Quick summary

• Paper check cost per payment: $4-20 (labor, materials, postage). ACH cost: $0.25-$1.50. The math favors switching at any volume.
• Vendors resist check elimination because checks are familiar. The right approach is to offer them ACH or virtual card as a convenience, not to force a cutover.
• Under 50 bills per month: Melio (free) handles vendor enrollment and ACH. 50-500 bills: BILL ($45-79/user/month) adds approval workflows and accounting sync. Over 500 bills: Tipalti or Stampli for automation at scale.
• The ACH transition typically takes 60-90 days and requires vendor enrollment (collecting banking details). Most vendor portals handle this securely with email verification.

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Most small and midsize businesses still pay vendors by paper check. Not because it’s the best method, but because it’s what they’ve always done and switching feels complicated.

The math is not kind to checks. According to NACHA (the organization that governs ACH in the US), paper check processing costs between $4 and $20 per payment when you include staff time, check stock, printer maintenance, postage, and the time spent reconciling returned or lost checks. ACH transfers cost $0.25 to $1.50 per transaction. Virtual cards are often free to the payer and generate cash back.

At 100 payments per month, that’s a difference of $375-$1,850 per month. At 500 payments per month, you’re looking at real money.

Here’s how to make the switch without losing vendors or creating reconciliation headaches.

Step 1: Understand what you’re replacing

Before switching, audit your current payment volume for one quarter:

• How many checks do you write per month?
• What’s the average payment amount?
• Which vendors receive checks vs. already accept ACH or card?
• Which payments are time-sensitive (rent, loan payments) vs. flexible?

Most businesses find that 20-30% of their vendors already accept ACH but you’ve never asked them to use it. These are the easy wins.

The remaining 70-80% will need enrollment. Some will be fast (they’ll give you their ACH details via email in 2 minutes). Some will be slow (they only take checks, at least until you explain the alternative).

Step 2: Choose a platform based on your volume

The right tool depends on how many bills you process per month.

Under 50 bills per month: Melio

Melio is free for ACH transfers. No monthly subscription, no per-user fee. You pay vendors via ACH (free) or check ($1.50 fee). The unusual feature: you can pay by credit card even if your vendor only accepts ACH. Melio charges a 2.9% card processing fee, but you earn card rewards and get 30-45 days of float before the card bill is due.

Melio is not an AP system. There are no approval workflows, no GL coding automation, and no three-way matching. For a business owner or bookkeeper paying under 50 bills themselves, this doesn’t matter. For a finance team that needs controls, it does.

50-500 bills per month: BILL (formerly Bill.com)

BILL adds the things Melio lacks: multi-step approval workflows, GL coding, QuickBooks and Xero sync, and a vendor portal for self-service banking updates. Pricing starts at $45-79/user/month depending on the plan.

BILL also offers a vendor network of 7+ million businesses who have already connected their ACH details, which reduces enrollment friction for vendors who are already on the platform.

Over 500 bills per month: Tipalti or Stampli

At higher volumes, you need AP automation features: OCR invoice capture, automatic GL coding based on past entries, exception queuing, and ERP integrations beyond QuickBooks/Xero. Tipalti starts around $2,000-3,000/month and handles global payments including international wires. Stampli is in a similar range with stronger approval workflow features.

Step 3: Enroll your vendors

Vendor enrollment is where most AP automation projects stall. Here’s what works:

Send a templated email to each vendor explaining that you’re switching to electronic payments and that it means they’ll get paid faster (typically 1-3 business days for ACH vs. 5-10 for check). Include a link to a secure vendor portal to submit their banking details.

The secure portal matters. Vendors are (correctly) suspicious of emails asking for banking information. BILL, Melio, and most enterprise AP platforms handle this with an email verification step: you send an invite, the vendor clicks a link, logs in, and enters their banking details directly into the secure portal. You never see the banking details yourself.

Don’t rush this. Set a 60-90 day transition window. Continue processing checks for vendors who haven’t enrolled yet. Follow up once after 2 weeks, once more after 4 weeks. Most will convert in that window.

Step 4: Handle the exceptions

Some vendors will not accept ACH. This is less common than you’d expect, but it happens. Options:

• Virtual card (where supported): you issue a single-use card number for each payment. The vendor charges it like a credit card. You get cash back. The downside is you may need to call the vendor to process the card payment.
• Expedited check: if the vendor absolutely requires a check, most AP platforms can mail a check on your behalf for a small fee ($1-2). This is faster than cutting a check yourself and maintains the vendor relationship.

Don’t make check elimination an all-or-nothing project. Getting from 100% check to 80% ACH/card captures most of the cost savings. The last 20% can happen gradually as vendors update their payment capabilities.

Step 5: Integrate with your accounting software

The main benefit of AP automation beyond the payment method change is the accounting integration. When a payment is processed, it should automatically sync back to QuickBooks, Xero, or whatever system you use, creating a bill payment entry linked to the correct vendor and GL account.

Without integration, you’re doing double entry: processing payment in the AP tool, then recording it manually in the accounting software. That’s the same error-prone manual work you’re trying to eliminate.

BILL, Melio (basic sync), Stampli, and Tipalti all integrate with QuickBooks and Xero. More complex ERP integrations (NetSuite, Sage Intacct) are available on higher tiers.

Frequently asked questions

Will vendors actually share their banking details with a third-party portal? Most large vendors are familiar with these portals and comfortable using them. Smaller vendors may be hesitant initially. The key is that the vendor portal is operated by the AP software company (BILL, Melio, etc.) and communicates from their domain, which is recognizable. You can also offer to collect banking details via secure form or email and enter them yourself, though that’s more work on your end.

What about vendor fraud risk? I’ve heard about ACH fraud. ACH fraud (where someone intercepts a vendor enrollment email and substitutes their own banking details) is real. The countermeasure is email verification for all banking changes: when a vendor updates their ACH details, both the old and new email addresses on file get a confirmation email, and the change is held for 24-48 hours before taking effect. Verify any banking change requests received by phone by calling the vendor at a number you already have on file, not one provided in the email.

What’s the best card to use with Melio’s credit card pay feature? The 2.9% fee needs to be offset by card rewards plus the value of the float. A 2% cash back card like the Citi Double Cash breaks even. Cards with higher earning categories (Chase Ink for business, Amex Business Gold for specific categories) can come out ahead. The float benefit (30-45 days before your card bill is due) has value even beyond the rewards if your cash flow is tight.

How long does the vendor enrollment process take? Plan for 60-90 days. Most vendors respond within 2 weeks if you follow up once. A small percentage will need multiple follow-ups or will refuse ACH entirely. You can process those remaining vendors by check indefinitely; the cost savings come from the ones who do enroll.

Do I need to notify my bank? You don’t need bank approval to start using ACH through a third-party platform. The AP software handles the ACH processing through their own banking relationships. If your volume is very high (thousands of payments per month), you may eventually want to discuss direct ACH access with your bank, but most SMBs don’t need this.