Quick time-related cost estimate for delays and disruption.
Internal order-of-magnitude figure. Formal claims need substantiation (records, programmes, correspondence).
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About this delay & disruption cost calculator
This free delay & disruption cost calculator produces a quick, order-of-magnitude estimate of the time-related cost of a hold-up on site. You enter the delay duration in weeks, your working pattern (days per week and site hours per day), the affected headcount and labour rate, plus weekly time-related costs and any one-off rework, and it returns the indicative financial impact with a full component breakdown. It is built for UK building-services engineers, contractors and subcontractors who need a fast internal figure to gauge the scale of a disruption before commissioning detailed work.
How the cost is estimated
The estimate has four parts. Labour disruption is site hours × labour rate × an idle/disruption factor, where site hours are weeks × working days per week × hours per day, and the factor scales from 100 % (fully idle) down to a partial figure such as 30 % (partially disrupted). Time-related costs sum the weekly site prelims, supervision/PM and plant or hire extension, multiplied by the number of weeks. Any rework or abortive works are added as a one-off, and an optional overheads & profit (OH&P) percentage is applied to the subtotal. The methodology is adapted from the Society of Construction Law (SCL) Delay & Disruption Protocol (2nd ed., 2017) measured-mile principles.
Frequently asked questions
What does the idle/disruption factor mean?
It is the proportion of the affected labour time that is lost. Set it to 100 % when the workforce is fully idle, or lower, for example 30 %. When work continued but at reduced productivity.
Can I use this figure in a formal claim?
No. It is an internal, order-of-magnitude estimate only. Formal claims require substantiation with programmes, daily records and correspondence, and should be verified with a qualified quantity surveyor or claims consultant.
What should the labour cost rate include?
Use an all-in rate covering wages plus oncosts. The calculator applies it per site hour across the affected headcount for the delay period.