Resources & How-To Guides
Short, practical guides that show the math behind our tools — with real examples you can follow. Read the guide, then let the matching calculator do the work.
Home & GardenHow much paint do I need for a room?Work out how much paint a room needs: a wall-area formula, a worked 12x12 example at about 2 gallons, coverage figures, and the mistakes that waste paint.Read guideFinanceHow long will it take to pay off a credit card?How long to pay off a credit card: the payoff formula, why interest slows you down, and a worked 5,000 dollar example at 22 percent APR. Estimates only.Read guideConstructionHow much concrete do I need for a slab?Calculate concrete for a slab: multiply length by width by thickness in feet, divide by 27 for cubic yards, then add about 10 percent for waste.Read guideHome & GardenHow to calculate square footageCalculate square footage by multiplying length by width in feet. Convert inches to decimal feet, split L-shaped rooms into rectangles, and add the areas.Read guideHome & GardenHow much mulch do I need?Mulch depth in inches divided by 12, times bed area, gives cubic feet. Divide by 27 for yards or by 2 for standard bags. Worked example inside.Read guideHome & GardenHow much flooring do I need?Work out how much flooring to buy: room square footage times one plus a waste fraction, divided by box coverage, rounded up. Free calculator and worked example.Read guideFinanceHow to convert hourly pay to an annual salaryConvert hourly pay to a yearly salary with one simple formula, full-time and part-time examples, and how gross pay differs from your take-home.Read guideBusinessHow to calculate profit marginCalculate profit margin: subtract cost from revenue for profit, then divide profit by revenue. Includes a worked example and how margin differs from markup.Read guideAutoHow much will my road trip cost?Road trip cost = fuel plus lodging, food, tolls, parking, and activities. See the formula, a worked 1,200-mile example, and why gas is rarely the biggest cost.Read guidePlanning ToolsMoving checklist: what to do before moving dayA moving checklist counted back from moving day: research and declutter at 8 weeks, confirm the mover and transfer utilities at 2 weeks, pack last.Read guide