About TradeCalcs
Last updated: 12 August 2026
Free, fast calculators built around how UK trades actually buy materials and price work.
What this site is
TradeCalcs is an independent set of 28 calculators for the questions every building job starts with: how many bricks, how much concrete, how many tonnes of Type 1, how many rolls of turf, what pitch, what price. Every tool uses UK units and UK materials — 25kg and 850kg bulk bags, MOT Type 1, 215mm bricks, 440 × 215mm blocks, 20% VAT — because international converter sites do not know a bulk bag from a builder's bag, and merchant sites bury their coverage tables in PDFs.
Who makes it
TradeCalcs is built and maintained by an independent UK web developer who works with construction and trades businesses on their websites and local search. The calculators came directly out of that work: the same estimating questions kept coming up on real client projects, and the answers online were either wrong, buried, or written for the American market.
Where the formulas come from
Every calculator shows its working on the page — the formula, the assumed material dimensions or densities, and the rule-of-thumb conversions — so you can sanity-check the result rather than trust a black box. Assumptions follow standard UK conventions:
- Brickwork: 215 × 102.5 × 65mm bricks with 10mm joints, giving a 225 × 75mm coordinating face and 60 bricks per m² in a half-brick wall.
- Blockwork: 440 × 215mm blocks with 10mm joints, giving a 450 × 225mm coordinating size and exactly 10 blocks per m².
- Aggregates: published typical bulk densities — MOT Type 1 around 2.2 t/m³ compacted, gravel 1.6, sharp sand 1.7, topsoil 1.55 — with an 850kg bulk bag.
- Coverage rates: manufacturer-typical figures for paint, plaster, adhesive and insulation, stated openly so you can compare them against the tin or bag in front of you.
Where published figures across the industry disagree — and for mortar quantities they disagree wildly — we state our joint thickness and wastage assumptions explicitly rather than presenting a number with no derivation. Being the page that shows its working is the point.
What the results are, and are not
Results are ordering estimates. They are designed to get your materials order right to within a bag or two, so you neither run short mid-job nor pay to send a pallet back. They are not a structural specification and do not replace a structural engineer, building regulations approval, or your supplier's specific coverage figures for the exact product you are buying. Every page carries this reminder, and anything load-bearing should be confirmed by a qualified professional.
Corrections
If a figure looks wrong, we want to know. Email hello@tradecalcs.tech with the calculator name and the numbers you entered. Corrections take priority over new features, and the "last updated" date on each page reflects when it was last reviewed. Suggestions for new calculators are welcome too — several on this site exist because someone asked.
How the site is funded
TradeCalcs is free and funded by display advertising. There is no paid tier, no sign-up and no data collection — your calculations run entirely in your browser and are never sent anywhere. See the privacy policy for the detail.
Common questions
Who writes the calculators?
An independent UK web developer who builds websites for construction and trades businesses. The calculators came out of questions raised on real client projects.
Where do the formulas and densities come from?
Standard UK conventions, stated openly on every page — brick and block coordinating sizes, published bulk densities, and manufacturer-typical coverage rates. Where suppliers vary, the page says so.
How do I report an error?
Email hello@tradecalcs.tech with the calculator and the figures you used. Corrections come before new features.
Can I use these results for building control?
No — they are ordering estimates, not structural specification. Load-bearing and regulated work needs a structural engineer or building control sign-off.