DIY

Concrete Slab Calculator

Built by Kevin Glover · @gloverbuilds · Verified formula

Calculate concrete for a slab by dimensions. Cubic yards, bags, and rebar spacing. Free calculator.

📅 Updated April 2026 ✅ Formula verified 📖 4 min read 🆓 Free · No sign-up

In this article

How to Use This Calculator
Tips for Best Results

O Cálculo

m³ = C × L × espessura (m). Laje de 6×3 a 10 cm: 1,8 m³ + 10% = 2 m³. Concreto atinge 70% da resistência em 7 dias, cura completa em 28. Não trafegue antes de 7 dias.

Espessuras

Calçada: 8-10 cm. Garagem: 12-15 cm. Laje com carga: 15-20 cm. Sempre sobre base de brita compactada de 10-15 cm.

⚡ CalcWolf Insight

Concrete reaches 70% of its strength in 7 days but needs 28 days to fully cure. Do not drive on a new driveway for at least 7 days. Walking is fine after 24-48 hours.

Frequently asked questions

Quanto para laje 3×3?▾

A 10 cm: ~1 m³. Usinado: R$400-600. Sacos: R$700-900.

Tempo de cura?▾

Caminhável: 24-48h. 70% resistência: 7 dias. Cura total: 28 dias.

✓ Math logic verified against primary sources → See our verification process

Kevin Glover · @gloverbuilds

Founder, CalcWolf · GLVTS · Blickr

All formulas sourced from primary references — IRS publications, peer-reviewed research, and official standards. Results are tested against independent reference calculators before publishing. Rates and brackets updated when official sources change. Editorial policy →