What Is a 13-Week Cash-Flow Forecast for a Contractor?

A 13-week cash-flow forecast is a rolling weekly projection of expected cash receipts and cash payments over approximately the next three months.

For a construction contractor, it can help management identify:

upcoming liquidity shortages;
large project expenditures;
payroll pressure;
delayed receivables;
tax obligations;
debt payments;
owner distributions;
and potential financing needs.

The purpose is not to predict cash perfectly.

It is to give leadership enough visibility to make decisions before the bank balance becomes the problem.

Why 13 Weeks?

Thirteen weeks is long enough to capture approximately one quarter of activity while remaining short enough to forecast with useful detail.

That horizon often includes:

several payroll cycles;
multiple customer collections;
major subcontractor payments;
material purchases;
tax payments;
debt service;
and project mobilizations.

For many contractors, that makes 13 weeks a practical operating window.

Why Not Just Use a Monthly Cash Forecast?

Monthly forecasts can be useful for longer-term planning.

But they may hide short-term liquidity problems.

Suppose a contractor forecasts:

Beginning monthly cash: $1.2 million

Monthly collections: $2.5 million

Monthly payments: $2.3 million

Ending monthly cash: $1.4 million

That looks comfortable.

But the weekly detail might show:

Week 1 ending cash: $900,000

Week 2 ending cash: $350,000

Week 3 ending cash: $700,000

Week 4 ending cash: $1.4 million

The monthly forecast hides the fact that cash falls to $350,000 mid-month.

The 13-week forecast makes that visible.

Construction Cash Flow Is Timing Sensitive

Contractors often experience timing gaps between:

performing work;
paying employees;
paying suppliers;
paying subcontractors;
submitting billings;
customer approval;
and collection.

A project can be profitable while creating short-term cash pressure.

The weekly forecast shows when those timing differences collide.

What Should a 13-Week Forecast Include?

A contractor forecast will typically begin with:

Beginning Cash

Then add expected:

Cash Inflows

customer collections;
retainage collections;
approved change-order collections;
deposits;
financing proceeds;
and other significant receipts.

Then subtract expected:

Cash Outflows

payroll;
payroll taxes;
subcontractors;
materials;
equipment;
operating expenses;
debt service;
taxes;
owner distributions;
and other significant payments.

That produces:

Ending Cash

for each week.

Start With Actual Beginning Cash

The first week should begin with actual available cash.

Ideally, that balance is based on:

current bank balances;
reconciled accounting records;
and an understanding of restricted or otherwise unavailable funds.

Do not begin a forecast with an outdated general-ledger balance.

The starting point drives every week that follows.

Forecast Collections, Not Revenue

One of the biggest forecasting mistakes is using revenue as though it were cash.

Revenue tells management what has been earned.

The cash forecast needs to estimate when the customer will actually pay.

For example:

Revenue earned: $500,000

Billing submitted: $450,000

Expected collection this week: $0

The forecast should show zero cash from that customer for the week if no payment is expected.

Forecast Billings Separately From Collections

It can be useful to maintain both:

expected billing dates;
and expected collection dates.

That allows management to understand whether future cash depends on:

existing accounts receivable;
future billing;
customer approvals;
or work not yet performed.

Use Customer-Specific Collection Assumptions

Not every customer pays the same way.

One may consistently pay in:

25 days

Another may pay in:

50 days

A third may require:

owner approval;
architect certification;
lender funding;
or other steps before payment.

The forecast should reflect actual customer behavior when known.

Include Existing Accounts Receivable

The forecast should begin with current receivables and estimate when they will convert to cash.

Review:

invoice amount;
invoice date;
due date;
customer history;
current status;
disputes;
and expected payment date.

Large overdue receivables should not automatically be assumed to arrive next week.

Treat Retainage Separately

Retainage often converts to cash more slowly than normal receivables.

Forecast it based on realistic events such as:

substantial completion;
final completion;
closeout;
lien releases;
final owner approval;
or other contractual requirements.

A large retainage balance may be economically valuable but unavailable for current payroll.

Be Careful With Pending Change Orders

A pending change order may ultimately generate cash.

That does not mean it belongs in the base forecast at full value.

Management should consider:

approval status;
probability of approval;
amount expected to be approved;
expected billing date;
and expected collection date.

Uncertain inflows may be better reflected in a separate scenario.

Forecast Payroll by Exact Week

Payroll is often one of the largest recurring cash outflows.

Include actual expected dates for:

regular payroll;
overtime;
bonuses;
payroll taxes;
benefits;
union obligations;
and owner payroll where applicable.

Weekly forecasting is particularly useful because payroll may not align cleanly with monthly accounting periods.

Watch for Three-Payroll Months

For contractors using biweekly payroll, certain months will have three payroll dates.

A monthly forecast using average payroll may miss that cash spike.

A 13-week schedule should capture the actual pay dates.

Forecast Subcontractor Payments

For each major project, estimate expected subcontractor cash outflows based on:

approved pay applications;
payment terms;
retainage;
upcoming work;
known commitments;
and project schedules.

Large subcontractor payments can create substantial week-to-week swings.

Include Material Purchases

Material purchases should be scheduled based on expected payment timing.

That may include:

deposits;
progress payments;
delivery payments;
COD purchases;
and normal vendor invoices.

Long-lead items are especially important.

A large deposit in week four can materially change the liquidity picture.

Include Committed Costs

Do not limit the forecast to invoices already in accounts payable.

Known future obligations may include:

purchase orders;
subcontract commitments;
equipment orders;
material deposits;
and other contractually committed costs.

The forecast should look forward.

Include Equipment Purchases

Equipment can create large cash movements.

Track:

purchase price;
down payment;
financing proceeds;
loan funding;
trade-in proceeds;
and payment date.

A contractor may be profitable and still create a liquidity problem through poorly timed capital expenditures.

Include Debt Payments

Forecast the full cash payment for:

equipment loans;
term debt;
leases;
lines of credit;
and other financing.

The income statement may only show interest expense.

The cash forecast needs the full principal-and-interest payment.

Include Taxes

Include expected:

payroll tax payments;
federal estimated taxes;
state taxes;
sales or excise taxes where applicable;
property taxes;
and owner tax distributions.

Tax payments can create significant cash spikes if they are not planned.

Include Owner Distributions

Owner distributions should be visible as their own line item.

That makes it easier to evaluate whether a planned distribution is affordable given:

upcoming payroll;
project costs;
taxes;
debt;
bonding needs;
and future liquidity.

Today's bank balance may already be committed to tomorrow's work.

Include Company Overhead

Weekly or recurring operating costs may include:

office payroll;
rent;
insurance;
software;
utilities;
professional fees;
vehicle costs;
marketing;
and other administrative expenses.

Smaller items can often be grouped.

Large or unusual costs should be shown separately.

Track the Lowest Cash Point

One of the most useful outputs from a 13-week forecast is the projected minimum cash balance.

For example:

Week 1: $1.2 million

Week 5: $800,000

Week 8: $275,000

Week 13: $1.5 million

The business may look healthy at the beginning and end.

Week eight is where liquidity risk exists.

Establish a Minimum Liquidity Threshold

Some contractors establish a minimum cash or liquidity threshold.

For example:

Minimum operating cash: $500,000

If the forecast shows cash dropping to $275,000, management has time to consider alternatives before the shortage occurs.

The appropriate threshold depends on factors such as:

payroll;
fixed overhead;
project commitments;
customer concentration;
debt service;
and business risk.

Show Line-of-Credit Availability

A useful forecast may also track:

line-of-credit limit;
outstanding balance;
available borrowing;
planned draws;
and planned repayments.

That helps management distinguish between:

cash on hand

and

total available liquidity.

Do Not Treat the Line of Credit as Revenue

Borrowing can solve a timing problem.

It does not create project profitability.

If the forecast consistently requires increasing line-of-credit draws, management should investigate why.

Potential causes may include:

slow collections;
underbilling;
margin fade;
rapid growth;
excessive distributions;
or operating losses.

Tie the Forecast to WIP

WIP provides important inputs into a cash forecast.

It can help management identify:

underbillings;
overbillings;
remaining project costs;
expected project margin;
and backlog.

For example:

A project that is heavily overbilled may currently support cash but still have substantial future costs.

A significantly underbilled project may continue consuming cash until billing catches up.

Tie the Forecast to Job Costing

Reliable job-cost information helps estimate future cash outflows.

That includes:

remaining labor;
committed materials;
subcontract balances;
equipment;
and other project costs.

If job costing is inaccurate, the cash forecast can underestimate future spending.

Project-Level Forecasting Improves Accuracy

For major jobs, contractors can forecast cash separately.

For each project:

Inflows

current receivable collections;
expected progress billings;
retainage;
change orders.

Outflows

payroll;
materials;
subcontractors;
equipment;
project overhead.

Those project schedules can then feed the company-wide 13-week forecast.

Forecast by Payment Date, Not Accounting Date

The 13-week forecast should focus on cash movement.

For example:

An expense is recorded on September 30.

The vendor will be paid October 15.

For the cash forecast, October 15 is what matters.

Cash forecasting and accrual accounting serve different purposes.

Use a Base Case

The base case should reflect management's most reasonable current expectation.

Avoid building the forecast around ideal assumptions.

If a customer historically pays in 50 days, do not assume 30 days merely because that is what the contract says.

The forecast should be useful, not optimistic.

Add a Downside Scenario

A downside scenario can help answer:

What happens if something goes wrong?

For example:

largest customer pays 30 days late;
major project costs increase;
new job starts early;
retainage release is delayed;
or equipment purchase cannot be postponed.

This shows how much cushion exists.

Add a Growth Scenario

Growth may require additional:

labor;
project managers;
materials;
equipment;
subcontractors;
insurance;
and working capital.

A growth scenario can quantify the cash required to support new work.

Update the Forecast Every Week

A 13-week forecast should be rolling.

At the end of each week:

Replace forecasted activity with actual results.
Compare actual versus forecast.
Investigate significant variances.
Update assumptions.
Add a new week at the end.

The forecast always looks approximately 13 weeks forward.

Compare Forecast to Actual

Forecast accuracy improves through repetition.

Suppose:

Forecast collection: $700,000

Actual collection: $300,000

Management should determine why.

Maybe:

the customer paid late;
the invoice was submitted late;
approval was delayed;
or the assumption was unrealistic.

That information improves future forecasts.

Assign Owners to Major Assumptions

The accounting team may maintain the forecast.

But many assumptions belong to other people.

For example:

Project Manager

billing timing;
subcontractor payments;
material needs;
change orders.

Accounting

receivables;
payables;
payroll;
actual cash.

Leadership

equipment;
hiring;
distributions;
financing.

The forecast becomes stronger when operational owners contribute to it.

Hold a Weekly Cash Review

A brief recurring meeting can review:

current cash;
current receivables;
expected collections;
large upcoming payments;
projected low point;
line-of-credit availability;
material forecast changes;
and actions required.

The forecast should drive decisions.

It should not simply become another spreadsheet nobody reviews.

Use the Forecast to Improve Collections

If a future cash shortage depends on one large receivable, management can act now.

That may mean:

contacting the customer;
resolving documentation;
correcting billing issues;
escalating a dispute;
or confirming expected payment timing.

Cash forecasting converts collections from a historical report into a forward-looking management process.

Use the Forecast to Time Equipment Decisions

Suppose management is considering a:

$400,000 equipment purchase.

The forecast shows cash reaches its low point in four weeks.

Management can evaluate whether to:

delay the purchase;
finance more of it;
adjust the down payment;
or proceed as planned.

The forecast gives the decision financial context.

Use the Forecast to Plan With the Bank

A forecast can make banking conversations more proactive.

Instead of:

“We need money immediately.”

Management can say:

“Our forecast shows a temporary $600,000 liquidity gap beginning in six weeks, primarily because two projects mobilize before collections begin.”

That is a fundamentally different conversation.

Use the Forecast to Plan Growth

Before accepting a large project, incorporate it into the 13-week model.

Estimate:

mobilization;
payroll;
materials;
subcontractors;
billing;
collections;
and retainage.

This helps determine whether the company can finance the new work.

Use the Forecast to Evaluate Distributions

A contractor may have $2 million in cash today.

The 13-week forecast may show that $1.5 million is required over the next eight weeks.

That context should inform owner-distribution decisions.

Current cash and excess cash are not necessarily the same thing.

Common 13-Week Forecasting Mistakes

Common mistakes include:

forecasting revenue instead of collections;
using billing dates as collection dates;
ignoring retainage;
assuming pending change orders will be approved;
excluding committed costs;
using monthly averages for payroll;
forgetting debt principal;
omitting taxes;
ignoring distributions;
failing to model new-project starts;
using unrealistic payment assumptions;
and failing to update the forecast weekly.

A forecast is only as strong as its inputs.

Keep the Model Simple Enough to Maintain

A useful forecast does not need thousands of lines.

Focus on the cash movements that materially affect decisions.

Those usually include:

large customer collections;
payroll;
major subcontractors;
material purchases;
debt;
taxes;
equipment;
distributions;
and unusual expenses.

Overly complicated forecasts often stop being updated.

What Should Management Review Each Week?

At minimum, consider:

current cash;
next 13 weeks of ending cash;
lowest projected cash point;
expected customer collections;
overdue receivables;
major vendor and subcontractor payments;
payroll;
debt;
taxes;
major equipment;
line-of-credit availability;
and significant forecast changes.

The goal is to identify what requires action.

The Bottom Line

A 13-week cash-flow forecast gives contractors short-term visibility into expected:

cash receipts

and

cash payments.

It can help identify:

liquidity shortages

large project expenditures

payroll pressure

delayed receivables

working-capital needs

and

potential financing requirements

before they become urgent.

The forecast does not need to predict every dollar.

It needs to show management where cash is headed early enough to do something about it.

How Bilotta & Company Can Help

Bilotta & Company, CPAs, LLC works with construction contractors on cash-flow forecasting, WIP reporting, job costing, working-capital planning, accounting, tax, financial statement assurance, and financial leadership.

Through our Contractor Compass® Financial Stewardship program, we help contractors build rolling forecasts that connect:

project activity

billing

collections

payroll

subcontractors

working capital

financing

and

growth decisions.

Our Financial Stewardship as a Service® rhythm is:

Close → Analyze → Forecast → Decide.

A 13-week forecast puts that rhythm into practice.

It gives leadership a clearer view of what is coming while there is still time to act.

Explore Contractor Compass® →

Visit the Construction Contractor Financial Resource Center →

This article is provided for general educational purposes and should not be considered accounting, tax, legal, bonding, lending, or financial advice for a specific contractor. Forecast assumptions, liquidity requirements, and financing needs vary based on project mix, contract terms, business structure, and other circumstances.