All calculators

Every tool on Dayob, grouped by topic. Each one includes a step-by-step guide and links to official references.

Construction & Landscaping

Cubic Yard CalculatorTurn the length, width and depth of any bed, trench or hole into cubic yards, then price the order before you call the supplier.Gravel CalculatorWork out the volume, weight and cost of gravel for a driveway, path, patio or drainage trench, with densities for the most common stone types.Square Footage CalculatorAdd up the area of one room or a whole floor plan, subtract what you will not cover, and see the result in square feet, square meters and square yards.Concrete CalculatorEstimate how much concrete to order for a slab, footing, post hole or set of steps, and how many premixed bags that would take.

Math

Ratio CalculatorSimplify any ratio, find a missing term, scale a recipe or mix, or divide an amount in a given ratio, with the working shown.Proportion CalculatorSolve a/b = c/d for any missing value with cross multiplication, and check whether two ratios are really in proportion.GCF CalculatorEnter two or more whole numbers to get their greatest common factor, least common multiple, prime factorizations and the Euclidean algorithm worked out.

School & Test Scores

AP Lang Score CalculatorEnter your multiple-choice result and your three essay scores to estimate your AP English Language and Composition score on the 1–5 scale.APUSH Score CalculatorPlug in your multiple-choice, short-answer, DBQ and LEQ results to estimate your AP United States History score from 1 to 5.Final Grade CalculatorFind out exactly what you need on the final exam to finish with the grade you want, and see the score needed for every letter grade.

Science

Molecular Weight CalculatorType a chemical formula to get its molar mass in g/mol, a breakdown by element with mass percent, and quick grams-to-moles conversions.

Fitness & Assessment

USMC PFT CalculatorScore your Marine Corps Physical Fitness Test by age group and sex, with event points, total score, class and pass or fail.Chronological Age CalculatorGet a child's exact age on the test date in years, months and days, the way assessment manuals calculate it, plus corrected age for babies born early.

Personal Finance

CD CalculatorSee what a certificate of deposit will be worth at maturity, how much interest it earns and how the balance grows over the term.401(k) CalculatorProject how your 401(k) could grow by retirement, including your employer match, raises and the 2026 IRS contribution limits.