How to sign as power of attorney: formats, samples and rules

A power of attorney lets you act for someone else, but only if you sign in a way that shows you are doing exactly that. Get the format wrong and a bank, a title company or a hospital can refuse the document, even when your authority is beyond question.

Principal

The person who granted the power of attorney. They are the one whose affairs you are handling and whose name goes on the document as the party being bound.

Attorney-in-fact (or agent)

You. The person authorised to act under the POA. “Attorney-in-fact” is the usual term on a signature line and does not mean lawyer. Some documents use “agent” or “POA” instead, and both are generally accepted.

Durable power of attorney

A POA that stays in force after the principal loses mental capacity. A non-durable POA ends at that point, which is exactly when families usually need it, so most POAs written for incapacity planning are durable.

How to sign as power of attorney

There are two accepted orders, and both say the same thing:

1. Principal first: Jane Smith by John Doe, attorney-in-fact
2. Agent first: John Doe, attorney-in-fact for Jane Smith

Whichever you use, three elements have to be visible:

• Your own signature, in your own hand
• The principal’s name, so it is clear who is bound
• Your capacity, the words that say you signed under a power of attorney

Leave any one of them out and you create a problem. Sign only your name and the document appears to bind you personally. Sign only the principal’s name and it looks like a forgery. Sign both without naming your capacity and a reader cannot tell what authority you claim.

Sample formats by document type

How to sign a check as power of attorney

Checks are where most people run into trouble, because banks apply their own rules on top of the law.

Write the principal’s name, then “by”, then your signature, then “POA” or “attorney-in-fact” on the signature line. Keep it inside the line so the whole notation is legible on the scanned image.

Three things make this go smoothly:

• File the POA with the bank first. Most banks want the original or a certified copy on record before they will honour a POA signature, and many want it reviewed by their legal department. Doing this in advance, rather than at the counter with a cheque in hand, saves a rejected transaction.
• Ask whether the bank has its own form. Many institutions have an in-house POA or agent authorisation that they prefer, or require, alongside the general document.
• Expect scrutiny on large amounts. Banks flag POA signatures as a fraud risk, which is reasonable, and higher-value items get a closer look.

If the bank refuses, ask specifically what is missing. In practice it is usually that the POA is not on file, that it is not durable and the principal’s capacity is in question, or that the wording of the POA does not clearly cover banking.

Common mistakes that get a signature rejected

• Signing the principal’s name. The most common error and the most serious one. Even with permission, reproducing someone’s signature is forgery. The whole point of the POA format is to show that an agent signed.
• Signing only your own name with nothing else. The document then reads as your personal commitment, and you can find yourself liable for it.
• Leaving out the capacity. “Jane Smith by John Doe” without “attorney-in-fact” or “POA” is ambiguous.
• Using a POA that has already ended. See the section below. An agent who signs after the authority lapses can be personally liable.
• Assuming a general POA covers everything. Real estate, tax filings and gifts often need specific authority spelled out in the document. A general grant is frequently not enough.
• Not having the POA available. Counterparties routinely want to see it. Carry a copy, and know whether yours needs to be recorded, as real estate transactions usually require.

When the authority ends

A power of attorney is not permanent, and signing after it ends is a real risk.

• The principal dies. The POA ends immediately, with no grace period. From that moment the executor or personal representative of the estate takes over, and an agent has no authority at all. This catches people out with cheques in particular: an agent cannot sign a cheque for a principal who has died, even one written before the death.
• The principal revokes it. They may do so at any time while they have capacity.
• The principal loses capacity and the POA is not durable. A non-durable POA lapses exactly when it was most likely to be needed.
• The stated end date or purpose arrives. Limited and springing POAs are written to expire.
• A court appoints a guardian or conservator. Depending on the jurisdiction and the court’s order, this can supersede the POA.

Can someone with dementia sign a power of attorney?

Only if they still have the capacity to understand what they are signing at the moment they sign. Capacity is assessed at that point in time, not by diagnosis. An early dementia diagnosis does not automatically remove it, and there are often lucid periods in which a valid POA can be executed.

That said, this is exactly the situation where documentation matters. A contemporaneous note from a physician on capacity, and independent witnesses, make the document far harder to challenge later. Once capacity is genuinely gone, a POA can no longer be created, and the family’s route is guardianship or conservatorship through a court, which is slower and more expensive. That is the argument for putting a durable POA in place early.

How do I sign as power of attorney for my mother?

The same way as for anyone else: [Mother's name] by [your signature], attorney-in-fact. The family relationship gives you no authority on its own, and it changes nothing about the format. Being someone’s child, spouse or next of kin does not let you sign for them. The POA document does.

Power of attorney and other ways of signing for someone

A POA is one option among several, and it is the heaviest. For everyday business documents, lighter markers usually fit better:

• p.p. (per procurationem) for signing as a proxy on letters and correspondence
• For and on behalf of when you act with a company’s general permission
• By when an officer binds a company they work for

Our guide to signing on behalf of others covers those in full, including which one to reach for in which situation.

Inside a company, the equivalent of a POA is a documented signing authority: who may commit the organisation, to what value, and for which document types. That is a policy question rather than a legal instrument, and it is covered in authority signatory: who, why and how to authorize .

Signing as power of attorney on electronic documents

Nothing about a POA requires paper. In most jurisdictions an electronic signature carries the same weight as a wet one, and the same signature format applies: your own signature, the principal’s name, your capacity.

Two practical points specific to electronic signing:

Put the capacity in the document, not in the image. Type “Jane Smith by John Doe, attorney-in-fact” as text next to or beneath the signature field . Text stays searchable and auditable, and it will not be carried into an unrelated document by accident.

Keep the POA with the signed file. Attach a copy as an exhibit or store it alongside the executed document. When someone questions the signature years later, the authority and the signature need to be findable together.

Some counterparties, notaries and land registries still insist on wet signatures for POA-based execution. Check before you send, because discovering it after signing means starting again.

Make the signature image

For an electronic document you need your signature as an image with a transparent background. Draw it, type your name and choose a style, or photograph a signature on paper and let the tool remove the page. Everything runs in your browser and nothing is uploaded.

Remember that the image is only your own signature. The “by” and the “attorney-in-fact” wording belongs in the document, as text, next to the field.

Conclusion

Signing under a power of attorney is not complicated, but it is unforgiving about form. Sign your own name, name the principal, state your capacity, and make sure the authority is still live and broad enough to cover what you are signing. When a document is refused, it is almost always one of those four that is missing.

This article is general information, not legal advice. Power of attorney rules vary considerably between jurisdictions, and between US states in particular. For high-value transactions, real estate and anything involving a court, take advice on the document you actually hold.

Related reading:

• How to sign on behalf of others , for p.p. and the other markers
• Authority signatory , for signing authority inside a company
• Contract signatory , for who may sign a contract at all
• Free signature generator , to make the image

Frequently Asked Questions (FAQ)

• How do you sign as power of attorney?

  Sign your own name and show the capacity you are signing in. The standard format is '[Principal's name] by [your signature], attorney-in-fact'. The reversed form, '[your signature], attorney-in-fact for [principal's name]', is equally acceptable. Never sign the principal's own name.

• Can I just sign the principal's name if they gave me permission?

  No. Reproducing someone else's signature is forgery regardless of permission, and it defeats the purpose of a power of attorney, which is to make it visible that an agent signed. Always use your own signature with the capacity noted next to it.

• How do I sign a check as power of attorney?

  Write the principal's name, then 'by', then your signature, then 'POA' or 'attorney-in-fact', all on the signature line. File the power of attorney with the bank in advance, because most banks will not honour the signature until the document is on record and reviewed.

• Can a power of attorney sign checks after the principal dies?

  No. A power of attorney ends the moment the principal dies, with no grace period. Authority passes to the executor or personal representative of the estate. Signing after that point can make the agent personally liable.

• How do I sign as power of attorney for my mother?

  Exactly as for anyone else: '[Her name] by [your signature], attorney-in-fact'. Being her child gives you no authority on its own. The power of attorney document is what does, and the format does not change because you are family.

• Can a person with dementia sign a power of attorney?

  Yes, if they have capacity to understand the document at the moment they sign it. Capacity is assessed at that moment, not from a diagnosis, and early dementia does not automatically remove it. A physician's note on capacity and independent witnesses make the document much harder to challenge later.

• What does attorney-in-fact mean?

  It is the person authorised to act under a power of attorney. It does not mean lawyer. 'Agent' and 'POA' are commonly used on signature lines instead, and are generally accepted.

• Does a general power of attorney cover everything?

  Often not. Real estate transactions, tax filings, gifts and changes to beneficiaries usually need that authority spelled out specifically in the document. Read the grant before assuming it covers the transaction in front of you.

• Can I sign as power of attorney electronically?

  In most jurisdictions yes, with the same format as on paper. Put the 'by' and 'attorney-in-fact' wording in the document as text rather than inside the signature image, and keep a copy of the power of attorney stored with the signed file. Some notaries and land registries still require wet signatures, so check before sending.

• What happens if I sign wrongly as power of attorney?

  The likeliest outcome is that the document is rejected and you sign again. The more serious risk is personal liability: signing only your own name can bind you personally, and signing after the authority has ended leaves you exposed. If a signature is refused, ask what specifically is missing before resigning.