Estimating & rates
- Tender Bid / No-Bid Score CalculatorScore a tender opportunity to decide whether to bid for it.
- Day Rate ↔ Salary Converter CalculatorConvert a salary to a day rate, or a day rate back to salary.
- All-In Labour Rate Build-Up CalculatorTurn an hourly wage into a true all-in charge rate.
- Markup / Margin / Sell Price CalculatorConvert between markup and margin, and find the sell price.
- Plant Rate Build-Up CalculatorBuild an hourly rate for owned plant from its real costs.
Valuation, payment & claims
- CIS Deduction CalculatorWork out the tax to deduct from a subcontractor payment.
- Variation / Dayworks Valuation CalculatorPrice labour, materials and plant on a daywork basis.
- Delay & Disruption Cost CalculatorEstimate what a delay has cost in time and resources.
- Interim Valuation & Application Summary CalculatorBuild an interim valuation and deduct the retention held.
- Late Payment Interest & Compensation CalculatorWork out interest and compensation owed on a late invoice.
- Loss & Expense CalculatorCompare the ways of valuing a prolongation claim.
- Retention & Cashflow CalculatorSee how much retention is held and when it gets released.
- VAT Domestic Reverse Charge CalculatorCheck whether a supply falls under reverse charge VAT.
Programme & performance
- Cash-flow S-curve CalculatorForecast monthly and cumulative value across a project.
- Earned Value CalculatorTrack cost and progress against the plan in one place.
- Procurement Lead TimeWork back from site dates to find order and approval deadlines.
- Resource / Labour Loading CalculatorFind the crew a target duration needs, or the time a crew needs.
- Subcontractor Performance ScorecardScore how a subcontractor performed across a package.
Conversion & measurement
About these contractor tools calculators
This set is commercial rather than technical - the calculations that decide whether a job makes money and when the money actually arrives.
Retention and valuation follow the JCT Standard Building Contract mechanics, including release of one half of the retention at Practical Completion and the cap at the contractual retention limit. Dayworks valuation applies the recorded labour, plant and materials with the contract percentage additions. CIS deduction applies the current HMRC rates for gross, net and unverified subcontractors. Measurement and cost planning reference RICS and NRM conventions.
Alongside those sit the estimating tools - markup and margin (which are not the same thing and are routinely confused), labour rate build-up from base wage to all-in charge-out, resource and labour loading across a programme, procurement lead times, and a bid/no-bid scoring aid.
They are aimed at estimators, quantity surveyors and contract managers in M&E and construction who want the arithmetic done consistently rather than in a spreadsheet that has been copied between jobs for five years.
Frequently asked questions
What is the difference between markup and margin?
Markup is the percentage added to cost; margin is the percentage of the selling price that is profit. A 20% markup on £100 gives £120 and a margin of 16.7%. Confusing the two is one of the most common causes of under-recovery, which is why the calculator shows both from whichever you enter.
Do the retention calculations follow JCT?
They follow the standard JCT SBC mechanics at clause 4.18 - retention applied as a percentage of certified value, capped at the retention limit, with one half released at Practical Completion and the balance at the end of the rectification period. Always check your executed contract, as amendments to these provisions are common.
Are the CIS rates current?
The calculator applies the standard HMRC Construction Industry Scheme rates for gross, net and unverified subcontractors, and shows which rate it used. Verify a subcontractor's status with HMRC before applying a rate in practice.