause, typically phrased: “I, [Name], being duly sworn, depose and state as follows.”
- Numbered factual paragraphs, each covering a single fact or a tightly related group of facts.
- A signature line and the date you sign.
- A jurat, where the notary certifies that you took the oath and signed in their presence, then adds their signature, printed name, seal, and commission expiration date.
Federal court rules require any affidavit used in a case to be based on personal knowledge, to set out facts that would be admissible as evidence, and to show the signer is competent to testify about those facts.1Cornell Law School Legal Information Institute. Federal Rules of Civil Procedure Rule 56 – Summary Judgment Those three requirements are a reliable checklist for any affidavit, in any setting.
A Template You Can Adapt
Replace bracketed items with your own information, and add or remove numbered paragraphs as needed.
AFFIDAVIT OF [FULL LEGAL NAME]
[COURT NAME]
[CASE NAME], Case No. [CASE NUMBER]
(Omit the caption above if the affidavit is not for a court case.)
STATE OF [STATE]
COUNTY OF [COUNTY]
I, [Full Legal Name], being duly sworn, depose and state as follows:
1. I am over 18 years of age, of sound mind, and competent to make this affidavit. The facts stated here are based on my personal knowledge.
2. [State your first fact. Example: “I reside at 123 Main Street, Springfield, Illinois, and have lived at this address since March 2019.”]
3. [State your next fact. Keep each paragraph focused on one point.]
4. [Continue numbering each new fact or event.]
5. [If attaching documents, reference them. Example: “A true and correct copy of the signed lease agreement is attached as Exhibit A.”]
I declare under penalty of perjury that the foregoing is true and correct.
___________________________
[Printed Name]
[Signature]
Date: _______________
JURAT
Subscribed and sworn to (or affirmed) before me this ___ day of __________, 20___.
___________________________
Notary Public
My Commission Expires: _______________
[Notary Seal]
Writing the Factual Paragraphs
This is where most affidavits go wrong. Judges have little patience for vague statements, secondhand information, or arguments dressed up as facts. A few ground rules will keep yours admissible.
Write only what you personally witnessed or did. Federal Rule of Evidence 602 requires a witness to have personal knowledge of the matter.2Cornell Law School Legal Information Institute. Federal Rules of Evidence Rule 602 – Need for Personal Knowledge If you didn’t see it, hear it, or do it yourself, it doesn’t belong in your affidavit. “My neighbor told me the fence was moved” is hearsay. “I measured the fence line on June 3 and found it two feet past the property marker” is personal knowledge.
Use first person and be specific. Every statement should begin with “I” and include concrete details: dates, amounts, locations, names. “I saw the defendant’s car” is weak. “On April 12, 2025, at approximately 3:00 p.m., I saw a blue Ford F-150 with license plate ABC-1234 parked in the loading zone at 500 Oak Avenue” gives the court something it can actually work with.
Keep opinions out. An affidavit is not the place to argue your case or characterize behavior. “The landlord was negligent” is a legal conclusion for the judge to reach. “The landlord did not repair the broken railing after I reported it in writing on January 5” is a fact.
Attach exhibits when documents matter. If your affidavit references a contract, photograph, receipt, or letter, attach a labeled copy (Exhibit A, Exhibit B, and so on) and identify it in the body: “A true and correct copy of the email dated March 10, 2025, is attached as Exhibit B.” That ties the document to your sworn statement and makes it part of the record.
Put facts in a logical order. Chronological order works for most affidavits. Start with who you are and why you know what you know, then walk through the events in sequence.
Signing: Notary, Oath, or Unsworn Declaration
A traditional affidavit requires a notary public to witness your signature and administer the oath. Do not sign the document before you arrive. The notary must watch you sign it.
Bring a government-issued photo ID. The notary will verify your identity, ask you to swear or affirm that the statements are true, watch you sign, and complete the jurat with their signature, printed name, commission expiration date, and seal. Notary fees are set by state statute in most states and typically run $2 to $15 per signature. Banks, shipping stores, law offices, and courthouses often have notaries available, and some public libraries offer the service for free. As of early 2025, more than 45 states and the District of Columbia also allow remote online notarization by video call, which is useful if you’re homebound or on a tight deadline, though fees tend to be higher, often $25 or more.
Oath or Affirmation
When the notary administers the oath, you’ll be asked whether you swear or affirm. Both carry exactly the same legal weight.3eCFR. 22 CFR 92.18 – Oaths and Affirmations Defined An oath invokes a sense of responsibility to God; an affirmation is a secular alternative for anyone with conscientious objections. The notary should offer you the choice. If they only offer an oath and you’d rather affirm, say so. No notary can force a religious oath, and no court treats an affirmed affidavit differently.
Skipping the Notary With an Unsworn Declaration
Federal law lets you skip the notary entirely in many situations. Under 28 U.S.C. ยง 1746, an unsworn declaration signed “under penalty of perjury” carries the same legal force as a notarized affidavit for most federal matters.4Office of the Law Revision Counsel. 28 USC 1746 – Unsworn Declarations Under Penalty of Perjury To use it, replace the jurat and notary block with this statement, just above your signature:
“I declare under penalty of perjury that the foregoing is true and correct. Executed on [date]. [Signature]”
If you sign outside the United States, add “under the laws of the United States of America” after “penalty of perjury.”4Office of the Law Revision Counsel. 28 USC 1746 – Unsworn Declarations Under Penalty of Perjury This option works for federal court filings and many federal agency submissions. Many states have adopted similar statutes for state proceedings, but the rules vary, so check your jurisdiction before skipping the notary for a state court matter. Depositions, oaths of office, and situations where the law specifically requires a particular official to administer the oath still require the traditional sworn process.
Mistakes That Get Affidavits Rejected
Courts strike or disregard affidavits more often than most people realize. The errors that cause the most trouble:
- Hearsay. Repeating what someone else told you has no evidentiary value if the court can’t cross-examine the original speaker.
- Legal conclusions instead of facts. Saying someone “breached the contract” or “committed fraud” tells the judge how to rule. Describe what happened and let the judge apply the law.
- Vague or conclusory statements. “The property was in bad condition” gives the court nothing to work with. Specify what was wrong, when you observed it, and how you know.
- Missing or defective notarization. If the notary forgot the commission expiration date, didn’t affix a required seal, or let you sign before arriving, the other side will challenge the affidavit.
- No basis for personal knowledge. Make clear why you know what you know. “I am the property manager for 500 Oak Avenue and have held that position since 2020” establishes your basis for testifying about conditions there.1Cornell Law School Legal Information Institute. Federal Rules of Civil Procedure Rule 56 – Summary Judgment
- Contradicting your prior testimony. If the affidavit says something different from a deposition or earlier filing, opposing counsel may use the inconsistency to impeach your credibility under Federal Rule of Evidence 607.
Redact Personal Information Before Filing
If your affidavit will be filed with a federal court, you are personally responsible for redacting sensitive information. Federal Rule of Civil Procedure 5.2 requires certain personal identifiers to be partially concealed in any court filing:5Cornell Law School Legal Information Institute. Federal Rules of Civil Procedure Rule 5.2 – Privacy Protection for Filings Made with the Court
- Social Security and taxpayer ID numbers: last four digits only.
- Birth dates: year only.
- Minors’ names: initials only.
- Financial account numbers: last four digits only.
The clerk will not review your filing for compliance. If you include a full Social Security number and file it, that number becomes part of the public record. Most state courts have similar redaction rules. If the court needs the unredacted information, you can file a complete version under seal alongside the redacted public copy.
The Penalty for Lying
Because an affidavit is sworn testimony, knowingly including false statements is perjury. Under federal law, perjury carries a maximum sentence of five years in prison, a fine, or both. The same statute applies to false statements in unsworn declarations made under penalty of perjury.6Office of the Law Revision Counsel. 18 USC 1621 – Perjury Generally State perjury statutes impose similar penalties, with prison terms commonly ranging from one to five years.
The practical fallout is often worse than the criminal risk. Judges who find a false statement in an affidavit tend to view everything else that party submitted with suspicion. Orders that rested on the affidavit can be vacated. People lose custody cases, see favorable settlements unwound, and get sanctioned by the court. If you’re not certain a fact is true, leave it out.
After You Sign
Make several copies once the affidavit is signed and notarized (or signed with the proper penalty-of-perjury language). Keep the original in a safe place. Courts and agencies generally want the original or a certified copy, so don’t surrender your only copy and hope to get it back.
If the affidavit supports a court case, file it with the clerk along with any related motion or petition, and serve copies on the other parties under the applicable rules. In federal cases, service is typically handled through the court’s electronic filing system, though some situations still require personal delivery or mailing. State court service rules vary; ask the clerk’s office if you’re unsure.
For a non-court purpose like an insurance claim, government agency submission, or real estate transaction, deliver the affidavit according to the requesting party’s instructions. Many institutions accept scanned copies of notarized affidavits, but some require originals, particularly for matters involving real property.