About CalcTools.uk
CalcTools.uk is a free collection of construction and home improvement calculators built specifically for the UK market. Every calculator uses metric measurements, standard UK material sizes, and British building terminology.
Why We Built This
Most online construction calculators are designed for the American market. They use imperial measurements, US material sizes (4x8 ft drywall instead of 2400x1200mm plasterboard), and American terminology. UK builders and DIYers deserve better.
We also noticed that no calculator site shows you where the waste comes from. They just say "add 10% for waste" without explaining why. Our visual waste diagrams show the actual cutting layout so you can see exactly how many full sheets you need, where cuts are required, and what gets thrown away.
What Makes Us Different
- UK standard sizes: 215x102.5x65mm bricks, 2400x1200mm plasterboard, 25kg cement bags, 2.5L and 5L paint tins
- Visual waste diagrams: see exactly where every piece goes
- Real cutting patterns: actual sheet layouts, not just "area plus 10%"
- 100% free: no signup, no premium tier, no limits
- Privacy-first: all calculations run in your browser, nothing stored on our servers
How We Source Our Figures
Where a real formula exists, we calculate from it instead of falling back to a single flat number. Our close board fence calculator, for example, works out boards per metre from whatever board width and overlap you actually enter, rather than quoting one "boards per metre" figure that's only correct for one specific board size.
Where no formula exists, such as a material's bulk density or a settling allowance, we use a sourced industry figure and say so on the page, rather than presenting an assumption as fact. Where a calculator cites a British Standard or a Specification for Highway Works clause, we've checked what that document actually says rather than repeating a citation found elsewhere - see our standards reference for the ones we've verified so far.
We also check our own numbers after they ship, not just when we first write them, and keep a public backlog of defects we've found and fixed in our own figures. See our full methodology page for the detail.
Who's Behind CalcTools.uk
CalcTools.uk is built by Dan, who works in construction and is based in Hampshire.
The first calculators were built for my own use, to save time working out materials for real jobs. Once they were saving me time, it made sense to tidy them up and put them online so other tradespeople and DIYers could use them too.
That's why everything here is built around the way materials are actually sold in the UK: standard sheet sizes, 25kg bags, UK tin sizes and merchant pack quantities. If a figure doesn't match what you see on site, please let me know via the contact page.
Who This Is For
Whether you're a professional tradesperson working on site or a DIY enthusiast tackling a weekend project, CalcTools.uk helps you calculate exactly what materials you need before heading to the merchant. Stop guessing, stop overbuying, stop running out halfway through a job.
Contact
Got a suggestion for a new calculator or found a bug? We'd love to hear from you. See our contact page or email us directly at hello@calctools.uk.