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Free Construction Cash Flow Boost Calculator with 13-Week Forecast & Business plus Project Variables

Build a 13-week Cash Flow Forecast for your construction business, then test practical ways to improve your Cash Flow.

Forecast across your whole business or build your forecast from data on your individual Construction Projects being delivered, including expected Progress Claim payments, approved Variations, Retention Moneys, Project costs, Payroll, Overheads and other business payments.

Free to use and no sign-up required to build your forecast.

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About this Article

  • Last Updated: 27 August 2026
  • Date Published: 13 August 2023

Table of Contents

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Use our free Construction Cash Flow Calculator and our Construction Cash Flow Boost Calculator to build a 13-week Cash Flow Forecast for your construction business.

Forecast the cash flow of your business as a whole or build the forecast from individual Projects so you can see how Project cash movements affect the business overall.

The calculator includes Progress Claims, approved Variations, Retention Moneys, Project costs, Overheads and other business payments. It’s designed for construction, civil and infrastructure businesses and the unique costs, expenses and cash flow issues they struggle with, rather than general small business Cash Flow.

Who is the Construction Cash Flow Calculator for?

This free Construction Cash Flow Calculator is for construction business owners and decision-makers who want to see when cash may run short, which Projects are using cash and how much money is sitting in Progress Claims, approved Variations and Retention Moneys. You can use it for a whole-of-business forecast or build the forecast from individual Projects.

The Construction Cash Flow Calculator builds a 13-week Cash Flow Forecast for your construction business. Enter whole-of-business figures, or build the forecast Project by Project, and the calculator shows your lowest forecast cash position, the week it happens, your remaining finance headroom and the Retention Moneys already due to you.

Enter cash in the week you reasonably expect it to reach or leave your bank account. If you submit a Progress Claim in Week 1 and expect payment in Week 4, put the cash in Week 4. Do not enter client names, Principal names, Project addresses or contract numbers anywhere in this tool.

13-week Cash Flow Forecast
Build your 13-week Cash Flow Forecast
Your forecast start date
Use today, the next Monday, or another date that matches how you normally prepare your weekly forecast. The calculator creates 13 consecutive seven-day periods from this date.
Your starting position
The cleared cash in your business bank accounts at the start of Week 1. Do not include undrawn finance facilities.
The total approved limit of any overdraft or working capital facility you want included in the forecast.
The amount of that facility already used at the start of Week 1. The calculator shows the remaining undrawn headroom separately.
Expected business cash movements over the next 13 weeks

Enter amounts only in the week you reasonably expect the cash to be received or paid. Do not enter amounts already included in your opening cash balance. Weeks 1 to 7 are shown here. Use the button underneath the table to enter Weeks 8 to 13.

Business cash movements, Weeks 8 to 13
Build the forecast from your Projects

Add the Projects you want to forecast individually. For privacy, use labels such as Project 1, Project 2 or Project A. Do not enter client, Principal, site or other identifying names.

Other business cash movements

Enter only whole-of-business receipts and payments that are not already included in the Project figures above. Weeks 1 to 7 are shown here. Use the button underneath the table to enter Weeks 8 to 13.

Other business cash movements, Weeks 8 to 13
Lowest forecast cash position$0
When it occurs-
Approved finance still available$0
Your approved facility limit less the amount already drawn. This is finance you may still be able to draw, not cash already in your bank account.
Retention due or overdue$0
Your 13-week Business Cash Flow Forecast
Important. This calculator is a general planning tool only. It uses the figures and assumptions you enter and shows possible Cash Flow outcomes over the selected 13-week period. It does not verify whether amounts will be received or paid when expected, whether Variations or Retention Moneys are recoverable, or whether any tested improvement can be achieved. The results are not accounting, financial, legal, tax, lending or investment advice and should not be relied on to make business or funding decisions. If your forecast shows a cash shortfall, or you want help working through the assumptions and the reasons cash is tight in your construction business, speak with Shannon Drew at Blaze Business & Legal before acting on the results.
Cash Flow Boost Calculator
Test your Cash Flow scenarios

Your 13-week forecast is linked automatically and you do not need to enter it again. Test collecting Progress Claims sooner, recovering Retention Moneys already due, bringing approved Variation payments forward, reducing controllable Overheads, or negotiating different future Supplier payment terms, and compare the possible effect on cash available over the same 13 weeks.

Unlock the Cash Flow Boost Calculator

Enter your details to test the forecast you have already built. Do not enter client names, Principal names, Project addresses, contract numbers or other identifying Project information anywhere in this tool.

Get Progress Claims paid faster
The total value of Progress Claims already made, or expected to be made, that you currently expect to receive during this 13-week period. Do not enter amounts already received before Week 1.
Recover Retention Moneys that are already due
Only model Retention Moneys that have already become due for release under the relevant Contract. Do not assume Retention can be recovered early.
Collect approved Variations earlier
Enter only Variations that are approved and that you reasonably expect to be paid during this 13-week period.
Reduce controllable Overheads
Include only Overheads you could realistically reduce, cancel, renegotiate or defer within the next 13 weeks. Examples include unused software or subscriptions, discretionary travel, some professional or consulting costs, non-essential office spending and advertising. Do not include rent or lease payments unless you genuinely have an option to change them during the period. Do not include Payroll, committed Project costs, tax, Superannuation or amounts you are already contractually required to pay.
Change agreed Supplier payment timing
Include only future Supplier payments where different payment terms could genuinely be negotiated. Do not use this control to model paying existing obligations late.
Possible improvement to your business Cash Flow over the next 13 weeks
$0

Based on the changes you have tested, this is the possible improvement to cash available in your business over the same 13-week period.

Steps to work towards this improvement
  1. Adjust one or more controls above to create your scenario.
Important. The Cash Flow Boost Calculator shows possibilities only. Moving a slider does not mean the change can be achieved, that cash will be received earlier, or that an expense can safely be reduced or delayed. Results depend entirely on the figures and assumptions you enter. Do not rely on these results as accounting, financial, legal, tax, lending or investment advice. Before acting on a projected improvement, speak with Shannon Drew about what is commercially realistic for your business.

Share my results creates a link to this calculator carrying the financial scenario you entered. It does not create a new webpage. Anyone with the link can see the figures in the shared scenario, so do not enter client names, Principal names, Project addresses, contract numbers or other identifying Project information.

Download your Construction Cash Flow Report

Your report includes your 13-week Business Cash Flow Forecast, the key forecast results, a Project summary where Projects were used, Retention Moneys due or overdue, your Cash Flow Boost scenarios, the steps generated from the options you tested, the assumptions and the calculator disclaimer.

For example Managing Director, CFO, Commercial Manager or Finance Manager.
Would you like Shannon to help you work through the result?

The calculator can show a possible Cash Flow gap or improvement. It cannot tell you whether the assumptions are realistic for your business. Shannon Drew can review your forecast with you and talk through the financial issues behind the result.

The report uses the forecast and scenario figures already entered into this calculator. You do not need to re-enter them.

Talk to Shannon
A forecast tells you what is coming, not what to do about it

Shannon Drew is a Management Accountant, Fractional CFO and Business Adviser with 25+ years in the construction industry. He reviews your forecast with you, tests whether the assumptions hold, and works out what is driving the shortfall before you make a funding decision on it.

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Construction Cash Flow Report

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Prepared from the Blaze Business & Legal Construction Cash Flow Calculator. Forecast starting '+esc(val('forecastStart'))+', 13-week period.

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Lowest forecast cash position'+money(f.low)+'
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Retention due or overdue'+money(f.rd)+'
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13-week Business Cash Flow Forecast

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Project Retention summary

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Cash Flow Boost scenario

Possible improvement to cash available in your business over the next 13 weeks
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Steps generated from the options you tested

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Assumptions to review

This report is based entirely on the cash amounts, timing and scenario assumptions entered into the calculator. Review Progress Claim payment timing, approved Variation receipts, Retention release dates, Project costs, Overheads, tax and finance payments before relying on the forecast for internal planning.

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Important disclaimer. This report and the calculator are general planning tools only. They do not verify whether amounts will be received or paid when expected, whether Variations or Retention Moneys are recoverable, or whether any Cash Flow improvement can be achieved. They are not accounting, financial, legal, tax, lending or investment advice and should not be relied on to make business or funding decisions. Speak with Shannon Drew at Blaze Business & Legal about the assumptions and what is commercially realistic for your construction business before acting on the results.
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Why Is Construction Cash Flow Different From a General Business Cash Flow Forecast?

Construction businesses often spend substantial amounts on Labour, Subcontractors, Materials and Plant before the corresponding Project revenue reaches the bank account.

Progress Claims may take weeks to be assessed and paid. Retention Moneys can remain withheld for months or years. Variation work may already have been completed and paid for while the Variation itself remains unpaid.

A general Cash Flow Calculator that asks for monthly sales and expenses does not show these timing differences particularly well.

Should Construction Cash Flow Be Forecast by Project or Across the Whole Business?

Both views can be useful.

The whole-of-business forecast shows whether there is enough cash available to meet the commitments of the business over the coming 13 weeks. It includes the combined effect of Projects, Overheads, tax payments, finance commitments and other cash movements.

The Project view shows what is happening underneath that total. One Project may be generating cash while another is absorbing it. If only the company bank balance is being watched, that distinction can be difficult to see.

A business with several active Projects can therefore look reasonably healthy overall while one Project continues to require funding from the others.

Progress Claims Need to Be Forecast When the Cash Is Expected

The value of work completed is not necessarily the amount of cash available to the business.

A Progress Claim may be prepared at the end of one month, submitted several days later, assessed by the Principal or Superintendent and then paid under the Contract’s payment terms. The cash might not reach the bank account until well into the following month.

That timing matters when Payroll, Subcontractors and Suppliers are due before the Progress Claim is received.

A useful Construction Cash Flow Forecast therefore looks at when Project money is realistically expected to arrive, not simply when revenue is earned or a claim is submitted.

Retention Moneys Should Be Actively Tracked Until They Are Released

Retention Moneys often runs across a portfolio of Projects. Part of each Progress Claim may have been withheld even though the business has already paid the costs of carrying out the work. The result is cash earned on completed work sitting outside the business.

The problem becomes more obvious after Practical Completion. The Project team moves on, commercial attention shifts to new Projects and an old Retention can remain outstanding much longer than it should.

Construction businesses should keep a current record of the Retention Moneys held on every Project, the amount due for release, the relevant contractual release date and whether payment has been received. Where Retention has become due for release under the Contract, follow it up promptly. Across several completed Projects, forgotten Retentions can add up to a significant amount of working capital.

Variations Can Create a Large Gap Between Project Revenue and Available Cash

Variation work commonly starts affecting Cash Flow before the corresponding revenue is received. Labour may already have been used. Subcontractors and Suppliers may already have been paid. Plant may have been hired and the additional work may be complete.

If the Variation remains unapproved, disputed or unpaid, the business is funding those costs.

For Cash Flow Forecasting purposes, there is an important difference between an approved Variation expected to be paid and a Variation that has merely been submitted. Keeping those figures separate makes the size of the exposure easier to see.

Why Can a Profitable Construction Project Still Use Cash?

Profit and Cash Flow measure different things. A Project can have a positive forecast margin but still require substantial working capital during delivery. Costs may be incurred weeks before the associated Progress Claims are received, while Retentions and unresolved Variations delay part of the Project revenue for much longer.

The amount of cash required can also change as the Project progresses. A labour-intensive or procurement-heavy period may consume considerably more cash than another stage of the same Project.

This is one reason a Project Cash Flow Forecast is useful alongside the Project budget and margin forecast.

Winning More Work Can Increase the Amount of Cash the Business Needs

A larger order book does not necessarily produce more available cash straight away. New Projects begin generating Labour, procurement, Plant and Subcontractor costs. Mobilisation and early Project expenditure may occur before the first substantial Progress Claims are received.

If several Projects reach that stage at the same time, the amount of working capital required can rise quickly.

Construction businesses planning significant growth should therefore forecast the cash required to deliver the work as well as the expected revenue and margin.

What Does a 13-Week Construction Cash Flow Forecast Show?

A 13-week forecast gives a short view of expected receipts, payments and available cash. For construction businesses, that period is long enough to capture several Progress Claim and payment cycles while remaining close enough for the underlying Project information to be reviewed regularly.

The forecast should not be treated as a figure prepared once and left unchanged. Progress Claim amounts move, payment dates change, Variations are approved or disputed and Project costs are updated.

Regularly replacing assumptions with current Project information makes the forecast more useful.

What if the Construction Cash Flow Calculator Shows a Shortfall?

A forecast cash shortage tells you where and when further investigation is required. Start with the Projects contributing to the shortfall. Check Progress Claims awaiting payment, Retention Moneys due for release, approved Variations, unresolved Variations and the timing of Project expenditure.

Then look at the business outside the Projects. Overheads, tax commitments, finance payments and other expenditure can also place pressure on available cash.

If the shortage continues even when reasonable payment timing assumptions are used, the problem may extend beyond collection timing. Project margins, WIP, cost overruns, Labour productivity, Overheads or the amount of working capital supporting the current order book may require closer review.

Need Help Working Through Your Construction Cash Flow?

A calculator can identify when a Cash Flow gap may occur. It cannot tell you why the gap exists.

Shannon Drew is a Management Accountant who often works with owners and decision-makers of construction businesses on Cash Flow Forecasting, Working Capital, Project financial reporting, WIP and the financial systems used to understand what is happening across the business.

Our Construction Financial Management and Cash Flow Services can be used where the figures in this calculator show there may be a problem that requires further investigation or ongoing financial management.

Call Shannon to discuss how he can help
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This article is intended for educational purposes only and does not contain legal or business advice. If you wish to engage Blaze Business & Legal to provide you with Legal Services and/or Business Advice that you can rely on, please contact us.

Rachelle Hare, Construction Lawyer, Business Adviser and Commercial Manager, Blaze Business and Legal
About the Author

Rachelle Hare

Construction Lawyer, Business Adviser and Commercial Manager|Blaze Business & Legal

Rachelle has more than 25 years of experience in construction law, business advisory, commercial management, contract administration and construction business structuring. Her career includes senior in-house legal roles at Tier 1 and Tier 2 construction companies including Thiess, Laing O’Rourke and Acciona, and private practice experience at top-tier law firms Corrs Chambers Westgarth and McCullough Robertson. She also spent over six years as a senior commercial manager on Defence and Tier 2 Construction and Technology Projects, including 8 months as Deputy Program Manager on a construction and technology program of National significance. At Blaze Business & Legal, Rachelle works alongside Shannon Drew to provide integrated construction law, financial management, commercial and business advisory services to construction businesses across Australia.

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Reviewed byShannon Drew, Management Accountant, Fractional CFO and Business Adviser, with 25+ years of construction industry experience.

Structure. Strategy. Systems. Success.

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