Cement Top Calculator 2025
Calculate the exact number of cement bags, sand, and ballast needed for your construction project. Supports slabs, foundations, plastering, and more with Kenya 2025 prices.
How Cement Calculation Works
Cement is mixed with sand and ballast (aggregate) in specific ratios for different applications. A common ratio for slabs is 1:2:4 (1 part cement, 2 parts sand, 4 parts ballast). This calculator uses wet-to-dry volume conversion (×1.54) and includes wastage to ensure you order enough materials.
Calculate Cement Requirements
Floor Slab (1:2:4): Structural floor slabs and driveways
Quick Reference - Cement Bags for Common Projects
Use this table to quickly estimate cement requirements for typical construction projects in Kenya. Based on 1:2:4 mix ratio with 10% wastage. For complete house construction estimates, see our construction cost calculator or cement for house calculator for specific house sizes.
| Project Description | Volume (m³) | Cement Bags | Sand (tonnes) | Ballast (tonnes) |
|---|---|---|---|---|
| 1 Room Floor (4m × 4m × 100mm) | 1.6 | 10 | 0.8 | 1.5 |
| 2 Bedroom House Slab (80m² × 150mm) | 12 | 75 | 6 | 11 |
| Foundation Strip (20m × 0.5m × 0.3m) | 3 | 19 | 1.5 | 2.8 |
| Driveway (6m × 3m × 100mm) | 1.8 | 11 | 0.9 | 1.7 |
| Column (0.3m × 0.3m × 3m) | 0.27 | 3 | 0.2 | 0.4 |
| Plastering (100m² × 15mm) | 1.5 | 12 | 1.2 | 0 |
Concrete Mix Ratios Guide - Kenya Standards
Different construction applications require different mix ratios. Using the correct ratio ensures structural strength and durability.
| Application | Ratio (C:S:B) | Strength Grade | Best For |
|---|---|---|---|
| Mass Concrete | 1:3:6 | M10 | Leveling, non-structural filling |
| Foundation/Slab | 1:2:4 | M15 | House foundations, floor slabs, driveways |
| Columns/Beams | 1:1.5:3 | M20 | Structural columns, beams, lintels |
| High Strength | 1:1:2 | M25 | Heavy-load structures, multi-storey buildings |
| Plastering | 1:4 | - | Internal & external wall rendering |
| Block Laying | 1:6 | - | Mortar for blocks and bricks |
Note: C:S:B = Cement:Sand:Ballast. For structural work, always consult a qualified engineer. Mix ratios may be adjusted based on aggregate quality and specific project requirements.
Cement Prices in Kenya 2025
Current market prices for 50kg cement bags from major manufacturers in Kenya. Prices may vary by region and retailer.
Bamburi Cement (50kg)
KES 750
Mombasa Cement (50kg)
KES 720
Savannah Cement (50kg)
KES 700
Simba Cement (50kg)
KES 730
National Cement (50kg)
KES 710
Athi River Mining (50kg)
KES 690
Buying Tips: Buy in bulk for discounts, compare prices from multiple suppliers, check for delivery options, and verify cement hasn't expired (check manufacture date).
Related Construction Calculators
Frequently Asked Questions - Cement Calculation
How many bags of cement do I need for a 1m³ concrete?▼
For a standard 1:2:4 mix ratio, you need approximately 6-7 bags of cement (50kg each) per cubic meter of concrete.
The exact calculation:
- Dry volume = 1m³ × 1.54 = 1.54m³
- Cement portion = 1.54 ÷ 7 = 0.22m³
- Cement weight = 0.22 × 1440 kg/m³ = 317kg
- Bags = 317 ÷ 50 = 6.3 bags (round to 7)
What is the best cement mix ratio for house foundation?▼
For residential house foundations in Kenya, the recommended mix ratio is 1:2:4 (Cement:Sand:Ballast), which produces M15 grade concrete. Use our construction cost calculator to estimate total building costs.
For larger structures or poor soil conditions, use 1:1.5:3 (M20 grade) for extra strength.
Important: Always consult a structural engineer for commercial or multi-storey buildings. See how many bags of cement you need for a complete house.
How much sand and ballast per bag of cement?▼
For a 1:2:4 mix, per 50kg bag of cement:
- Sand: ~80-100kg (about 2 wheelbarrows)
- Ballast: ~160-200kg (about 4 wheelbarrows)
- Water: ~25 liters (half bag weight)
For plastering (1:4): 200kg sand per bag, no ballast.
How thick should a floor slab be in Kenya?▼
Recommended slab thickness for different applications:
- Ground floor residential: 100-150mm
- Suspended floor slab: 150-200mm
- Garage/driveway: 150mm minimum
- Commercial buildings: 200mm or as per structural design
Always include reinforcement (BRC mesh or rebar) for suspended slabs.
Why add wastage to cement calculation?▼
Wastage accounts for materials lost during construction:
- Spillage: Cement spilled during mixing
- Over-excavation: Foundation trenches deeper than planned
- Uneven surfaces: More concrete needed for leveling
- Testing: Concrete cube samples taken
- Weather: Rapid drying requiring more water/mix
Recommended wastage: 5% for careful work, 10-15% for typical sites.
Pro Tips for Cement Work in Kenya
- Buy fresh cement: Check manufacture date - cement loses strength after 3 months
- Store properly: Keep bags off ground, covered from rain and moisture
- Mix correctly: Use clean water, proper ratios, and avoid adding too much water
- Cure adequately: Keep concrete moist for 7-14 days for full strength
- Consider machine mixing: More consistent than hand mixing for large projects
Important Disclaimer
General Information Only: This calculator provides estimates based on publicly available information and standard rates. Results are for informational and educational purposes only and should not be considered as professional financial, legal, or tax advice.
Accuracy and Updates: While we strive to maintain accurate and up-to-date information using official sources including Kenya Revenue Authority (KRA), National Social Security Fund (NSSF), Social Health Insurance Fund (SHIF), and other relevant government agencies, rates and regulations may change. Always verify current rates with official sources.
Seek Professional Advice: For specific tax planning, salary negotiations, financial decisions, or legal matters, please consult with qualified professionals such as certified accountants, tax advisors, financial planners, or legal practitioners who can consider your individual circumstances.
No Liability: Top Calculator and its operators accept no liability for any loss, damage, or inconvenience arising from the use of this calculator or reliance on its results. Users are responsible for verifying all calculations and information with official sources before making financial decisions.
Official Sources: For authoritative information, please refer to:
- Kenya Revenue Authority (KRA) - www.kra.go.ke
- National Social Security Fund - www.nssfkenya.co.ke
- Social Health Insurance Fund - www.sha.go.ke
Last updated: January 2025. This disclaimer applies to all calculators on Top Calculator.