--- title: PostalForm mailing limits and provider routing description: PostalForm chooses an eligible print-mail route from the destination, sender, document page count, print mode, mailing service and enabled providers. These are the application's configured route limits, not a guarantee that every provider is available for every address. Validate the actual order before relying on a maximum. seotitle: "PostalForm mailing limits: pages, sheets and Certified Mail routing" seo-description: Understand PostalForm document limits, address-page counting, Certified Mail route eligibility, postcard requirements and how to validate the actual mailing. group: resources indexable: true nav: false schema: webpage eyebrow: Mailing specifications published: 2026-10-15 updated: 2026-10-15 path: /mailing-limits --- # PostalForm mailing limits and provider routing PostalForm chooses an eligible print-mail route from the destination, sender, document page count, print mode, mailing service and enabled providers. These are the application's configured route limits, not a guarantee that every provider is available for every address. Validate the actual order before relying on a maximum. ## How many pages can PostalForm mail? PostalForm checks the document against the selected provider and mailing service before checkout. The configured general routes include up to 199 single-sided or 398 double-sided document pages, but Certified Mail and international routes have separate limits. The generated address page, physical sheet count and final quote must be considered separately. ## Document pages, printed pages and physical sheets - **Document pages** are the pages in the submitted or generated document. Routing limits below use this count. - **Billable pages** include the address page when the selected route adds one. A one-page document can therefore have two billable pages. - **Physical sheets** depend on printing mode and how the provider inserts the address sheet. Duplex does not make a separate cover sheet disappear. - For First-Class letters, a one-page document normally adds an address page. Lob duplex letters use a separate cover sheet; other routes may place the document on its reverse. Use the [canonical pricing matrix](/pricing) for examples. - USPS First-Class, Certified Mail and Return Receipt are distinct choices. Return Receipt is an optional proof service; it does not increase the route's document capacity. ## Configured U.S. document limits | Route | General single-sided limit | General double-sided limit | Certified Mail limit | Scope | | ---------- | -------------------------- | -------------------------- | ------------------------------------------------- | ---------------------------------------------------------------------------------------- | | Lob | 59 document pages | 118 document pages | 59 single-sided / 118 double-sided | Eligible U.S. First-Class letters | | PostGrid | 199 document pages | 398 document pages | 6 single-sided / 12 double-sided | Separate Certified limits apply | | Click2Mail | 99 document pages | 198 document pages | No general consumer Certified route promised here | Eligible Priority / Rush Express mail; product availability depends on the checkout path | The claim that a Certified letter exceeding Lob's limit automatically switches to PostGrid's 199/398-page capacity is incorrect. Those are PostGrid's general limits; its configured Certified capacity is lower. If no eligible route supports the chosen document and service, validation rejects the combination. Do not split a legal packet or change a required mailing method merely to bypass a limit. Provider-specific enterprise or Projects products can have different supported services. Use that product's API and quote rather than transferring a limit or capability from another PostalForm checkout path. ## International mail and postcards | Capability | Main constraint | Reference | | --------------------------- | ---------------------------------------------------------------------------------------------- | ------------------------------------------------------- | | International document mail | Supported destination, return address, local format, file size and country-specific page limit | [International mailing](/delivery-times) | | PinGen Fast | Offered only for eligible destinations and documents | [Delivery options](/delivery-times) | | Postcard PDF | Exactly two pages with the selected bleed canvas | [Postcard PDF specifications](/postcard-pdf-guidelines) | | International Lob postcard | `4x6` size and U.S. return address | [Postcards](/postcards) | | Workflow form API | Published single-mailpiece form, active required fields and attachment limits | [Machine form schemas](/developers/forms) | Do not apply the general maximum to every international destination. PinGen page limits vary by country and its PDF size limit is 8 MB. The browser's 100 MB upload ceiling does not override a smaller provider limit. ## Validate before quoting or paying For a browser order, upload or generate the document and inspect its preview, addresses, available mailing services and total. For an agent, call `POST /api/machine/orders/validate` or `POST /api/machine/mpp/orders/validate` using the complete proposed order. A successful validation checks the proposed input; it does not pay for or send mail. Use the returned errors to fix the document or select an authorized alternative. After payment, retain the order ID for status retrieval. A provider handoff or postal acceptance event is not proof of delivery. ## Resources - [Canonical pricing matrix](/pricing) - [Pricing calculator and live validation example](/pricing-calculator) - [Machine order payloads](/agents) - [Postcard capabilities](/postcards) - [Machine form schemas](/developers/forms)