Head Office Overheads Calculator

Compare the Hudson, Emden and Eichleay formulas on your own figures, side by side, with the working shown for each.

Updated: 26 September 2026. By Jack Butler-Kettle, Construction Claims Consultant.

Head office overheads are the costs of running your business that each job helps to pay for, such as offices, directors and insurance. When a job overruns, it can tie up your firm without earning more towards them.

Enter the period of delay from an extension of time, the extra time already granted or assessed for the delay. Working out the delay itself is a job for a programming expert. We do the money side only, with no delay analysis.

Work out the overheads

Count periods in

Use the same unit for every period below.

Your subcontract

Subcontract sum (£)

The original sum, without VAT.

Original subcontract period (weeks)

The period in your subcontract, before any delay.

Period of delay (weeks)

From the extension of time granted or assessed. We do not work out the delay itself.

For Hudson

Head office overheads and profit in your tender (%)

The percentage your tender added for them.

For Emden

Head office overheads and profit for the year (£)

From your company's accounts.

Turnover for the same year (£)

From the same accounts.

For Eichleay

Billings on this subcontract (£)

What you billed on it over its actual period.

Your total billings over the same period (£)

Across all your work.

Your head office overheads over the same period (£)

The actual costs, not a percentage.

Actual period of the subcontract (weeks)

From start to finish, including the delay.

The working

Hudson

Your tender percentage.

Enter your subcontract figures and your tender percentage.

Emden

The percentage from your accounts.

Enter your subcontract figures and the two figures from your accounts.

Eichleay

Your actual overheads, shared out by billings.

Enter the period of delay and the four Eichleay figures.

The formulas are an approximation, not a record of what you actually lost. A formula claim usually also needs evidence that the delay stopped you taking other work.

This is for guidance only. It works out the money for a delay already granted or assessed. It does not work out the delay.

How the formulas work

Hudson takes the head office overheads and profit percentage in your tender. It applies it to the subcontract sum per week, or per day, then multiplies by the period of delay.

Emden works the same way, but takes the percentage from your company’s accounts: total head office overheads and profit divided by total turnover.

Eichleay shares out your actual head office overheads by this subcontract’s share of your billings over the actual period. It divides that by the actual period of the work, then multiplies by the period of delay.

Each step is rounded as it is shown: money to the penny, and percentages to two decimal places. So the working adds up when you check it.

The formulas are an approximation, not a record of what you actually lost. A formula claim usually also needs evidence that the delay stopped you taking other work. The High Court said so in Walter Lilly & Company Ltd v Mackay, at paragraph 543.

Emden is the one most often accepted in UK practice. Hudson uses the figures in your tender, not your accounts. Eichleay comes from the United States.

Use your records first where they show the actual cost, such as director time spent on the delay. A formula fills the gap where the records cannot show the loss.

Sources

Walter Lilly & Company Ltd v Mackay & Anor [2012] EWHC 1773 (TCC) (High Court, Technology and Construction Court, 11 July 2012). The National Archives, Find Case Law.

If this is happening to you

Find the claim that fits, and the services that deal with it.

Delays and disruption are costing me. We organise delay records and prepare evidenced claims for the cost. See Delay & Disruption Claim.