Your trusted free construction guide — built by engineers, used by everyone from DIY homeowners to professional contractors worldwide.
Our Mission – Making Construction Estimates Accessible to Everyone
concretesmath.com/ was built on a simple idea: the formulas, tables, and reference data that professional engineers use every day should be freely available to everyone — not locked behind expensive software subscriptions or buried in technical textbooks.
Whether you’re a structural engineer checking a quick volume estimate on site, a contractor pricing a footing pour, a student learning about concrete mix design, or a homeowner planning a shed base over the weekend — you deserve fast, accurate, and reliable resources that just work.
Every guide on this site uses the same industry-standard formulas referenced inACI 318, BS EN 1992 (Eurocode 2), and NHBC Standards. We don’t simplify the maths — we make it accessible. There’s a difference, and it matters when your project depends on the answer.
“Good construction starts with accurate numbers. We exist to make sure everyone has them.”
What We Believe In
Free Forever
No paywalls, no sign-up, no subscription tiers. Every guide, every guide, every table — free to use as many times as you need.
Accuracy First
Every formula is sourced from recognised engineering standards and peer-reviewed references. We cite our sources so you can verify everything.
Works Everywhere
Designed to work perfectly on phones on site, tablets in the office, and desktops in the design studio — no app required, no download needed.
Always Current
Our guides and guides are reviewed and updated annually to reflect the latest codes, standards, material densities, and best practice.
Our Story – How concretesmath.com/ Was Built
From a frustration on site to a trusted resource used across 50+ countries — here is how concretesmath.com/ came to be.
The Problem That Started Everything
Like many engineers, our founder found themselves on site repeatedly doing the same estimates by hand — concrete volumes, aggregate quantities, mix ratios — while also fielding questions from site teams and contractors who were using rough estimates or incorrect formulas. There had to be a better way. A free, reliable, instantly accessible resource that anyone could use from any device, without downloading anything or creating an account.
The First Guide Goes Live
The original concretesmath.com/ launched with a single concrete volume guide — a simple resource that estimated volume in m³ and weight in tonnes from basic rectangular dimensions. Within weeks, it was being shared in construction forums and WhatsApp groups by contractors and quantity surveyors who found it useful. The feedback was clear: people wanted more resources, more footing types, more aggregate options.
Expanding the guide library
We added the Aggregate Guide, Slab Guide, Cement Bag Guide, and Footing Guide in response to direct user requests. Each new resource was built following the same principles: standard engineering formulas, clear results, mobile-first design, and zero cost to the user. We also added wastage buffers, unit toggles between metric and imperial, and multiple material type options — the details that separate a useful resource from a great one.
Reference Guides and ACI Standards Coverage
We recognised that guides alone aren’t enough — users needed the context to understand why the numbers matter. We launched our comprehensive reference guides, including theACI Standards Guide 2026, theBeginner’s Guide to Concrete, and the Aggregate Reference Guide. These guides are written at an accessible level but reference authoritative sources throughout — the same information a structural engineer would use, in language anyone can understand.
concretesmath.com/ in 2026 — and What Comes Next
Today, concretesmath.com/ is used by engineers, contractors, quantity surveyors, students, and DIY homeowners across more than 50 countries. All data, densities, and code references have been reviewed and updated for 2026. We are actively developing new guides — including a rebar weight guide, a concrete mix design resource following ACI 211, and a pile foundation guide. If you have a request, we want to hear it — use ourContact Us pageto suggest what we should build next. For related background, see Contact.
Our Core Values – What Guides Everything We Build
Every decision about what to build, how to present it, and how to maintain it comes back to these four principles.
Accuracy Over Simplicity
We never round formulas to make them simpler if it means making them less accurate. Our guides use the exact same expressions found in ACI 318, BS EN 1992, and NHBC Standards — not approximations. If a result needs an explanation, we provide one. If you need to verify it, we point you to the source.
Accessible to Everyone
Construction knowledge should not be the preserve of those who can afford expensive software. Whether you’re a professional engineer in London, a self-build homeowner in Scotland, or a contractor in Pakistan using a phone on site — you get the same resources, the same accuracy, and the same zero cost.
Transparent and Referenced
Every formula we use, every density value, every code requirement is cited with its source. We don’t ask you to trust us blindly — we show you exactly where the numbers come from and link to the authoritative source so you can verify them yourself. Transparency builds trust.
Continuously Maintained
Construction standards, material densities, and building codes change. A guide built in 2020 and never updated may give you outdated results. We review every guide and guide annually, update them when standards change, and clearly display when content was last reviewed on each page.
Designed for Real Jobsites
Built on User Feedback
Almost every guide we have built was requested by a user. The wastage buffer feature, the imperial/metric toggle, the combined footing type, the ACI Standards Guide — all of these came from specific requests from engineers, contractors, and students who told us what they needed. We listen and we build.
What concretesmath.com/ Offers – Free Construction Resources & Guides
A complete suite of free construction guides and reference guides — covering concrete, aggregate, foundations, reinforcement, and code standards.
Concrete Volume Guides
Estimate concrete volume in m³ and weight in tonnes for slabs, columns, beams, footings, and any rectangular or circular element. Metric and imperial.
Footing & Foundation Guide
Pad footings, strip footings, and combined footings — with worked examples, minimum size tables, concrete grade guidance, and a full construction process guide.
Aggregate Guide
Estimate volume and weight for gravel, crushed stone, sand, Type 1 MOT, and recycled aggregate. 18 material types with 2026 bulk density values.
ACI Standards Guide 2026
The complete reference to ACI 318-19, ACI 301, ACI 308, ACI 211, and all major ACI codes — chapter by chapter, with exposure classes, strength tables, and inspection requirements.
Beginner’s Guide to Concrete
Everything a newcomer needs to know about concrete — from ingredients and hydration chemistry to mix ratios, pouring, curing, common mistakes, and safety. Includes an interactive quiz.
Rebar & Reinforcement Guide
Estimate reinforcement weight, total length, and bar quantities for slabs, beams, columns, and footings. Multiple rebar grades and bar sizes supported.
Slab & Driveway Guide
Concrete volume and reinforcement for ground-floor slabs, driveways, paths, patios, and suspended slabs. Includes sub-base quantity estimate.
Concrete Mix Design Guide
Step-by-step ACI 211.1 mix design — estimate cement, water, fine aggregate, and coarse aggregate proportions for any specified strength and exposure class.
Why Engineers & Contractors Trust concretesmath.com/
Four reasons professionals come back to concretesmath.com/ — and recommend it to their teams.
Engineering-Grade Formulas
Every estimate uses the exact expressions from ACI 318, BS EN 1992 (Eurocode 2), BS 8110, and NHBC Standards — not simplified approximations. The same formulas used in professional engineering software, delivered for free. For related background, see Home.
Cited Sources, Not Black Boxes
Unlike most online guides, we show you where every formula and every density value comes from. Links to ACI, BSI, and other authoritative sources are provided throughout — so you can check, reference, and cite the data in your own documents.
No Data Collection, No Accounts
We don’t require you to create an account, enter your email address, or agree to marketing emails to use any guide. Your inputs are processed entirely in your browser — nothing is sent to our servers. Your project data stays yours.
Built and Maintained by Engineers
concretesmath.com/ is built and reviewed by qualified structural engineers and construction professionals. When code editions change, when material densities are updated, or when a user identifies an error — we fix it. The site is actively maintained, not abandoned after launch.
Standards & References Behind Our Guides
Every formula, density value, and code requirement on concretesmath.com/ is sourced from recognised engineering standards. Here are the primary references we use. For related background, see Our Mission.
ACI 318-19
Building Code Requirements for Structural Concrete — the primary US and international standard for concrete design. Referenced throughout our footing, slab, and mix design guides.
ACI 211.1-91
Standard Practice for Selecting Proportions for Normal-Weight Concrete — the basis of our concrete mix design guide and mix ratio guidance.
ACI 308R-16
Guide to External Curing of Concrete — referenced in curing duration guidance across all our concrete guides and the Beginner’s Guide.
BS EN 1992-1-1 (Eurocode 2)
Design of Concrete Structures — the European equivalent of ACI 318, referenced in our exposure class tables, cover requirements, and concrete grade cross-references.
BS EN 206 / BS 8500
Concrete — Specification, Performance, Production and Conformity. Referenced in our concrete grade selection tables and mix design guidance for UK projects.
BS EN 1991-1-1 (Eurocode 1)
Actions on Structures — Densities, Self-Weight, Imposed Loads. The source of the 2,400 kg/m³ reinforced concrete density used in all our weight estimates.
NHBC Standards Chapter 4
NHBC Standards for foundations and ground floor construction — referenced in our strip footing minimum size table and foundation depth guidance for UK domestic buildings.
BRE Special Digest 1
Concrete in Aggressive Ground — the UK reference for sulfate design class (DS) classification, referenced in our concrete grade selection guide for footings and foundations.
Explore Our Free Construction Guides
All our resources are free, instant, and work on any device — no download, no sign-up, no cost.
Concrete Guide
Volume & weight for any element
Footing Guide
Pad, strip & combined footings
Slab Guide
Slabs, driveways & paths
Aggregate Guide
Gravel, sand & crushed stone
Cement Guide
Bags of cement for your mix
Rebar Guide
Reinforcement weight & length
Have a Question or a Suggestion?
We read and reply to every message. If you’ve found an error, want to request a new guide, or just want to say hello — we’d love to hear from you.