Letter Printing & Mailing Services
Professional letter printing, automated folding and inserting, and complete USPS mail prep — all under one roof in Salisbury, MD. Mail Movers handles everything from variable data personalization to USPS induction for businesses and nonprofits across Maryland, Delaware, and Virginia.
Why Direct Mail Letters Still Drive Results
In an era of email overload, a physical letter stands out. Letters carry authority, trust, and permanence that digital messages cannot replicate — especially for high-value communications like fundraising appeals, financial statements, and legal notices.
Sources: ANA/DMA Response Rate Report 2024; USPS Mail Moments Study; Data & Marketing Association.
USPS Letter Size Requirements
Official USPS dimensions that determine which postage class your letter qualifies for. Source: USPS Postal Explorer (pe.usps.com/businessmail101?ViewName=Letters).
| Dimension | Minimum | Maximum | Notes |
|---|---|---|---|
| Height | 3.5" | 6.125" | Height is the side perpendicular to the address |
| Length | 5" | 11.5" | Length is the side parallel to the address |
| Thickness | 0.007" | 0.25" | An index card is ~0.007" thick — use as a guide |
| Weight (First-Class) | Any | 3.5 oz | Over 3.5 oz moves to flat or parcel pricing |
| Weight (Marketing Mail) | Any | 3.5 oz | Over 3.5 oz moves to flat pricing |
| Aspect Ratio | 1.3:1 | 2.5:1 | Length ÷ Height must be between 1.3 and 2.5 |
Nonmachinable Surcharge: +$0.40/piece (July 2025)
First-Class letters with nonmachinable characteristics (square, rigid, unusually shaped, or aspect ratio outside 1.3–2.5) incur a $0.40 surcharge. Mail Movers checks every piece for nonmachinable characteristics before mailing.
Source: USPS Postal Explorer, Business Mail 101 — Sizes for Letters. Mail Movers verifies all piece dimensions before printing to ensure USPS compliance.
Letter Postage Rates — July 2025
All rates reflect the July 13, 2025 USPS rate increases. Mail Movers helps you qualify for the lowest available postage rate through presort, CASS certification, and USPS Full-Service compliance.
First-Class Mail
Fastest delivery (2–5 days), forwarding & return service included
Retail Rate
$0.78/oz (stamp)
Minimum Quantity
1 piece (no minimum)
Best For
Time-sensitive mail, invoices, legal notices, high-value correspondence
Marketing Mail (Standard)
Most Common7–14 day delivery, no forwarding or return service by default
Minimum Quantity
200 pieces minimum
Best For
Marketing campaigns, promotional letters, catalogs, high-volume mailings
Nonprofit Marketing Mail
Same as Marketing Mail but at significantly reduced rates for eligible nonprofits
Minimum Quantity
200 pieces minimum + USPS nonprofit authorization
Best For
Fundraising appeals, donor acknowledgments, membership renewals, event invitations
First-Class Presorted
First-Class speed and services with presort discounts for volume mailers
Minimum Quantity
500 pieces minimum
Best For
Invoices, statements, time-sensitive campaigns requiring forwarding/return
Postage rate note: Rates shown are planning estimates based on current USPS schedules and are subject to change. Actual postage depends on mail class, piece type, weight, sort level, and USPS effective date. Contact Mail Movers for a current quote specific to your campaign.
Source: July 2025 USPS Rate Increases, effective July 13, 2025. All-in cost includes printing, folding/inserting, addressing, presort, and USPS postage. Request a free quote for exact pricing.
Envelope Types & Standards
The right envelope affects open rates, postage class, and the perceived value of your letter. Mail Movers stocks all standard USPS-compliant envelope sizes.
#10 Standard Window
4-1/8" × 9-1/2"
The most common business envelope. Window shows recipient address through a clear panel — no separate addressing required. Ideal for invoices, statements, and business correspondence.
Best for: Invoices, statements, business letters
Window must align precisely with address block — we verify this before printing
#10 Closed-Face
4-1/8" × 9-1/2"
Address is printed directly on the envelope face. Gives a more personal, premium appearance than window envelopes. Typically achieves higher open rates for marketing mail because it looks like personal correspondence.
Best for: Fundraising appeals, marketing letters, VIP correspondence
Higher perceived value — recipients are more likely to open
#9 Reply Envelope
3-7/8" × 8-7/8"
Fits inside a #10 envelope for easy reply. Standard for fundraising appeals, subscription renewals, and any mailing that includes a return envelope. Can be pre-addressed and pre-stamped or left blank.
Best for: Fundraising appeals, subscription renewals, payment remittances
Pre-addressed reply envelopes significantly increase response rates
#6-3/4 Envelope
3-5/8" × 6-1/2"
Compact envelope for shorter letters and personal correspondence. Fits a single sheet folded in thirds. The smaller size creates a more intimate, personal feel — effective for high-touch donor communications.
Best for: Personal donor letters, thank-you notes, compact campaigns
Fits a single 8.5×11 sheet folded in thirds (C-fold)
6×9 Catalog Envelope
6" × 9"
For multi-page inserts, booklets, or documents that should not be folded. Opens on the short side. Ideal for sending brochures, multi-page letters, or packages with multiple inserts.
Best for: Multi-page inserts, booklets, complex packages
Mails at flat rate — higher postage than standard letter envelopes
9×12 Catalog Envelope
9" × 12"
For full-size documents that must remain flat. Ideal for legal documents, contracts, certificates, and any correspondence where folding would be inappropriate or damaging.
Best for: Legal documents, certificates, flat brochures, annual reports
Mails at flat rate — significantly higher postage than letter envelopes
Printing Features & Options
Standard Features
- Full-color or black-and-white printing
- Simplex (one-sided) or duplex (two-sided)
- 20# or 24# bond paper
- Automated folding (C-fold, Z-fold, half-fold)
- Automated inserting into envelopes
- CASS-certified addressing & Intelligent Mail barcoding
- USPS presort for maximum postage discounts
- Direct USPS induction — postal receipt provided
Premium Options
- Variable data printing (names, amounts, offers, images)
- Multi-piece inserting (reply envelope, brochure, insert card)
- Personalized ask amounts for fundraising appeals
- Custom QR codes with campaign tracking
- Informed Delivery digital campaign add-on
- MMScope omnichannel tracking (mail + calls + online)
- NCOA list processing before mailing
- Graphic design services for letter layout
Letter Campaigns by Industry
Letters are the preferred format for high-value, high-trust communications across virtually every industry. Here are the most common use cases and recommended approaches.
Fundraising Appeal Letters & Donor Communications
Nonprofit & Fundraising
Nonprofits rely on letters as their highest-ROI fundraising channel. A well-crafted appeal letter with a reply envelope and personalized ask amount consistently outperforms email for donor acquisition and retention. Mail Movers is experienced with USPS nonprofit postage authorization, which reduces postage to as low as $0.178/piece (July 2025 rates) — a significant savings on large-volume appeals.
Recommended Formats
- #10 closed-face (higher open rate)
- #9 reply envelope insert
- Variable data personalized ask amounts
Pro Tip
Include a reply envelope and a specific, personalized ask amount (based on prior giving history) to maximize response rate. Personalized ask amounts increase average gift size by 15–25%.
Direct Mail Letters vs. Email
Both channels have a place in a smart marketing mix. Here's how they compare across the metrics that matter most for business communication.
| Factor | Direct Mail Letter | |
|---|---|---|
| Average open rate | 80–90%Physical mail is opened and read | 20–30%Subject line must earn the open |
| Average response rate | 4.4% (house list)1.3% for prospect lists | 0.6–1.5%Click-through rate, not response |
| Consumer trust | High76% trust physical mail ads | ModeratePhishing concerns reduce trust |
| Shelf life | Days to weeksKept on desks, fridges, counters | Seconds to minutesBuried in inbox quickly |
| Deliverability | ~98%With CASS-certified addressing | 70–85%Spam filters reduce reach |
| Forwarding/return service | Yes (First-Class)Know when addresses are bad | Bounce notifications onlyNo physical forwarding |
| Personalization depth | Full variable dataName, amounts, images, QR codes | Merge tagsName and basic fields |
| Best use cases | High-value, high-trustFundraising, invoices, renewals, legal | High-frequency, low-costNewsletters, alerts, confirmations |
Sources: ANA/DMA Response Rate Report 2024; USPS Mail Moments Study; Data & Marketing Association.
How Letter Printing & Mailing Works with Mail Movers
From quote to USPS delivery — everything handled under one roof in Salisbury, MD.
Request a Quote
Contact Mail Movers with your letter specifications: page count, quantity, color or black-and-white, envelope type, and mailing list details. We'll provide a detailed quote within 24 hours covering printing, folding, inserting, postage, and USPS delivery.
Request a quote →Submit Your Content or Work With Our Team
Upload your letter content and mailing list, or work with our graphic design team to create a professional layout. We'll merge your variable data, check your file against USPS specifications, and send you a digital proof for approval.
Upload files →Approve Your Proof
Review your digital proof carefully, including all personalized variable data fields. Once you approve, we move immediately to production. Rush turnaround (1–2 business days) is available for urgent campaigns.
We Print, Fold, Insert & Mail
Our team prints your letters, folds and inserts them into envelopes, applies CASS-certified addresses and USPS Intelligent Mail barcodes, presorts for maximum postage discounts, and delivers directly to USPS. You receive a postal receipt confirming USPS induction.
Track Delivery and Response
Add USPS Informed Delivery or MMScope omnichannel tracking to monitor when your letters are delivered and track phone calls or online activity tied to your campaign.
Learn about MMScope →Design File Requirements
Submit print-ready files to avoid delays. Mail Movers reviews every file before printing — but following these specs ensures the fastest turnaround and best print quality.
| Specification | Requirement | Notes |
|---|---|---|
| File Format | PDF (preferred), DOCX, or INDD | Print-ready PDF preferred; Word files accepted for simple layouts |
| Resolution | 300 DPI minimum at final print size | 72 DPI screen resolution will print blurry |
| Color Mode | CMYK or black-and-white | RGB files will be converted; colors may shift slightly |
| Margins | 0.5" minimum on all sides | Keep all text and important elements inside margins |
| USPS Clear Zone | Bottom 5/8" of address side | Must be clear of all graphics; reserved for USPS barcode |
| Address Block | Upper right of envelope face | For closed-face envelopes; window envelopes use letter address block |
| Return Address | Upper left of envelope face | Required for First-Class mail to enable return service |
| Fonts | Embed all fonts or outline text | Missing fonts will cause substitution errors |
| Variable Data Fields | Delimited data file (CSV or Excel) | Column headers must match merge field names in your template |
| Paper Stock | 20# or 24# bond (we supply) | Do not specify paper in your file; we match to your order |
What Our Clients Say
"My mailings always go out quickly and Lori is always so nice when I drop off the letters."
Morgan Stanley
Morgan Stanley
"I wish all our vendors were as professional, accommodating and produced exceptional work product in a timely fashion like Mail Movers. Shawn and Tom are all-stars in the printing business."
Correctional Officers Association of Delaware
Correctional Officers Assoc. of DE
"You guys do a great job."
Ducks Unlimited, Inc
Ducks Unlimited, Inc
Letter Printing & Mailing FAQs
Related Services & Resources
Fundraising Appeal Letters
Specialized appeal letter printing for nonprofits with reply envelopes.
Invoices & Statements
Transactional mail printing with variable data and secure handling.
Variable Data Printing
Personalize every piece with unique names, amounts, and offers.
Lettershop Services
Full inserting, tabbing, addressing, barcoding, and USPS entry.
Targeted Mailing Lists
Reach specific demographics: age, income, homeowner status.
List Cleaning & NCOA
Clean your mailing list before printing to reduce undeliverable mail.
Informed Delivery Campaigns
Add a digital preview in subscribers' inboxes on delivery day.
MMScope Tracking
Track mail delivery, calls, and online engagement in one dashboard.