Cycling through all six. Tap any point to stop.

Measured on six things

Free concrete yardage, bags & cost calculator.

Growth

A real problem with a specific wedge — multi-area combining, reserve control, ready-mix increments, and shareable estimates — that the single-shape Omni and vendor-tied QUIKRETE calculators don't match.

Screenshots

1 / 1

Concrete Calculator

About this app

Estimates finished concrete volume, bags, and optional material costs for slabs, footings, walls, columns, stairs, and ramps. Geometry estimates only—not structural design. No account required.

Key features

1Six shape calculators (slab, wall, round, tube, stairs, ramp) with multi-area combining and a 0–10%+ reserve control.
2Whole-bag counts by product yield plus optional ready-mix order increments and material cost totals.
3Step-by-step math breakdown with unit conversions, shareable project links, print, copy, and .txt export.

Target customer profile

Drawn from the product itself, not from a survey.

Demographic

DIY homeowners building patios, shed bases, or driveways

Pain points

Guessing bag counts, wasting money on too much mix, unit-conversion mistakes

Primary needs

Fast, accurate yardage and whole-bag counts with a safe reserve and cost total

Demographic

Concrete contractors and small remodel crews

Pain points

Inconsistent estimates across areas, supplier order increments, quoting speed

Primary needs

Multi-area combining, reserve control, ready-mix increments, and shareable estimates

Demographic

Landscape and hardscape designers planning pours

Pain points

Mixing US and metric specs, comparing bagged vs ready-mix costs

Primary needs

Unit flexibility, 3D preview, step-by-step math, and printable documentation

Scout Review

Written by AI from measured evidence, scored out of 100.

Concrete Calculator is a focused, fast, and genuinely useful estimator for slabs, walls, columns, stairs, and ramps. It nails the core job: enter dimensions, get cubic yards, whole bags, and optional cost, with a reserve you control and a step-by-step math breakdown that shows its work. The design is confident and trade-appropriate, the speed is excellent, and the multi-area plus ready-mix increment workflow is a real step up from the single-shape Omni and vendor-tied QUIKRETE calculators. The gaps are real but fixable: a 3D preview that shows almost nothing, small low-contrast secondary text, mixed ft/in inputs that invite mistakes, and a security posture missing CSP and email authentication. Accessibility is close but fails on contrast, touch targets, and label names. For a no-account tool aimed at DIYers and small crews, this is a strong, honest utility that does one thing well.

Measure by measure

Usability

Live-updating results, a clear shape selector, and a full step-by-step math breakdown make this genuinely easy to use. Mixed ft/in inputs and a guide buried below the calculator cost it points.

Design

Confident two-tone palette, strong hierarchy on the dark estimate panel, and a scannable guide. The 3D preview is mostly empty grey and secondary text is small and low-contrast.

Speed

Lighthouse mobile 98/100 with LCP 947ms and CLS 0.003; desktop 97/100. A lightweight single-page tool that loads instantly and updates without a hitch.

Security

HTTPS enforced with HSTS, frame protection, and a full header set (8/12 checks). No CSP, SPF, or DMARC, and shared links expose measurements and prices to anyone holding the URL.

Accessibility

Lighthouse a11y 93/100 with keyboard-rotatable 3D and US/metric units. Failing contrast, touch-target, and label-name audits keep it from the top of the band.

Growth

Improvement areas

3D preview is mostly empty pale grey with faint model and helper text; make it legible or shrink it.
Secondary text and captions fail contrast; touch targets are too small; some labels don't match accessible names.
Mixed ft/in inputs on one row invite mistakes; consider one unit per row or inline validation.
No CSP, SPF, or DMARC; shared links expose measurements and prices to anyone with the URL.

Design & Usability

The design is the strongest part of this tool. The near-black and rust palette on warm cream is disciplined and suits a construction audience far better than generic SaaS blue, and the dark 'Your estimate' panel with its 1.358 yd³ readout and Net/reserve/total breakdown makes the number feel trustworthy. The shape selector and segmented reserve control are clear. Where it slips: the 3D preview is a large pale-grey panel with a faint model and faint helper text, taking up real estate without earning it, and secondary text throughout the guide and estimate panel is small and low-contrast. Usability is solid — results update as you type, the step-by-step math section exposes every conversion and formula, and the CTA hierarchy (Share project over Print estimate over Copy/Download) is sensible. The mixed ft/in inputs on one row are the main risk, softened by the example line. The guide is deep but only reachable by scrolling past the calculator.

Speed & Security

Speed is the standout measured result: Lighthouse mobile 98/100 with LCP 947ms, CLS 0.003, and TBT 155ms, and desktop 97/100. For a single-page estimator this is exactly what you want — instant load, no layout shift, live updates that don't stutter. Security is competent but not exceptional: HTTPS is enforced with HSTS, frame protection, X-Content-Type-Options, Referrer-Policy, and Permissions-Policy all present, for 8/12 checklist points. What's missing is CSP, SPF, and DMARC — the last two matter less for a no-account tool, but the absent CSP is a real gap. The share-link model is transparent about its exposure (anyone with the link sees measurements and prices), which is the right call for a tool with no accounts. No SOC 2 or audit claims, which is normal at this stage.

Accessibility & Growth

Accessibility scores 93/100 on Lighthouse, which is strong, but the failing audits are the ones that matter for real users: insufficient color contrast (compounding the small secondary text), touch targets too small or tightly spaced, and visible text labels not matching accessible names. The 3D model does support keyboard rotation with arrow keys and Home to reset, and the tool offers US customary and metric units — both genuine positives. Growth is a judgment about the idea: the problem (guessing bag counts, wasting mix, unit mistakes) is real and the target customer is specific. The wedge over the listed alternatives is concrete — Omni Calculator is a broad multi-calculator with single-shape concrete estimation, and QUIKRETE's calculator is tied to their own bag yields. This tool adds multi-area combining, reserve control, ready-mix order increments, and shareable estimates in one place. That's a real differentiator, but the category is mature and the ceiling is a well-executed utility, not a platform.

Conclusion

If you're pouring a patio, a shed base, or a driveway and you're tired of guessing bag counts, this is a better starting point than the vendor calculator or a broad multi-tool site. It's free, needs no account, and the math is transparent. Go in with your measurements in one unit where you can, double-check the reserve, and treat the 3D preview as a rough sanity check rather than a design tool. The improvements that would move this from good to excellent are concrete: make the 3D preview actually render something legible, raise the contrast on secondary text, split mixed-unit inputs into a single unit per row, and add a CSP. None of those are hard, and the foundation is solid.

Suggestions for improvement

Make the 3D preview render a legible, well-lit model or shrink the panel — right now it's a large pale-grey area with faint content.
Raise contrast on secondary text (captions, 'Net concrete volume' rows, reserve notes) to meet WCAG AA.
Split mixed ft/in inputs into a single unit per row, or add inline validation that flags implausible thicknesses.
Add a Content-Security-Policy header and publish SPF/DMARC records for the domain.

How we score

Alternatives comparison

Named competitors, point by point. Nobody paid to appear here or to be left out.

	Concrete Calculator	Omni Calculator – Concrete Calculator	QUIKRETE Concrete Calculator
Shape coverage	Six shapes: slab, wall, round, tube, stairs, ramp	Common shapes (slab, footing, column, stairs)	Basic slab/footing shapes tied to QUIKRETE products
Multi-area combining	Yes — add multiple areas, combine, reserve applied once	No — single calculation per shape	No — single calculation per shape
Bag count by product yield	Yes — QUIKRETE 40/50/60/80/90 lb plus custom yield	Yes — generic bag yield	Yes — QUIKRETE product yields only
Ready-mix order increments	Yes — supplier increment rounding (e.g. 0.25 yd³)	No	No
Cost estimation	Yes — bag cost and ready-mix cost, multi-currency	Limited — generic cost per volume	No — product quantity only
3D preview	Yes — interactive, keyboard-rotatable (currently faint)	No	No
Account required	No — free, no account	No — free, no account	No — free, no account