How to Calculate (and Forecast) Bad Debt Expense

Bad debt can quietly erode profits, distort forecasts, and shake financial confidence—unless you know how to stay ahead of it. To succeed, finance teams must know how to regularly calculate bad debt expense.

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Bad debt expense is a financial reality that no business can afford to ignore, yet it’s one plaguing companies of all sizes. The Kaplan Group, a commercial collections agency, found that 9% of all credit-based B2B sales turn into uncollectible losses. Over time, collecting on unpaid invoices becomes more challenging—just 10% of invoices over 12 months old are recoverable.

In other words, businesses can’t afford to have poor bad debt expense management. When customers fail to pay what they owe, it doesn’t just impact collections. It ripples through your revenue stream, distorts cash flow projections, and threatens long-term financial stability.

In periods of uncertainty or growth, knowing where you stand with bad debt can be the difference between agility and risk. For finance leaders, calculating and forecasting bad debt expense maintains compliance and reporting accuracy while equipping the business with a clearer view of financial exposure. 

It also helps drive more timely, effective debt recovery efforts. When you understand the story your receivables are telling, you’re in a stronger position to act on it before it becomes a problem.

Over time, collecting on unpaid invoices becomes more challenging—just 10% of invoices over 12 months old are recoverable.

What Is a Bad Debt Expense?

Bad debt expense is the portion of accounts receivable that a company deems uncollectible during a specific accounting period. In short, it’s the estimated amount of credit sales that will never be paid. This figure is recorded as an operating expense on the income statement and reduces both net income and accounts receivable on the balance sheet.

Companies must recognize bad debt expense to stay compliant with accounting standards like GAAP, which require matching revenues with associated expenses in the period they occur. Any errors on an organization’s financial statements could prove costly.

Bad debt expense has ripple effects across multiple areas of financial performance:

  • Profitability: Writing off uncollectible accounts reduces net income, impacting your bottom line.
  • Cash flow: It limits the amount of cash actually received, which can affect liquidity and day-to-day operations.
  • Decision-making: Inaccurate reporting of receivables can lead to poor financial forecasting and missed strategic opportunities.

When organizations consistently monitor and account for uncollectible accounts, they gain clearer visibility into financial health and can more effectively mitigate risk.

Bad debt has ripple effects across areas of financial performance, including profitability, cash flow, and decision-making.

Methods to Calculate Bad Debt Expense

There are two main ways to account for bad debt: the direct write-off method and the allowance method. The right choice depends on the size of your business, your reporting obligations, and how much precision and compliance your process demands. Let's break down each method.

Direct Write-Off Method

The direct write-off method records bad debt only after a specific account is deemed uncollectible. It’s a simple process but doesn’t match GAAP accounting standards and the accrual accounting matching principle because it doesn’t match bad debt to the period when the original sale occurred.

How to use it:

  1. Identify an unpaid invoice that is unlikely to be collected.
  2. Determine that all collection efforts have failed.
  3. Record the bad debt as an expense and reduce accounts receivable.

Example: A small business determines that a $500 invoice is uncollectible. The journal entry would be:

  • Bad Debt Expense: 500
  • Accounts Receivable: 500

This method is best suited for small businesses that don’t report under GAAP and have minimal uncollectible  amounts.

Allowance Method

The allowance method helps businesses estimate how much of their accounts receivable may eventually become uncollectible. Unlike the direct write-off method, this approach anticipates losses before they occur, using historical data or customer trends to make an informed guess.

It creates better alignment with GAAP by recording bad debt expense in the same period as the related credit sales, leading to more timely and accurate reporting.

There are two widely used approaches to the allowance method:

Percentage of Bad Debt

This approach estimates bad debts as a fixed percentage of total credit sales. It’s based on the assumption that a predictable portion of credit sales will go unpaid, using historical data as a guide.

To determine the percentage used in the calculation, businesses often analyze past performance using this formula:

Percentage of Bad Debt = Total Bad Debts / Total Credit Sales

Once this percentage is established, it’s applied to current period credit sales to calculate the expected bad debt expense:

Bad Debt Expense = Estimated % × Total Credit Sales

Example: If a company determines from historical data that 1.5% of its credit sales typically go uncollected, and current credit sales total $200,000, the calculation is:

Bad Debt Expense = 0.015 × $200,000 = $3,000

Aging of Accounts Receivable Method

The aging method evaluates the likelihood that receivables will remain unpaid by segmenting outstanding invoices into aging buckets (e.g., 30, 60, 90+ days). Each bucket is assigned a different probability of default, with older receivables carrying a higher estimated bad debt percentage.

Example: Suppose a company segments its $100,000 in receivables as follows:

  • Current: $60,000 (1% estimated uncollectible)
  • 31–60 days: $25,000 (3% estimated uncollectible)
  • 61–90 days: $10,000 (5% estimated uncollectible)
  • 90+ days: $5,000 (10% estimated uncollectible)

Bad debt expense is calculated as:

(60,000 × 0.01) + (25,000 × 0.03) + (10,000 × 0.05) + (5,000 × 0.10) = $600 + $750 + $500 + $500 = $2,350

Both approaches to the allowance method offer finance teams structured, GAAP-compliant ways to plan for losses. Choosing the right one depends on your company’s complexity, reporting needs, and how closely you want to align reserves with receivables risk.

How to Forecast Bad Debt Expense

Forecasting bad debt expense is an essential exercise in financial preparedness. Done well, it provides the insight finance teams need to strengthen reserves, manage liquidity, and avoid unpleasant surprises in the close process. Additionally, by forecasting accurately organizations can set aside an allowance for doubtful accounts in a contra asset account. Here are key actions that help create a reliable forecast:

  1. Review historical loss data: Identify trends in write-offs by customer type, product line, season, or other dimensions.
  2. Monitor payment behavior: Track aging schedules and payment delays to spot emerging risks.
  3. Assess customer creditworthiness: Re-evaluate customer segments regularly based on updated financial health or market factors.
  4. Factor in external variables: Adjust for macroeconomic indicators, industry shifts, or geopolitical events that could affect collections.
  5. Model different scenarios: Use multiple assumptions—best case, worst case, and most likely—to stress test your reserves.

Forecasting bad debt is about building operational foresight. If you know which customers are at risk of defaulting next quarter, you can act now to protect cash flow, adjust payment terms, or tighten credit.

AI-powered financial planning tools streamline how teams analyze payment trends and predict defaults, providing earlier insight and more time to respond. Then, with the right set of policies and practices in place, teams can turn forecasting insight into action.

Managing bad debt effectively safeguards revenue, business confidence in reporting, and strengthens business resilience.

Best Practices and Common Pitfalls

Managing bad debt effectively requires a blend of proactive strategy and ongoing discipline. It not only safeguards revenue but builds confidence in financial reporting and strengthens business resilience. Here’s what works and what to watch out for.

Establish Strong Credit Controls

Before extending credit, assess each customer's risk profile using a combination of credit scores, financial history, and business reputation. This helps prevent high-risk accounts from entering your receivables pipeline and reduces the likelihood of future write-offs.

Set Clear Payment Expectations

Clarity in your payment terms can prevent disputes and delays. Define invoice due dates, outline any late fees or penalties, and establish escalation steps for nonpayment—then make sure every customer understands them upfront.

Automate Invoicing and Follow-Up

Manual billing processes often lead to delays and missed reminders. Automated invoice processing ensures that invoices go out on time, reminders are triggered based on due dates, and teams can focus on resolving exceptions instead of tracking down payments.

Monitor Customer Behavior in Real Time

Spotting red flags early can prevent bad debt from growing. Regularly monitor payment delays, broken promises to pay, and shifts in order patterns as early indicators of financial stress.

Don’t Overlook the Small Stuff

It’s easy to dismiss minor unpaid balances, especially when larger issues are competing for attention. But those small amounts can add up fast—track and follow up on them consistently.

Update Your Models Regularly

Forecasting based on outdated assumptions can lead to under- or overestimating reserves. Refresh your models regularly with current customer behavior, economic shifts, and internal sales trends.

Align Your Teams Around Collections

Bad debt management isn’t just finance’s responsibility. Sales, customer service, and operations all play a role. Foster alignment across departments to ensure consistent messaging and avoid undermining payment expectations.

Final Thoughts and Next Steps

More than just a line item, bad debt expense is a key indicator of financial health and operational discipline. By understanding how to calculate it using both direct write-off and allowance methods—and by learning how to forecast future losses—finance teams can make smarter and more informed decisions about how to handle debt and limit its financial impact.

And with the support of modern financial planning platforms that unify data, streamline workflows, and enhance visibility, leaders can reduce uncertainty and improve performance across the board.

Now’s the time to take a hard look at your processes. If you’re relying on outdated systems or patchwork solutions, upgrading your tech stack could be the most impactful move you make this year.

Workday has a 97% customer satisfaction rate—but what about finance leaders specifically? Learn more about the five major factors motivating CFOs to move to Workday in our report.

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