Free calculators for UK trades.
Pick a calculator: CIS deduction, day rate, VAT, boiler sizing, concrete and aggregates, turf and topsoil, decking, fencing, and more. Plus a late-payment calculator below, for the invoice that's overdue right now.
Free tool
CIS deduction calculator
Work out exactly what's withheld from your next invoice.
Free tool
Day rate calculator
The floor you need to charge to actually pay yourself.
Free tool
VAT calculator
Add or remove VAT — and get the domestic reverse charge right.
Free tool
Missed calls & ROI tools
What missed calls cost you, and whether TradesInvo pays for itself.
Free tool
Radiator BTU calculator
The BTU output a room needs, by size, glazing and insulation.
Free tool
Boiler size estimator
A kW range to work from, based on bedrooms, bathrooms and radiators.
Free tool
System water volume calculator
Total system litres, and how much inhibitor to dose.
Free tool
Underfloor heating calculator
Pipe length and loop count, by area and spacing.
Free tool
Concrete volume calculator
Cubic metres and bag count for a slab, base or footing.
Free tool
Brick & block quantity calculator
How many bricks or blocks a wall needs.
Free tool
Screed, plaster & render coverage calculator
Bag count from area and thickness, for any of the three.
Free tool
Skip size estimator
The right skip yardage for the waste you're clearing.
Free tool
Turf & topsoil calculator
Turf rolls and topsoil volume from lawn area.
Free tool
Aggregate tonnage calculator
Tonnes of gravel, sand or MOT Type 1 from area and depth.
Free tool
Decking board calculator
Board count and linear metres from deck size.
Free tool
Fence post & panel calculator
Posts, panels and postcrete from a fence run.
Free tool
Late payment calculator
What a late-paying business customer legally owes you on top of the bill.
The unpaid invoice
The overdue invoice total.
Past your agreed payment terms.
Statutory interest = base rate + 8%. Check today's base rate on gov.uk.
You could claim on top
— interest plus £70 fixed compensation, by law.
Illustrative only — not legal or financial advice. Based on the Late Payment of Commercial Debts (Interest) Act 1998 (business-to-business). Fixed compensation £40 / £70 / £100 by debt size. Check the current base rate and your contract before acting.
Seen enough? Claim your patch.
TradesInvo captures every enquiry, replies first, and runs it to a booked, quoted, paid job. Early access is five founder slots per postcode — check yours.