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Fileraz
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Fileraz
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Construction Calculator
Rule-of-thumb site math, reviewed October 2026 — first-pass material estimates, not a bill of quantities or a code check. Confirm with your contractor or engineer.
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Paint needed is wall area × coats ÷ coverage per litre, plus wastage: 100 m² with 2 coats at 10 m²/L and 10% waste needs (100 × 2 ÷ 10) × 1.1 = 22 litres — just over one 20 L pack, which the page flags for you. Coverage varies by paint and surface, so the tool takes the tin's figure instead of assuming one.
Read the spreading rate off the tin (fresh plaster and dark-to-light changes drink far more than a repaint at the same rate), set 2 coats for a solid finish or 3 for new work, and deduct large doors and windows from the area — or leave them in as a built-in buffer. Buy all packs together: tint varies between batches.
It does not subtract openings, price the job, or distinguish primer from topcoat coverage — check the tin's rate for each product and measure walls, not floors.
Rule-of-thumb coverage — verify on tin label.
Two is typical for a solid finish; new or strongly coloured walls may need three. Set the coats field accordingly.
No. Deduct large openings from the area yourself for a tighter estimate, or leave them in as a built-in buffer.
Two packs (40 L) with 18 L left for touch-ups — or one 20 L plus smaller packs if the shade sells in them. The page shows the pack count.
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