Informational Postcards: What They Are and How to Mail One

An informational postcard has one job: put a single, specific message in someone's hand without asking them to open anything. No envelope, no click, no login. That directness is why appointment reminders, rate-change notices, schedule changes, and program announcements still ship as postcards long after the same message started going out by email.

It is also the format where a quarter-inch of trim size decides whether you pay the USPS card rate or the letter rate. Get the dimensions right and postage stays low. Get them wrong and the same message costs more per piece for the life of the campaign.

What is an informational postcard?

An informational postcard is an unenclosed mail piece that delivers a single factual message, such as an appointment reminder, a policy or rate change, a closure notice, or an event announcement, rather than a sales offer. To mail at the USPS card rate it must be rectangular and measure at least 3.5 by 5 inches and no more than 4.25 by 6 inches, with paper between 0.007 and 0.016 inches thick. Anything larger, up to 6.125 by 11.5 inches, still mails, but it is priced as a letter rather than a card.

The size rules that set your postage

USPS does not price postcards by what you call them. It prices them by physical dimensions. There are three bands, and every informational postcard falls into exactly one of them.

Thickness matters as much as length and width. A card thinner than 0.007 inches or thicker than 0.016 inches falls out of the card category entirely. Those are USPS eligibility limits, not durability guidance, and missing either end costs you the rate. In practice that puts a 4 by 6 informational postcard on cover stock in the 14pt to 16pt range. Note that 16pt is 0.016 inches, which is exactly the ceiling, so 14pt is the safer target if your stock runs thick.

Two details catch people out. Corners may be square or rounded, but the piece has to stay rectangular, so a die-cut shape loses the card rate. Rounded corners are capped at a 0.125 inch radius; a larger radius than that reads as non-rectangular. And the 4.25 by 6 ceiling is a hard edge, not a guideline: a 5 by 7 card, which many people assume is a standard postcard, is over the limit and prices as a letter. Full specifications are published by USPS in Domestic Mail Manual 101.

If you want a bigger canvas, that is a legitimate choice, just make it deliberately. A 6 by 9 or 6 by 11 card gives you far more room for a map, a schedule table, or a list of covered services, and it stands out in the stack. You are simply buying that attention at the letter rate instead of the card rate.

2026 postage for informational postcards

The figures below are current USPS prices per USPS Notice 123, effective July 12, 2026. They are postage only. Printing, data work, and mail preparation are quoted separately.

The First-Class Mail Presort postcard Mixed rate is $0.495 per piece, and that is the tier most mailings land in unless your list is dense enough in a single area to sort tighter. A retail single-piece postcard stamp, by contrast, is $0.65. Presorting is what closes that gap, and it is why volume mailings go through a mail service provider rather than the retail counter.

Source: USPS Notice 123 Price List, effective July 12, 2026.

One caveat on the table above: the card-versus-letter penalty applies within a class, not across classes. USPS Marketing Mail letter, Mixed tier, is $0.467 per piece, which sits below the First-Class card rate, so a non-urgent oversize card at Marketing Mail can cost less than a card-size piece mailed First-Class. Size discipline saves money once the class is fixed.

Two rules decide which line applies to you. First-Class gets forwarded and returned if the address is bad and moves fastest, which is why anything time-sensitive goes First-Class. Marketing Mail is the cheaper choice when the message can wait about a week, and MPA quotes cards at the Marketing Mail letter rate. Note the minimums: presorted First-Class needs 500 pieces, and Marketing Mail needs 200. Since July 12, 2026, presorted letters and postcards may be combined to reach that 500-piece First-Class minimum, which helps if you are mailing both formats in the same drop.

For all-in budgeting that includes printing, data, and mail services alongside postage, see how much postcards cost and the current USPS postage rates for 2026.

What informational postcards actually get used for

The format earns its keep when the message is short, the timing matters, and you need it to land whether or not the recipient is paying attention to a screen.

Appointment and service reminders

A dated reminder is the single most common informational postcard we run. It carries one date, one time, one location, and one phone number. The reason it stays on paper is that it survives. A card on the refrigerator is still visible on the day it matters, while the same reminder in an inbox has usually been buried by newer mail.

Notices, rate changes, and required disclosures

When an organization has to tell people something, a postcard creates a clean, low-friction record of the notice. Rate adjustments, policy updates, service-area changes, and annual disclosures all fit. Because there is no envelope to open, the message is visible the moment the piece is handled, which is the practical argument for a card over an enclosed letter.

Schedule, closure, and location changes

Holiday hours, a route change, a temporary closure, a new address. These are pure logistics messages with a short shelf life, and they only work if they arrive before the change does. Plan backward from the effective date, not forward from the day the file is ready.

Event and program announcements

Open houses, registration windows, public meetings, seasonal programs. The card carries the date and the one action you want, and the detail lives at a URL or QR code. Resist the urge to reproduce the whole agenda on the card.

Writing one people actually read

A postcard is sorted into keep or discard almost immediately, usually while the recipient is still standing over a bin. Everything below follows from that.

Pick one message. If you find yourself writing "also," you have a second postcard, not a longer one. The most common failure we see in customer files is three announcements competing on one 4 by 6 card, none of which registers.

Split the work across the two sides. The address side is legally and physically constrained, so the non-address side carries the headline and the visual. Put the single most important fact, usually a date or a dollar figure, in the largest type on the card.

State the action plainly. "Call 863-687-6945 by October 3" outperforms "contact us for more information" because it names both the step and the deadline. If the action lives online, a short URL or a QR code beats a long link nobody will retype.

Write for someone who does not already know the context. Internal shorthand, program acronyms, and account terminology are invisible to you and opaque to the reader.

The address side has rules

The right half of the address side is reserved. The delivery address block, the barcode clear zone, and the postage area in the upper right, whether that is a stamp, a meter mark, or a permit imprint, all live there, and artwork that intrudes on any of them will bounce at mail entry. That leaves the left half for a return address and any short secondary message.

Leave the bottom right corner alone entirely. That is the barcode clear zone, and it must stay free of graphics and dark background color so the USPS automation can read it.

Getting the print file right

Most delays on informational postcard jobs are file problems, not press problems, and they are all avoidable.

Build the artwork at final trim size with 0.125 inch of bleed on every edge, and keep live text at least 0.125 inch inside the trim. Supply images at 300 dpi at final size, not upscaled from a web asset. Set the document to CMYK, because RGB colors shift when they convert on press, and a brand blue that goes purple is the most common surprise in a first proof.

Send a print-ready PDF with fonts embedded or outlined. If you want to check a file before you send it, MPA's free file check tool flags bleed, resolution, and color-space problems in a few seconds. Pre-built layouts at the right trim sizes, with the address block and clear zones already marked, are on the direct mail design templates page. Size and stock options for each format are listed on the postcard printing page.

Stock and coating

Stock choice is a postage decision before it is an aesthetic one. On a 4 by 6 card, 14pt cover sits inside the 0.007 to 0.016 inch window with margin, feeds cleanly through addressing equipment, and arrives without the soft corners that make a piece look like junk. Text-weight paper is cheaper, but it falls under the thickness minimum and will not qualify for the card rate.

Coating is a tradeoff. A gloss or UV coating makes photography look better and resists scuffing through the mail stream, but you cannot reliably write on it, which matters if the recipient is meant to note a date or the card carries a handwritten touch. Matte and uncoated stocks take ink and pen, and they read as more official, which suits notices and disclosures. A common split is gloss on the image side and uncoated on the address side.

One caution on dark backgrounds: a heavy solid ink coverage across the address side interferes with barcode reading and shows every handling mark. Keep the address side light.

Choosing how to mail it: EDDM or a targeted list

The choice sets your postage line and decides whether the job needs list work at all, so make it before you size the card.

EDDM is the right tool when the message applies to everyone in an area, such as a road closure, a new location, or a service-area announcement. There is no list to buy or maintain, and you can plan routes yourself with the free EDDM route planner before you commit to a quantity. Our EDDM services page covers the drop logistics.

A targeted list is the right tool when the message belongs to specific people, which covers nearly all reminder and notice mail. Run the list through CASS validation and NCOA move update before it goes to press. Both are cheap relative to postage, and every undeliverable piece is postage plus printing spent on nobody.

Working backward from the in-home date

The mistake that costs the most on informational postcard jobs is treating the mail date as the deadline. The deadline is the in-home date, and mail takes time to get there.

Build the schedule in reverse. Decide the date the card needs to be in hand, then subtract delivery time, then subtract mail preparation, then subtract print and proof. USPS publishes a service standard of one to five days for First-Class Mail. Marketing Mail runs longer and is less predictable, which is the real reason dated messages go First-Class even though the postage is higher.

Ahead of that, allow time for the data work. Address standardization, CASS validation, NCOA move update, deduplication, and presorting all happen before a single sheet prints, and a list that arrives with inconsistent fields takes longer than a clean one. Proofing and any corrections sit ahead of that again.

For a dated notice, a working rule is to have the final file and the final list in hand roughly two weeks before the in-home date. That is not press time, which is short. It is the accumulated cost of getting a list clean, a proof approved, and a mailing inducted on a day USPS is accepting it.

One scheduling note specific to notices: if the card announces something that takes effect on a date, aim to land it well before that date, not on it. A closure notice that arrives the morning of the closure has technically been mailed and has practically failed.

Matching the format to the message

Format follows content. A one-line reminder does not need a 6 by 11 card, and a schedule with twelve rows will not fit on a 4 by 6.

The pattern is consistent: stay at or under 4.25 by 6 inches when the message is short enough to fit, and step up only when the content genuinely needs the space. Paying the letter rate to hold a single sentence is the most common avoidable cost on these jobs.

What tends to go wrong

Four failures account for most of the reprints and delays we see on informational postcard work.

The card is a quarter-inch too big. Someone designs to 4.5 by 6 because it looked better in the layout, and the whole run prices as a letter. Confirm the trim before the design is approved, not after.

The address side is crowded. Artwork, a logo, or a dark background creeps into the barcode clear zone, and the mailing gets held at entry until it is fixed. That is a reprint, not an edit.

The list was never cleaned. Undeliverable pieces are the most expensive thing in a mailing, because you pay full postage and full printing to reach nobody. CASS validation and NCOA move update cost a fraction of the postage they protect.

The mail date was set from the wrong end. The schedule was built forward from when the file would be ready instead of backward from when the card had to arrive, and a dated notice landed after its own effective date.

Where MPA fits

We have run mail out of a single Lakeland, Florida production facility for 35 years, for more than 700 lifetime business customers, and we mail to all 50 states. Printing, addressing, and mail preparation are all handled by our own team. We presort in-house and induct our own mail directly at the BMEU, which is what keeps the presort tiers above reachable on a real job.

For an informational postcard that means one point of contact from file to mail date, and a quote that separates printing, data, mail services, and postage so you can see what each part costs. Send a print-ready file, or ask us for the template for your trim size before you build it. Our mailing services page covers the full process.

Frequently asked questions

What size is an informational postcard?

To mail at the USPS card rate, between 3.5 by 5 inches and 4.25 by 6 inches, on stock 0.007 to 0.016 inches thick. Larger cards up to 6.125 by 11.5 inches mail normally but are priced as letters.

How much does it cost to mail an informational postcard?

Postage at the First-Class Mail Presort postcard Mixed tier is $0.495 per piece, or EDDM Retail at $0.260 per piece, per USPS Notice 123 effective July 12, 2026. Printing, data work, and mail preparation are quoted separately from postage.

Is a 5 by 7 card a postcard?

Not for postage purposes. At 5 by 7 inches it exceeds the 4.25 by 6 inch card maximum, so USPS prices it as a letter even though everyone calls it a postcard.

Should an informational postcard go First-Class or Marketing Mail?

Use First-Class when the message is dated, because it moves fastest and gets forwarded or returned on a bad address. Use Marketing Mail when the message can wait about a week and you want the lower rate.

Do I need a mailing list?

Only for targeted mail. EDDM delivers to every address on the carrier routes you pick with no list at all, which suits area-wide notices. Anything addressed to named recipients needs a CASS-validated list.

How long does an informational postcard take from file to mailbox?

Plan on roughly two weeks from final file and final list to the in-home date. Press time is short; the schedule is mostly data work, proofing, and USPS transit, for which the published First-Class Mail service standard is one to five days.

What paper thickness qualifies for the card rate?

Between 0.007 and 0.016 inches. A 14pt cover stock sits inside that window with margin; 16pt is 0.016 inches, exactly at the ceiling. Text-weight paper falls under the minimum and loses the card rate.

Can you help me get the artwork print-ready?

Yes, on request. Most customers send a print-ready PDF, or start from a free template on the direct mail design templates page and run it through the free file check. If you need help getting the file ready, mention it when you request a quote and we will scope it with the job.

Ready to mail

Send us the trim size, the quantity, and whether you are mailing to a list or to carrier routes, and we will come back with an itemized quote that separates printing, data, mail services, and postage. Call 863-687-6945 or request a quote online.