DIY projects fail when materials are mis-ordered. The right calculator before the trip to the store is the difference between one weekend and three.
Some calculations matter for a single decision; this one matters for years. DIY projects fail when materials are mis-ordered. The right calculator before the trip to the store is the difference between one weekend and three.
Wall area / coverage per litre. Add 10% for second coat and trim.
Room area × waste factor (10–15% depending on cut pattern).
Roll length × width vs wall area; mind the pattern repeat.
Volume (depth × area). Order 5% extra for compaction.
Floor/wall area × tile area; account for grout and breakage.
Linear feet vs board feet — they're different.
Can I trust the contractor's number? Cross-check with your own calculator. Both you and the contractor will be more accurate.
What's the most over-ordered material? Concrete. Pouring half a yard short costs more than ordering a full extra.
Run your own numbers before you trust a rule of thumb. Two minutes saves a lot of regret.