Written by Acorn Sales Company, manufacturing stamps and seals since 1964 · Reviewed by Holly R, VP of Sales and Marketing at Acorn Sales, against the Minnesota Board of Architecture, Engineering, Land Surveying, Landscape Architecture, Geoscience, and Interior Design and Minn. Stat. § 326.12, subds. 2 and 3 on 21 September 2026 · Updated 21 September 2026
The seal is optional in Minnesota and the certification block is not, so the thing to buy is a text block rather than a circle. Minn. R. 1800.4300 provides that each person “may, upon licensure or certification, also obtain a seal,” and that a stamped seal “may be used on documents in addition to the signed and dated certification required under part 1800.4200.” Minn. R. 1800.4200, subp. 1 is the mandatory half, implementing Minn. Stat. § 326.12, subd. 3, which requires the signature to be accompanied by a certification that the signer is licensed or certified, by the certificate number and by the date.
Your wording differs from every other credential on this board by one word. Minn. R. 1800.4300 prescribes seven legends and six of them open with “licensed.” Yours reads “certified interior designer.” The certification sentence at Minn. R. 1800.4200, subp. 4 follows: “I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly Certified Interior Designer under the laws of the state of Minnesota.” And the number label tracks the credential, so the block reads Cert. No.
The optional seal, by contrast, is unprescribed in every physical respect. No dimension appears in Minn. Stat. § 326.12, subd. 2 or in Minn. R. 1800.4300, and the board publishes none, so size and shape are yours to choose. What the rule does fix is the legend. If you hold the Minnesota certificate, “certified interior designer” is yours to use. If you do not, leave that state-issued title off and put your own name, your firm name and any credential you actually hold, such as NCIDQ, on instead.
Minnesota interior designer seal requirements at a glance
| Requirement | Minnesota rule | Source |
|---|---|---|
| Seal required | No, but an optional seal is specified | Minn. Stat. § 326.12, subds. 2 and 3 |
| Required elements | On the optional seal: your name; On the optional seal: the legend “certified interior designer”; In the mandatory certification block: the prescribed interior designer certification sentence; In the block: your signature; In the block: your typed or printed name; In the block: the date; In the block: your certificate number, labeled Cert. No. | Minn. Stat. § 326.12, subds. 2 and 3 |
| Size and shape | Not addressed. No dimension appears in Minn. Stat. § 326.12, subd. 2 or in Minn. R. 1800.4300, and the board publishes none. Checked both provisions in full and Minn. R. 1800.4200 in full. There is no legally. | Minn. Stat. § 326.12, subd. 2 |
| Device allowed | For the optional seal the statute contemplates a regular seal with a rubber stamp facsimile permitted on tracings or on papers that a regular seal would damage. | Minn. Stat. § 326.12, subds. 2 and 3 |
| Signature and date | The certification, your signature, your typed or printed name, the date and your certificate number travel together. | Minn. Stat. § 326.12, subd. 3 |
| What must be sealed | Plans, drawings, specifications, reports and other documents prepared under Minn. Stat. §§ 326.02 to 326.15 that require a signature. | Minn. Stat. §§ 326.12, subd. 3 and 326.03 |
| Electronic seal | Minn. R. 1800.4200, subp. 1 permits the certification and signature to be “electronic, as defined by Minnesota Statutes, section 325L.02, paragraph (h); facsimile; or digital.” No technology, certificate authority or tamper-evidence test is named. | Minn. R. 1800.4200, subp. 1 |
| Renewal and lapse | A seal may be used during the life of the certificate if it remains unrevoked, unexpired and unsuspended, and it is unlawful to stamp or seal any document after the certificate has expired, been revoked or been suspended unless it has been renewed or reissued. | Minn. Stat. § 326.12, subd. 2 |
| Firm requirements | The board registers firms offering certified interior design services along with its other professions and issues a Firm Registration certificate. | Minn. Stat. ch. 319B |
| Regulator | The Minnesota Board of Architecture, Engineering, Land Surveying, Landscape Architecture, Geoscience, and Interior Design | Minn. Stat. §§ 326.02, 326.03 and 326.12, with Minn. R. 1800.4200 and 1800.4300, from the Minnesota Office of the Revisor of Statutes, and the board’s firm licensure information. The certified interior designer is one of seven credentials under the same two rules and is the only one whose legend and number label do not use the word licensed. |
Is a seal required in Minnesota?
Minnesota certifies interior designers and does not require them to own or use a seal. Minn. R. 1800.4300 provides that each person “may, upon licensure or certification, also obtain a seal,” and that a stamped seal “may be used on documents in addition to the signed and dated certification required under part 1800.4200.” The certification is what is mandatory: Minn. R. 1800.4200, subp. 1 makes the certification and signature on documents that require a signature mandatory, implementing Minn. Stat. § 326.12, subd. 3, which requires the signature to be accompanied by a certification that the signer is licensed or certified, by the certificate number and by the date the signature was affixed.
What must appear on the seal
- On the optional seal: your name
- On the optional seal: the legend “certified interior designer”
- In the mandatory certification block: the prescribed interior designer certification sentence
- In the block: your signature
- In the block: your typed or printed name
- In the block: the date
- In the block: your certificate number, labeled Cert. No.
Minn. R. 1800.4300 prescribes seven legends word for word and yours is “certified interior designer,” the only one of the seven that does not begin with the word licensed. The certification sentence in Minn. R. 1800.4200, subp. 4 tracks that: “I hereby certify that this plan, specification, or report was prepared by me or under my direct supervision and that I am a duly Certified Interior Designer under the laws of the state of Minnesota.” And the number label follows the credential, so the block reads Cert. No. rather than Lic. No. The optional seal carries no number at all.
Size and shape
Not addressed. No dimension appears in Minn. Stat. § 326.12, subd. 2 or in Minn. R. 1800.4300, and the board publishes none. Checked both provisions in full and Minn. R. 1800.4200 in full. There is no legally required Minnesota interior designer seal size or shape, because there is no legally required seal.
Embosser, rubber stamp or digital
For the optional seal the statute contemplates a regular seal with a rubber stamp facsimile permitted on tracings or on papers that a regular seal would damage. For the mandatory certification, Minn. R. 1800.4200, subp. 1 allows electronic, facsimile or digital form, and Minn. Stat. § 326.12, subd. 3 gives a stamp or printed signature the force of an actual signature if it accurately depicts one. A certification block stamp is the right purchase.
Signing and dating
The certification, your signature, your typed or printed name, the date and your certificate number travel together. Placement is fixed: the certification and signature “must appear on all pages of plans and drawings that must be signed, but only on the first page of specifications, plats, reports, or other documents that must be signed.” Nothing requires signing across a seal, since the seal is optional. The certification is permanent once applied and “must not be removed at a later date for any reason.”
Certified, not licensed, and the whole stamp changes because of it
Minnesota is one of the few states that gives interior designers a place on the design-professions board, and it gives them the same regime as architects and engineers with one word changed throughout. Minn. R. 1800.4300 lists seven prescribed legends and six of them open with the word licensed. Yours is “certified interior designer.” The certification sentence in Minn. R. 1800.4200, subp. 4 follows suit with “a duly Certified Interior Designer,” and the number in the block is a certificate number, so it is labeled Cert. No.
That is three separate places a supplier can get it wrong from a single careless template, and the fix is to specify all three when you order rather than to proofread one.
The deeper Minnesota point applies to you as much as to engineers: the seal is optional and the sentence is not. Minn. R. 1800.4300 says you may obtain a seal. Minn. R. 1800.4200, subp. 1 says the certification and signature are mandatory. So the thing to buy is a text block, not a circle, and it goes on every page of plans and drawings but only on the first page of specifications and reports.
Once applied it cannot be undone. Subpart 5 provides that the signature “becomes a permanent part of that document and must not be removed at a later date for any reason.”
Which documents must be sealed
Plans, drawings, specifications, reports and other documents prepared under Minn. Stat. §§ 326.02 to 326.15 that require a signature. The statutory carve-out is broad: the requirement does not apply to documents “of an intraoffice or intracompany nature or that are considered to be drafts or of a preliminary, schematic, or design development nature by licensed or certified individuals who would normally be responsible for their preparation.” Work that crosses into architecture or engineering remains subject to the practice provisions of Minn. Stat. ch. 326 and has to be certified by the licensee who holds the relevant credential.
Electronic and digital seals
Minn. R. 1800.4200, subp. 1 permits the certification and signature to be “electronic, as defined by Minnesota Statutes, section 325L.02, paragraph (h); facsimile; or digital.” No technology, certificate authority or tamper-evidence test is named. The statutory limit is that a stamp, printed signature or electronically created signature carries the force of an actual signature only “if it creates an accurate depiction of the licensed or certified professional’s actual signature.”
Renewal, lapse and retirement
A seal may be used during the life of the certificate if it remains unrevoked, unexpired and unsuspended, and it is unlawful to stamp or seal any document after the certificate has expired, been revoked or been suspended unless it has been renewed or reissued. Certificates renew biennially and the certificate number does not change. Nothing requires the device to be surrendered or destroyed, and the certification already applied to a document is permanent.
Firm requirements
The board registers firms offering certified interior design services along with its other professions and issues a Firm Registration certificate. Professional firm status under Minn. Stat. ch. 319B is a separate election. No rule puts a firm registration number on a certified document, and the firm holds no seal; the certification in Minn. R. 1800.4200, subp. 4 is written in the first person and names you.
What to check before you order
Order a certification block stamp and specify three things in writing: the sentence must read “a duly Certified Interior Designer under the laws of the state of Minnesota,” the number line must read Cert. No. rather than Lic. No., and the object of the sentence is “this plan, specification, or report.” Add ruled lines for Signature, Typed or Printed Name, Date and Cert. No. Check the proof against Minn. R. 1800.4200, subp. 4 before approving it. If you also want the optional seal, it carries your name and the legend “certified interior designer” with no number and no required size. Keep the signature line open, because a printed signature counts only if it accurately depicts your own.
Browse interior designer stamps and seals.
- Make Your Mark: Minnesota Interior Designer Seal Embosser Tips
- Your Guide to Minnesota Interior Designer Stamp Purchase
Frequently asked questions
Does Minnesota require a certified interior designer to have a seal?
No. Minn. R. 1800.4300 says you may obtain a seal on certification, and that a stamped seal may be used “in addition to” the certification. What is mandatory is the certification, your signature, your typed or printed name, the date and your certificate number, under Minn. R. 1800.4200, subp. 1 and Minn. Stat. § 326.12, subd. 3. Plenty of Minnesota certified interior designers own no seal at all and are fully compliant.
What has to be in the Minnesota certification block?
Five things: the prescribed sentence, your signature, your typed or printed name, the date, and your certificate number labeled Cert. No. The sentence is set out word for word in Minn. R. 1800.4200, subp. 4 and names you as “a duly Certified Interior Designer under the laws of the state of Minnesota” over “this plan, specification, or report.” Order the block with ruled lines for Signature, Typed or Printed Name, Date and Cert. No., and check the proof against the rule text before approving it.
Where does the Minnesota certification block go on a set?
Placement is fixed by Minn. R. 1800.4200, subp. 3. The certification and signature “must appear on all pages of plans and drawings that must be signed, but only on the first page of specifications, plats, reports, or other documents that must be signed.” Nothing requires you to sign across a seal, since the seal is optional in the first place.
What goes on the optional Minnesota interior designer seal?
Your name and the legend “certified interior designer,” per Minn. R. 1800.4300. No number appears on it, because the certificate number lives in the certification block instead. That is the whole specification. Everything else about the device, including the diameter, the border and whether it is round at all, is unstated and therefore yours.
What size is a Minnesota certified interior designer seal?
Any size you like. No dimension appears in Minn. Stat. § 326.12, subd. 2, in Minn. R. 1800.4300 or in Minn. R. 1800.4200, and the board publishes none. There is no legally required Minnesota interior designer seal size or shape, because there is no legally required seal.
Rubber stamp or embosser in Minnesota?
For the optional seal, the statute contemplates a regular seal with a rubber stamp facsimile permitted on tracings or on papers that a regular seal would damage. For the mandatory certification, Minn. R. 1800.4200, subp. 1 allows electronic, facsimile or digital form, and Minn. Stat. § 326.12, subd. 3 gives a stamp or printed signature the force of an actual signature if it accurately depicts one. A self-inking certification block stamp does the required job; the seal is the optional extra.
Which Minnesota documents need the certification?
Plans, drawings, specifications, reports and other documents prepared under Minn. Stat. §§ 326.02 to 326.15 that require a signature. The carve-out in Minn. R. 1800.4200, subp. 4a is wide: the requirement does not apply to documents “of an intraoffice or intracompany nature or that are considered to be drafts or of a preliminary, schematic, or design development nature.” Work that crosses into architecture or engineering stays subject to the practice provisions of Minn. Stat. ch. 326 and has to be certified by whoever holds that credential.
Can I sign Minnesota interior design documents electronically?
Yes. Minn. R. 1800.4200, subp. 1 permits the certification and signature to be “electronic, as defined by Minnesota Statutes, section 325L.02, paragraph (h); facsimile; or digital.” No technology, certificate authority or tamper-evidence test is named. The one statutory limit is that a stamp, printed signature or electronically created signature carries the force of an actual signature only “if it creates an accurate depiction of the licensed or certified professional’s actual signature,” so keep the signature line open on the block rather than having your signature engraved into it.
Can I take the certification off a document later?
No. Minn. R. 1800.4200, subp. 5 provides that the signature “becomes a permanent part of that document and must not be removed at a later date for any reason.” That is worth knowing before you certify a set rather than after.
What happens if my Minnesota certificate lapses?
A seal may be used during the life of the certificate while it remains unrevoked, unexpired and unsuspended, and Minn. Stat. § 326.12, subd. 2 makes it unlawful to stamp or seal any document after expiration, revocation or suspension unless the certificate has been renewed or reissued. Certificates renew biennially and the number does not change, so nothing has to be recut. There is no duty to surrender or destroy the device, and certifications already applied stay permanent.
Does my firm need to register with the Minnesota board?
The board registers firms offering certified interior design services alongside its other professions and issues a Firm Registration certificate; professional firm status under Minn. Stat. ch. 319B is a separate election. No rule puts a firm registration number on a certified document, and the firm holds no seal. The certification at Minn. R. 1800.4200, subp. 4 is written in the first person and names you.
