Choosing the right direct mail format is about more than budget. It’s about making sure your campaigns have the right impact. Self-mailers, tri-folds, and bi-folds each offer unique advantages that can affect both your costs and your results.
This guide breaks down how these formats compare across printing, folding, and postage costs. You’ll see which option delivers the best value depending on your campaign size, goals, and message.
Cost comparison of self-mailers, tri-folds, and bi-folds
Self-mailers, tri-folds, and bi-folds are all folded printed pieces that can be mailed without an envelope. Each format has different cost implications that affect your overall campaign budget.
- Self-mailers: Printed sheets folded into panels and sealed for mailing without an envelope. They eliminate envelope costs while providing plenty of space for your message.
- Tri-folds: A single sheet divided into three panels, folded in a letter-style format. They offer more content space than bi-folds but come with slightly higher production costs.
- Bi-folds: A single sheet folded in half, similar to a greeting card. These typically use the least paper and are often the most cost-effective option.
In most cases, bi-folds are the cheapest, followed by tri-folds. Both formats usually cost less than traditional letter packages, which require separate inserts and envelopes.
Print and paper costs at different volumes
- Small runs (500–1,000 pieces):
- Bi-folds are most economical
- Tri-folds cost slightly more due to extra folding
- Self-mailers may require heavier paper stock, increasing costs
- Medium runs (5,000–10,000 pieces):
- All formats become more cost-efficient
- Paper weight differences become more noticeable
- Bi-folds maintain their cost advantage
- Large runs (50,000+ pieces):
- Volume discounts significantly lower per-piece costs
- Production efficiencies make all formats more affordable
- Paper choice becomes the main cost driver
Folding and assembly labor
How your piece is folded affects both time and cost. In-line folding during printing is the most efficient.
- Bi-folds: Require just one fold, making them the simplest and cheapest to produce.
- Tri-folds: Require two folds, slightly increasing production complexity.
- Self-mailers: Often require wafer tabs or glue lines to meet USPS rules, adding small costs.
Postal rate impact by format
Postage is often the largest expense in a direct mail campaign. To qualify for the lowest USPS letter rates, your mailpiece must:
- Measure between 3.5" × 5" and 6.125" × 11.5"
- Be no thicker than 0.25 inches
- Weigh no more than 3.5 ounces
Self-mailers, tri-folds, and bi-folds can all qualify when designed properly. If your piece exceeds these limits, you’ll pay higher rates for “flats” or “parcels.”
USPS size and sealing rules that keep postage low
Following USPS guidelines is crucial for keeping postage costs down.
- Bi-folds: Typically need two 1-inch tabs on the top edge when the fold is at the bottom
- Tri-folds: Usually require three tabs—two on the top edge and one on the trailing edge
- Self-mailers: Can use glue lines or wafer seals depending on the fold
Common mistakes that trigger surcharges include: incorrect fold orientation, missing or misplaced tabs, using perforated tabs, improper address placement, or exceeding size/weight limits.
At Lob, we automatically check mail designs against USPS requirements before production, helping you avoid these costly errors.
Pros and cons of each format for marketing ROI
| Format |
Pros |
Cons |
| Self-mailer |
Versatile layouts, strong visual appeal, no envelope costs |
Needs heavier stock, requires sealing, slightly higher production costs |
| Bi-fold |
Lowest cost, simple to produce, large uninterrupted panels, easy USPS compliance |
Limited content space, fewer panels for messaging |
| Tri-fold |
Organized into three sections, more space than bi-fold, familiar and easy to navigate |
Requires more folds and tabs, smaller panel size |
How to choose the right format for your campaign
- Audience privacy needs:
- For sensitive content, use formats that conceal content when folded.
- For promotional content, open layouts work well.
- Message length and creative real estate:
- Bi-folds: Best for short, impactful messages with large graphics or photos.
- Tri-folds: Ideal for step-by-step instructions, product features, or logical sections.
- Self-mailers: Great for detailed product comparisons, multiple offers or coupons, or storytelling.
- Budget and speed to market:
- Bi-folds: Fastest and least expensive.
- Tri-folds: Slightly more cost and production time.
- Self-mailers: More design effort but can deliver higher impact.
Design tips that cut costs without cutting response
Smart design choices help maximize impact without overspending:
- Use standard dimensions (8.5" × 11" or 11" × 17" folded to letter size)
- Design with folding in mind; avoid placing critical content on fold lines
- Skip complex die-cuts—simpler formats are cheaper and faster
- Choose standard paper stocks over specialty weights
At Lob, our Print Delivery Network optimizes production for both speed and cost efficiency.
Use variable data only where it matters
Personalization improves response rates, but too much variability can raise costs. Focus on high-impact areas like recipient names, offers, or local data.
Our platform makes it easy to add personalization where it matters most without unnecessary complexity.
Keep CTAs above the fold
Strong call-to-action placement boosts results without raising costs:
- Position CTAs prominently
- Use contrast to make them stand out
- Keep language clear and direct
- Offer multiple response options (QR codes, URLs, phone numbers, reply cards)
Testing mail formats with automated workflows
Testing different formats ensures you find the most cost-effective choice for your audience.
- Split test: Divide your audience into equal groups—bi-fold, tri-fold, self-mailer.
- Track delivery and conversions: Measure delivery, response, conversion, and time to response.
- Compare CPA: Calculate cost per acquisition (CPA) for each format and use the winner in future campaigns.
Bring direct mail costs down with Lob
Lob’s platform automates the entire direct mail process, helping you create cost-effective campaigns at scale.
- Our Print Delivery Network routes jobs to the nearest production facility, reducing postage and delivery time
- We support all standard formats with automated USPS compliance checks
- By connecting Lob to your CRM or marketing automation platform, you can trigger personalized mail automatically
See how Lob can help you reduce the overall cost of your direct mail campaigns: lob.com/sales.
