Your Free Paint Calculator
Buying too much paint wastes money. Buying too little causes frustrating delays and extra trips. Get a reliable estimate in seconds so you can budget confidently and speak with contractors from a position of knowledge.
Pro Tip: For precise quotes on large or complex projects, a professional on-site measurement is always best. This calculator is your perfect starting point.
Get an accurate paint estimate based on surface type, condition, and real-world project data. We'll calculate coverage, wastage, and recommend the right packaging.
Total Surface Area:
0 m²
Base Coverage (No Coats/Wastage):
0 L
With 2 Coat(s):
0 L
Wastage Allowance (10%):
0 L
0x 20L Bucket
Standard professional grade
0x 4L Tin
Touch-ups & detail work
0x 1L Sample
Testing & final trim
Total packaged volume: 0L
Note: This calculation includes surface condition adjustments, color change factors, and realistic wastage allowance. For large commercial projects or textured surfaces, we recommend an on-site professional assessment for 100% accuracy. All figures are rounded to the nearest 0.5L for practical application.
Take this estimate to your preferred Octagon Paints marketer. Consider our Project Planning Guide for a full DIY checklist.
View Project Planning Guide ?Use this figure to understand the material component of contractor quotes. For an accurate, fixed-price quote, contact us for a free site assessment.
Get Free Assessment ?Multiply your estimated litres by the price per litre of your chosen paint brand to start building your project budget.
Browse Our Paint Products ?A professional paint calculator considers multiple factors, not just a generic coverage rate
| Factor | How It Affects Calculation | Octagon's Approach |
|---|---|---|
| Paint Type Coverage | Emulsion: 11 m²/L | Exterior: 9 m²/L | Enamel: 13 m²/L (NOT generic 12m²/L) | We apply actual coverage rates based on paint chemistry for each product type. |
| Surface Condition | New surfaces (+20%) | Weathered (+15%) | Primed (-5%) | Rough (+25-40%) | Surface roughness and smoothness directly affect paint absorption and coverage. |
| Color Change | Light to Dark (+15%) | Dark to Light (+20%) | Bold Change (+25%) | Drastic color changes require extra coats for proper coverage. We factor this in. |
| Number of Coats | Linear multiplier: 1 coat = 1x, 2 coats = 2x, 3 coats = 3x | Standard is 2 coats for most projects. Bare surfaces may need 3-4 coats. |
| Roller Absorption & Spillage | Additional 5% factored into calculation | Paint left in tray, on roller, and accidental spillage - we account for this. |
| Wastage Allowance | Retail: 10% | Contractor: 15% | For touch-ups, repairs, and color matching in future years. Contractors do multiple jobs. |
| Packaging Optimization | Converts to 20L buckets + 4L tins + 1L samples | Instead of just telling you 36L, we say "1 x 20L bucket + 1 x 4L tin + 4 x 1L samples" |
Common questions about our professional paint calculator
This professional calculator factors in:
Rough and textured surfaces absorb MORE paint than smooth ones. Our calculator automatically adjusts your coverage needs by 25-40% for rough surfaces. This prevents you from underestimating. Select "Interior Wall (Rough)" or "Exterior Wall (Rough)" and watch the calculation adjust.
Paint behavior changes dramatically based on surface condition:
That's why priming bare walls saves money long-term!
Our optimal packaging breakdown:
Instead of 36L (which doesn't exist as a single container), we recommend 1 x 20L + 1 x 4L + 4 x 1L. Easy to manage, no waste!
Retail (DIY): 10% wastage allowance
Contractor: 15% wastage allowance
Color change impacts paint needs:
Our calculator detects this and adjusts automatically. You might also need a tinted primer for color changes!
Yes! Our presets like "2BR Apartment (150m²)" and "3BR Bungalow (250m²)" are based on ACTUAL Octagon Paints installations in Kenya. They include realistic dimensions, door/window counts, and surface conditions. Use them as a starting point for similar projects.
That's exactly why we show packaging! If you calculate 36L, our tool converts it to practical containers:
1 x 20L bucket + 1 x 4L tin + 4 x 1L samples = 36L total
You now know exactly what to order without confusion. Walk into any Octagon outlet or shop knowing your exact requirement!
If reading this makes you think, "I'd rather have experts handle the measuring, buying, and painting..." you're not alone. Our team provides end-to-end service: precise measurements, professional-grade materials, and flawless application.
Explore more resources: All Resources | Project Planning Guide | Maintenance Guides