Paint Calculator UK
Calculate paint quantities, primer & labour costs instantly
Professional Painting Calculator
Calculate paint quantities, labour costs & quotes for UK decorators and painters
Measure to nearest foot
Floor to ceiling height
For multiple surfaces
Typical: 15-25%
Textured needs more paint
Light colours need fewer coats
£15-25/m² typical
Insurance, fuel, etc
30-50% typical
🎨 Professional Painting Standards
- • Coverage rates: Smooth 12 m²/L, Textured 10 m²/L, Masonry 6-8 m²/L, Gloss 16-18 m²/L
- • Coat requirements: Light colours 1-2 coats, Mid-tone 2-3 coats, Dark 3-4 coats minimum
- • Always prime: New plasterboard, patched areas, glossy surfaces, colour changes
- • Wastage factor: Standard 10% for errors and obstacles
- • Labour rates: £15-25/m² UK average (varies by experience)
- • Drying time: 4-8 hours between coats, 24 hours before heavy use
- • Overhead: Budget 10-15% for insurance, fuel, marketing, equipment
- • Profit margin: 30-50% typical for profitable jobs
Paint Quantity & Cost Calculation Formula
Professional painting calculations require accurate surface area measurement, coverage rate selection, wastage accounting, and comprehensive cost estimation including materials, labour, overhead, and profit margins.
Paint Calculation:
Total Paint = (Paintable Area × Number of Coats ÷ Coverage Rate) × (1 + 10% Wastage)
Job Cost Estimation:
Client Price = (Materials + Labour + Overhead) × (1 + Profit Margin)
This calculator automatically includes surface area calculations (subtracting doors/windows), applies correct coverage rates by surface type, factors in wastage (10%), calculates primer requirements separately, determines labour costs per m², adds overhead costs (insurance, fuel, marketing), and applies your desired profit margin for accurate professional quoting.
Understanding Paint Coverage & Calculations
Professional painting requires accurate material estimation based on wall area, surface type, colour intensity, and number of coats. This calculator helps you calculate exact quantities of paint, primer, and labour costs based on UK industry standards. Understanding the relationship between coverage rates, surface conditions, and colour depth is essential for accurate quoting and preventing project shortages.
Key principle: Smooth surfaces (12 m²/L) require less paint than textured surfaces (10 m²/L). Dark colours need 3-4 coats minimum for uniform coverage, while light colours typically need only 1-2 coats. Always prime new plasterboard and patched areas to seal porosity and prevent premature topcoat drying, which ensures better coverage and finish quality. Wastage factor (10%) accounts for overspray, brush waste, and obstacles.
Paint Coverage Rates by Surface Type
Emulsion/Latex Paint
- • Smooth plaster: 12-14 m²/litre
- • Textured surface: 8-10 m²/litre
- • Drywall: 12-13 m²/litre
- • Primer: 14-16 m²/litre
- • Standard for walls & ceilings
Oil/Gloss Paint
- • Gloss finish: 16-18 m²/litre
- • Satin finish: 14-16 m²/litre
- • Primer: 13-15 m²/litre
- • For woodwork & trim
- • Longer drying time
Masonry/Exterior Paint
- • Brick/block: 6-8 m²/litre
- • Porous surfaces: 5-7 m²/litre
- • Rendered: 7-9 m²/litre
- • Higher absorption
- • Seal porosity with primer
Primer Options
- • Universal primer: Most surfaces
- • Bonding primer: Gloss/glossy
- • Sealer primer: New plaster
- • Stain blocker: Water stains
- • Always use on new work
Colour & Coat Requirements
Number of Coats by Colour
- ✓ White/Light: 1-2 coats
- ✓ Pale shades: 1-2 coats
- ✓ Mid-tone: 2-3 coats
- ✓ Bold colours: 3 coats
- ✓ Dark shades: 3-4 coats
- ✓ Black/Navy: 4+ coats
Application Best Practice
- ✓ Always apply primer first
- ✓ 4-8 hours drying between coats
- ✓ Maintain wet edge to avoid lap marks
- ✓ Sand lightly between coats
- ✓ Check coverage with 2nd coat
- ✓ Apply thin, even coats
Surface Preparation & Professional Tips
Surface Preparation
- ✓ Clean all dust & dirt
- ✓ Fill holes with quality filler
- ✓ Sand rough areas smooth
- ✓ Prime new plasterboard
- ✓ Use undercoat for colour changes
- ✓ Check surface is fully dry
Professional Application
- ✓ Use correct brush/roller type
- ✓ Apply thin, even coats
- ✓ Maintain wet edge always
- ✓ Work top to bottom on walls
- ✓ Sand between coats (fine grit)
- ✓ Allow full drying time between coats
Frequently Asked Questions
Q: How do I calculate exact surface area with doors and windows?
Subtract approximately 20% from total wall area. For precise calculations: standard door (1.9m × 0.9m = 1.7m²), window (1.5m × 1m = 1.5m²). Enter your percentage in the calculator to automatically subtract openings from paintable area.
Q: Why is the 10% wastage factor included?
Wastage accounts for: overspray on walls, paint remaining in brushes/rollers, obstacles requiring repainting, natural coating variations, and safety margin to prevent shortages mid-project. Industry standard is 10-15% wastage for indoor painting.
Q: Why do dark colours need more coats?
Dark pigments are more transparent than light pigments. Multiple thin coats build opacity gradually - rushing into thick coats causes sagging, drips, and uneven drying. Always apply 3-4 thin coats rather than fewer thick coats for professional results.
Q: Is primer always necessary?
Yes. Always use primer on: new plasterboard (very porous), patched areas (filler is porous), glossy/previously painted surfaces (poor adhesion), and when making dramatic colour changes. Primer seals porosity, prevents staining, and ensures topcoat adhesion.
Q: How should I budget for overhead and profit?
Overhead (10-15% of labour) covers: insurance, fuel, vehicle maintenance, marketing, admin. Profit margin (30-50%) covers: business growth, contingencies, weather delays, emergency repairs. Total client price = (Materials + Labour + Overhead) × (1 + Profit Margin).
Q: What drying times should I allow between coats?
Standard emulsion paint requires 4-8 hours drying time between coats (check manufacturer specs). Gloss paint typically takes 16-24 hours. Allow additional time in cold temperatures (below 10°C) or high humidity (above 70%). Never rush drying - premature second coat application causes adhesion failure.
✓ Professional Quality Assurance
This calculator provides professional estimates based on UK paint manufacturer specifications, industry-standard coverage rates, and proven cost calculation methodologies. Coverage rates vary by paint brand, substrate condition, application technique, and environmental factors - always confirm specifications with your paint supplier. Proper surface preparation and environmental conditions (10-25°C, 35-65% humidity) are critical for professional results. For best quality, use premium paints from reputable UK manufacturers. Always order extra paint (10-15%) for waste and future touch-ups. Keep detailed notes on paint batch numbers for consistent colour matching on future projects.
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Complete Your Trade Calculations
Use our comprehensive suite of professional estimators: Plaster Calculator for surface prep, Brick & Block Calculator for masonry, Tiling Calculator for finishes, and view all calculators to build complete project estimates and quote confidently.
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