Estimate your postcard mailing cost — per-piece postage and total — by mail class, postcard size, and quantity. All figures are clearly-labeled estimates from public USPS prices; always verify current rates at usps.com.
Single-piece retail postcard postage. Best for small, addressed mailings; no permit required.
Size affects which rate you qualify for — see the eligibility note below.
Number of postcards you plan to mail.
Eligibility: The USPS First-Class postcard rate applies only to cards from 3.5×5 in up to 4.25×6 in. A 4×6 card qualifies.
Estimate only. Per-piece rates are taken from the current public USPS price list and are labeled as estimates. Commercial rates (Marketing Mail) vary by sortation, presort level, and entry point and require a permit and minimum volume; EDDM Retail uses a single flat per-piece rate. USPS rates change periodically — always confirm current pricing at usps.com before you budget. This tool estimates postage only — it does not include printing, design, mail-prep, permits, or sales tax.
These are the public USPS per-piece estimates this calculator uses. They are rounded, clearly-labeled estimates — your actual rate depends on size, weight, sortation, and entry method. Confirm the live figure at usps.com.
| Mail class | Est. per piece | Notes |
|---|---|---|
| First-Class Mail postcard | ~$0.56 | Single-piece retail postcard rate. Card must meet USPS postcard dimensions (about 3.5×5 in to 4.25×6 in). Oversized cards pay the letter or flat rate instead. |
| USPS Marketing Mail (commercial) | ~$0.20–$0.35 | Bulk commercial rate; requires a permit and minimum volume (typically 200+ pieces). Exact price depends on presort and automation. We estimate ~$0.30/pc. |
| EDDM Retail | ~$0.224 | Saturation mail to entire carrier routes — no list, no individual addresses. Flat per-piece rate; card must meet USPS flat dimensions (6×9 and 6×11 qualify). |
Sources / hedge: Rates above are summarized from the public USPS Notice 123 price list and USPS.com and presented as estimates. USPS adjusts prices periodically; the live figure at usps.com always governs.
USPS prices a postcard by its physical dimensions, not just by what you call it. The big jump happens when a card grows past the postcard window:
In short: 4×6 is the budget pick for small addressed drops, while 6×9 and 6×11 shine for saturation (EDDM) or high-volume commercial mailings where the bigger canvas earns its keep. These are general rules — weight and thickness can change eligibility, so confirm at usps.com.
Postage is only part of the job — you still have to design the card, print it, address it (or sort routes for EDDM), and get it to the Post Office. PostKnock rolls all of that into one per-piece price paid from your wallet: design in the in-app Design Studio (4×6, 6×9, 6×11), and we handle printing, USPS First-Class postage, and mailing. We also run EDDM-style saturation mailing the easy way — no bundling, no minimums, no contracts.
PostKnock’s all-in pricing (printing + First-Class postage) is about $1.05 per 4×6 card on the Free plan and $0.79 on Pro. That’s higher than raw USPS postage because it includes printing and fulfillment — plus QR-code scan tracking and the option to add a phone-call follow-up wave via the built-in Call Queue (Pro). Contacts come in by CSV: export your list from another system and import it — the import wizard auto-maps the columns. PostKnock does not integrate directly with your CRM or practice software, and it does not send email.
Start Free →The estimate is deliberately simple and transparent — you can check it on a napkin.
EDDM Retail uses one flat per-piece rate regardless of size, as long as the piece meets USPS flat dimensions. First-Class postcard postage applies only to cards within postcard dimensions; oversized cards fall to the letter or flat rate. All rates are estimates — confirm the current figure on usps.com before committing a budget.
Want to see whether the mailing pays for itself? Run our postcard marketing ROI calculator → or estimate a saturation drop with the EDDM cost estimator →
For a standard 4×6 card, the USPS First-Class single-piece postcard rate is currently about $0.56 per piece on the public price list. Bulk commercial USPS Marketing Mail can run roughly $0.20–$0.35 per piece with a permit and minimum volume, and EDDM Retail saturation mail is about $0.224 per piece. These are estimates — USPS rates change, so confirm the current figure at usps.com.
Yes. The First-Class postcard rate only applies to cards within USPS postcard dimensions (roughly 3.5×5 in up to 4.25×6 in), so a 4×6 card qualifies. A 6×9 card is too big for the postcard rate and, as addressed First-Class mail, pays the higher letter rate; a 6×11 card is typically priced as a flat. Both larger sizes still qualify for EDDM and for commercial Marketing Mail rates. Weight and thickness can also affect eligibility — verify at usps.com.
First-Class postcard postage is the simplest option: buy postage and mail to specific addresses, no permit needed, fastest delivery. USPS Marketing Mail is a bulk commercial class with lower per-piece cost, but it requires a permit, a minimum volume, and presorting, and delivers more slowly. EDDM (Every Door Direct Mail) saturates entire USPS carrier routes without a mailing list at a low flat per-piece rate, but you mail to every address on the route and handle bundling and drop-off yourself.
No — they are clearly-labeled estimates pulled from the public USPS price list. Actual postage depends on the exact size, weight, thickness, sortation level, and entry point of your mailing, and USPS adjusts prices periodically. Commercial Marketing Mail rates in particular vary widely by presort and automation. Always confirm the current price at usps.com before you budget.
Yes. PostKnock charges one all-in per-piece price paid from your wallet that includes printing and USPS First-Class postage — about $1.05 per 4×6 card on the Free plan and $0.79 on Pro. You design in the in-app Design Studio (4×6, 6×9, 6×11) and we print and mail it, including EDDM-style saturation drops. You also get QR-code scan tracking and, on Pro, can add a phone-call follow-up wave via the built-in Call Queue. To mail to a list, export it from your other software as a CSV and import it — PostKnock does not integrate directly with CRMs or practice software and does not send email.
Design your postcard, pick your list or your neighborhood, and let PostKnock print and mail it — postage included. Pay per piece from your wallet. No credit card to start.
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