Quick answer: Firms struggle with invoice payments mainly because of unpredictable hourly billing, unenforced engagement letter terms, inconsistent billing structures across clients, manual payment methods, write-offs that quietly erode realization, partners spending billable hours on collections, and payments that never sync cleanly with the books. 

Accounting and professional services firms are, on paper, the people best equipped to manage money. So, it’s a little ironic how often they struggle to collect their own. The reasons usually aren’t about difficult clients. They’re about habits baked into how firms bill, most of which are easy to spot once you know where to look. 

Why do accounting firms get paid late? 

One widely cited industry survey found 81% of accounting firms get paid late, with 43% paid 15 or more days past terms. That’s not a client problem so much as a billing structure problem, and it shows up in a handful of predictable ways. 

Hourly billing creates sticker shock at the worst possible moment 

Open an invoice, see a number of hours you weren’t expecting, and the instinct isn’t to pay. It’s to wonder if something was overbilled, then set it aside and deal with it later. That hesitation is built into hourly billing itself; clients can’t budget for a number they don’t know in advance. Firms that move toward fixed fees or retainers, or that at least spell out scope clearly in the engagement letter, run into this far less often. 

Engagement letter terms get agreed to and then forgotten 

Every engagement starts with a signed letter laying out payment terms, retainer amounts, billing cadence, all of it. Then the actual invoicing happens weeks or months later, often handled by whoever’s free that day, not whoever negotiated the terms. Nothing connects the invoice back to what was originally agreed, so the terms exist on paper and nowhere else. 

Billing structures vary too much to be predictable 

A retainer client here, an hourly client there, a third on a fixed fee tied to project milestones. Professional services firms end up with one of the widest swings in days’ sales outstanding of any industry because of this mix, and firms that rely on manual follow-up commonly land around 60 days against typical net 30 terms. Standardize what you can, automate the reminders for what you can’t. 

Clients still have to mail a check or call the office to pay 

Some clients will dutifully write a check, find a stamp, and get it in the mail. A lot more will let it sit on a desk for two weeks because it’s one more errand on a long list. A payment portal that takes ACH, card, or instant transfer removes most of that friction; people pay faster when paying is the easiest thing on their to-do list, not the most annoying. 

Write-offs and discounts quietly erode what actually gets collected 

This one isn’t really about late payments at all. It’s about firms never billing the full value of the work in the first place. Realization rate benchmarks for accounting firms sit roughly between 86% for larger firms and 92.5% for smaller ones, meaning even well-run firms lose somewhere between 8 and 15% of billed work to write-downs and discounts. That gap shows up in cash flow long before anyone thinks to call it a collections issue. 

Partners and staff spend billable hours chasing their own invoices 

There’s something a little absurd about a firm built around managing other people’s finances losing hours every week to its own overdue invoices. Every hour spent following up on a late payment is an hour not spent on client work, and that math never works in the firm’s favour. Automated reminder sequences take this off someone’s plate entirely, so collections don’t depend on a partner remembering between client calls. 

Payments and the books don’t talk to each other 

A client finally pays, and now someone has to match that payment to the right invoice, the right client account, and the right line in the accounting system by hand. Do that across a few hundred clients, and reconciliation turns into its own part-time job. This is what the Forwardly Business Network handles automatically, matching payments to the right invoice and client record and syncing directly with QuickBooks Online or Xero, so nobody’s playing matchmaker between a bank deposit and a spreadsheet. 

Frequently asked questions 

Why do clients pay accounting firms late?
Mostly because of unpredictable hourly invoices, payment terms that exist in an engagement letter but nowhere in the actual billing process, and payment methods like checks that add unnecessary friction, not because clients can’t or won’t pay. 

How can accounting firms get paid faster?
By offering a client payment portal with multiple payment options, locking down payment terms at the engagement letter stage, setting up recurring invoicing, automating payments and reminders, and syncing payments directly with accounting software so nothing needs manual reconciliation. 

What is a realization rate in accounting?
The percentage of billed work a firm actually collects after write-downs and discounts. Industry benchmarks run from about 86% at larger firms to 92.5% at smaller firms. 

What’s a normal DSO for professional services firms?
It varies more than most industries because of mixed billing structures, but firms relying on manual collections commonly land around 60 days, well past standard net 30 terms. 

Let Forwardly handle collections so your team can get back to client work 

Most of what’s listed above isn’t a willpower problem. It’s a tooling problem, and it’s the kind that gets fixed once instead of managed forever. 

For retainer clients, Forwardly sets up recurring invoicing so the bill goes out on schedule every month without anyone building it from scratch. For everything else, automated payments mean clients can pay through ACH payments, card, or instant transfer the moment they get the invoice, instead of waiting until they’re near a stamp and an envelope. Automated reminders handle the follow-up that used to fall on a partner’s plate between client calls: a heads-up before the due date, a nudge on it, and a firmer follow-up if it slips past. 

Once a payment comes in, it doesn’t sit in limbo waiting for someone to match it to the right invoice. The Forwardly Business Network reconciles it automatically against the correct client record, and everything syncs directly with QuickBooks Online or Xero, so your books are accurate without anyone touching a spreadsheet. 

None of this requires your firm to change how it bills clients. It just removes the manual work sitting between sending an invoice and actually having the cash in the bank. If that sounds useful, get in touch with Forwardly, and we’ll walk you through what it looks like for your firm specifically.