What Is Projecting Accounts Receivable?

Projecting receivables means estimating how much of what you are owed will actually arrive, and in which week. It is the single largest input to any cash forecast, and it is where most forecasts go wrong.

Do not use stated terms

The most common error is timing every invoice by its due date. Terms describe what you asked for. Your aging report describes what you get, and for most businesses there is a persistent gap between the two.

If a customer has paid consistently later than terms across several invoices, they will do so again. Forecasting otherwise produces a cash projection that is optimistic in a predictable direction, which is worse than one that is simply uncertain.

Build it from payment history

• Group customers by observed payment behaviour rather than by agreed terms
• Calculate the average days to payment for each group, from actual data
• Apply that to open invoices to estimate collection dates
• Adjust for anything you specifically know: a disputed invoice, a customer in difficulty, a promised date

Use collection probability by age

Older receivables are less likely to be collected, and the deterioration is usually steeper than people expect. Applying a probability to each aging bucket, based on your own history, produces a more honest projection than treating all open invoices as certain.

If you have not tracked this before, start now. A few months of data on what actually cleared from each bucket is more useful than any general rule.

Concentration is a risk, not a detail

If one customer accounts for a large share of open receivables, your projection depends heavily on one behaviour. That warrants modelling separately rather than blending it into an average, and it warrants a downside case where they pay late.

Feeding the cash forecast

The output is a week-by-week schedule of expected receipts, which becomes the cash-in section of your rolling forecast. Each week, compare projected against actual collections and note the variance. That comparison is what makes the next projection better.

What it requires

Current, reconciled books and an accurate aging report. A projection built on an aging that includes credit balances, non-trade items, or invoices already paid but not applied will be wrong regardless of method.

Start with an accounts receivable rollforward

Opening receivables plus new credit sales, less collections, credits, write-offs, and other approved adjustments equals ending receivables. Build the forecast at enough detail to preserve those movements. Reconcile the opening balance to the closed ledger and customer aging before projecting anything.

Forecast collections from open invoices

For material invoices, use due dates, disputes, promised-payment dates, retainage, payment plans, and known customer events. Apply collection patterns to the remaining population by aging bucket, customer type, terms, or invoice cohort. Do not assume every overdue balance follows the same curve.

Add future billings separately

Translate the sales or delivery forecast into expected invoice dates, contractual terms, and collection dates. Separate work completed from invoices issued when billing depends on milestones, approvals, time entry, or customer acceptance. This prevents revenue timing from becoming an unsupported cash assumption.

Model uncertainty transparently

Use a base case plus focused downside and upside cases. Vary the assumptions that matter, such as billing delay, dispute resolution, customer concentration, collection rate, or a large promised payment. Label management actions and triggers rather than hiding optimism in one blended percentage.

Reconcile forecast to actual

After each close, compare expected collections, billings, credits, write-offs, and ending receivables with actual results. Classify differences as timing, volume, customer behavior, operational execution, data correction, or assumption error. Update future curves only when evidence supports the change.

Projection control checklist

• Opening aging agrees to the general ledger
• Credit-sales inputs agree to the operating forecast
• Existing invoices and future billings are separate
• Credits, disputes, and write-offs remain visible
• Collection assumptions have sources and owners
• Scenarios identify triggers and actions
• Forecast-to-actual variance is retained

Document the forecast population and cutoff. Exclude non-trade receivables, intercompany amounts, deposits, tax balances, or financing items unless the model explicitly addresses them. For multiple entities or currencies, preserve the source-currency schedules, rates, translation date, and consolidation logic. Review whether concentration makes a portfolio average misleading. A single large customer may deserve its own collection path, evidence, and downside case. Tie the final ending balance back to the projected balance sheet and use the collection schedule, not a separate unsupported percentage, in the cash forecast.

Assign one owner to approve assumptions and another reviewer to trace the model to the aging, sales plan, and cash forecast. Record the forecast date, covered entities, currency, version, preparation time, and material limitations. Preserve prior versions so apparent improvement cannot be created by overwriting the original expectation.