Bill Pay: What It Is & How Bookkeepers Process Vendor Payments

It's Wednesday afternoon. Your client has 14 open bills. Rent due Friday. Three vendor invoices hitting net-30 this week. One contractor who gets paid by wire because she's overseas. You pull up the AP aging, sort by due date, and run the bill pay batch.

That's what bill pay actually looks like from a bookkeeper's seat. Not a software demo. Not a feature list. A process with a tight deadline, a handful of payment methods, and a few ways it can go sideways if you're not paying attention.

What is bill pay in bookkeeping?

Bill pay is the process of paying a vendor's invoice using an agreed payment method: check, ACH, wire, or virtual card. A bookkeeper initiates the payment, records it against the open bill in the accounting system, and sends remittance advice to the vendor so they know which invoices are closed. Bill pay is the AP-side action that clears an open payable off the books. It's not the same as accounts payable, which tracks what's owed. Bill pay is the step that turns "owed" into "paid." Most small businesses run bill pay on a weekly or bi-weekly schedule, batching all due invoices into one run to simplify cash-flow planning.

Key Takeaways

• Bill pay is a process, not a product. The method (ACH, check, wire, virtual card) depends on vendor requirements, payment volume, and whether your client cares about float.
• QBO Bill Pay charges $1.50 per ACH transaction. At 60 payments per month, that's $90/month in fees many bookkeepers don't track against the client's budget.
• Bill.com sends remittance to the vendor's email of record. If that address is stale, the vendor never sees the remittance, and a duplicate-payment request follows.
• Sync-back delays are the #1 cause of AP aging mismatches at month-end. A payment sent Tuesday may not reflect in QBO until Thursday, leaving open bills that look past-due.
• Virtual cards generate rebates for the client. They're worth mentioning when your client has enough payables volume to make it meaningful (generally $50K+ per month AP).
• Growthy doesn't process payments. It categorizes the bill before payment and reconciles the cleared transaction after. That's where the GL accuracy actually lives.

Visit the Glossary for related terms, or see accounts payable for how bills enter the AP queue before bill pay runs. Each payment generates remittance advice the vendor needs, and unresolved short-pays surface in accounts payable aging at month-end.

What Bill Pay Actually Is

Bill pay is the downstream half of accounts payable. The AP side is receiving and recording vendor bills. Bill pay is paying them.

The workflow, simplified: vendor sends invoice, you enter it as a bill in the accounting system, it sits in AP aging until it's due, then bill pay clears it. Open payable becomes zero balance. Cash goes out.

What varies is how the cash goes out. That's where the method decision matters.

Bill pay tools don't change the accounting. They change the mechanics: how the money moves, how fast it settles, what remittance goes to the vendor, and how the cleared payment syncs back to your GL. Pick the wrong method for the wrong vendor and you're either paying unnecessary fees, dealing with delayed settlement, or chasing a vendor who says they never got paid.

Common Bill Pay Methods Bookkeepers Use

Check

Paper checks are slower, but some vendors still require them. Utilities, property managers, and some insurance carriers won't take ACH or virtual card. Checks are free to issue from a business checking account. The downside is mail time (3-7 business days) and manual tracking if a check gets lost.

For most clients, checks should be the exception, not the default. If your client is still mailing 30 checks a month, that's 30 opportunities for delays, stop-pay requests, and a cleared-date gap between when the check leaves and when it clears the bank.

When to use: vendors that require paper, one-off payments under $500 where ACH setup isn't worth it, payments where the physical mail date matters for a contract deadline.

ACH

ACH is the workhorse for bill pay. Bank-to-bank, 1-3 business day settlement, no physical mail. Vendors get paid predictably. Your client's bank statement matches what you scheduled.

The cost question depends on the tool. Direct bank ACH (through online banking) is typically free. QBO Bill Pay charges $1.50 per ACH transaction as of 2026. Bill.com and Melio charge $0 per ACH on their base plans but charge for same-day ACH or expedited processing.

At 20 payments per month, $1.50/ACH is $30. Manageable. At 60 payments per month, it's $90. That's over $1,000 per year for one client to use a feature inside the accounting tool they're already paying for. Worth knowing before your client scales up.

When to use: most vendor payments where the vendor accepts bank transfer, regular recurring bills, payroll-adjacent payments like benefits or contractor pay.

Virtual Card

Virtual cards are single-use card numbers generated for a specific payment amount. The vendor charges the card like any other credit card. The buyer earns rebates (typically 0.5-1.5% of spend). The payment clears the same day. Remittance is embedded in the card data.

The catch: the vendor has to accept credit cards, and some vendors pass the card-processing fee (2-3%) back to your client. A 1% rebate on a $10,000 payment is $100 back. A 2.5% card fee charged by the vendor is $250 out. Do the math before recommending virtual cards across the board.

When to use: high-volume AP clients with vendors who accept cards and don't surcharge, clients who want the float or the rebate, travel and expense-style vendor payments.

Wire Transfer

Wires settle same-day (domestic) or 1-2 days (international). They're irreversible once sent. Banks charge $15-35 per wire outgoing, and the receiving bank sometimes charges $10-15 incoming.

For bookkeepers, wires are high-risk because there's no recall. If the account number is wrong, the money is gone until the receiving bank responds to a return request. Always verify wire instructions with the vendor by phone before the first wire. Don't trust wire details in email alone.

When to use: international vendor payments where ACH isn't an option, large one-time payments over $50K where the wire fee is trivial relative to the amount, vendors who require same-day settlement.

Common Gotchas at Scale

Remittance email goes to a stale vendor address

Bill.com, Melio, and QBO Bill Pay all send remittance advice to the vendor's email of record. If that email is from three years ago when the vendor's AR clerk was someone who left, remittance disappears. The vendor doesn't close the invoice on their end. A few weeks later, they call past-due.

The what is remittance advice article covers the full duplicate-payment risk. Short version: never approve a second payment for the same vendor invoice without confirming the first remittance was received. Run a quarterly check of your Bill.com vendor list to catch stale addresses before the vendor calls you.

QBO Bill Pay ACH fees add up at volume

At low volume, $1.50 per ACH is invisible. At 50+ payments per month, it's a recurring line item that most clients haven't budgeted. Before your client scales bill pay volume inside QBO, model the annual fee against alternatives. A free bank-direct ACH batch through their online banking might cover the same use case at zero cost, with a slightly more manual workflow.

Sync-back delays create false AP aging mismatches

When you send a payment through a bill-pay tool, the payment status in your AP aging depends on how fast that tool syncs back to QBO or your GL. Bill.com syncs on a schedule, not in real time. QBO Bill Pay is tightly integrated but still has a processing delay.

The practical problem: you run bill pay Tuesday, send 12 payments. Wednesday morning, you open AP aging for a client review. Four of those 12 bills still show open because the sync hasn't completed. The aging report looks wrong. You spend 20 minutes verifying what you already know is paid.

Fix: pull AP aging after your bill-pay tool's sync window. For Bill.com, that's typically the following morning. For QBO Bill Pay, same-day but check in the afternoon. Document this in your month-end close checklist so you don't run AP aging at 8 AM the morning after a bill-pay run.

Duplicate payment from missed remittance

Your client pays Vendor A. The remittance email bounces. Vendor A calls three weeks later saying the bill is overdue. Someone on the team approves a second payment. You now have two payments for the same invoice in your books.

This is why AP aging reconciliation matters before every bill-pay run. If a vendor is calling past-due on a bill your aging shows as paid, the answer is never "pay it again immediately." The answer is "send the remittance, confirm receipt, and wait 48 hours." Most duplicate payment situations are a remittance delivery problem, not a payment problem.

How Growthy Fits Into the Bill Pay Workflow

Growthy doesn't process payments. That distinction matters because some bookkeepers think of Growthy as a bill-pay tool. It's not. It's a categorization and reconciliation layer.

Here's where it fits:

Before payment: The vendor sends an invoice. You enter it as a bill. Growthy categorizes it automatically based on the vendor, the GL account pattern from prior bills, and the transaction description. You review and approve. The bill sits in your AP queue ready for the payment run, already coded to the right expense account.

After payment: The cleared transaction hits the bank feed. Growthy matches it to the bill already in the system. The AP balance goes to zero. The bank account balance decreases. The journal entry is clean. No manual reconciliation step because the bill was already coded before the payment left.

The categorization accuracy difference between a coded bill and an uncoded payment is significant. When Growthy sees a bill entered as "Vendor A / Utilities / $842.50" before payment, the cleared transaction match is straightforward. When a bookkeeper skips the bill-entry step and posts payments directly from the bank feed, Growthy is working from a raw transaction with a bank description like "ACH DEBIT UTIL PAY 847293847" and has to categorize from context alone. The first scenario is 90%+ accurate. The second is harder.

The process discipline matters more than the tool.

FAQ

What's the difference between bill pay and accounts payable?

Accounts payable is the record of what you owe vendors. It's a liability account on the balance sheet that tracks every unpaid invoice. Bill pay is the process of clearing those invoices by sending payment. AP aging tells you what's due and when. Bill pay is the action that moves items off that aging report.

Does bill pay software integrate with QBO?

Yes, with variations. QBO Bill Pay is built directly into QuickBooks Online and syncs natively. Bill.com and Melio integrate via API and sync payments back to QBO, but on a schedule rather than in real time. The sync lag is the most common source of AP aging mismatches at month-end.

Is QBO Bill Pay worth the $1.50 ACH fee?

It depends on volume. Under 30 payments per month, $1.50 per ACH is roughly $45 monthly, which most clients absorb without noticing. Over 60 payments per month, the fee is $90 or more. At that volume, compare against bank-direct ACH (free at most business banks) or a dedicated tool like Melio, which offers free ACH on its base plan. The convenience of native QBO integration has real value; it just needs to be weighed against the fee at scale.

What remittance advice should I send with a bill payment?

At minimum: payment date, payment method, total amount, and the list of invoice numbers and amounts applied to each. That's what the vendor's AR clerk needs to close your invoices on their end. Most bill-pay tools generate this automatically. If you're paying direct from the bank or via wire, send the remittance as a PDF email the same day you send the payment.

What do I do if a vendor says they didn't receive payment but my books show paid?

Check three things before cutting a second payment: (1) confirm the cleared transaction hit the bank, (2) pull the remittance advice from your bill-pay tool and re-send it to the vendor directly, (3) confirm the vendor's AR clerk received and processed it. Most "unpaid" vendor calls are a remittance delivery failure, not a payment failure. See what is remittance advice for the full checklist on duplicate-payment risk.

Should I use virtual cards for bill pay?

Virtual cards make sense when your client's vendor accepts credit cards without a surcharge and the AP volume is high enough for rebates to be meaningful. The typical rebate range is 0.5-1.5% of spend. If vendors pass card fees back to your client (common with contractors and small service vendors), run the math first. A vendor surcharge can wipe out the rebate and then some.

The bill pay process itself is straightforward. The complications are in the details: which method fits which vendor, how fees stack at volume, whether remittance actually reached the vendor, and whether your GL reflects the cleared payment before the next AP aging review.

Get the process right and bill pay is a predictable bi-weekly task. Get it wrong and you're chasing vendor calls, reconciling duplicate payments, and explaining why the AP aging doesn't match what your client thinks they owe.

If you want cleaner categorization before payments go out and faster reconciliation after they clear, start with Growthy free. Built by a CPA firm partner who still reconciles books for real clients. Categorizes automatically. You review and approve.