CalcThis Blog

Calculate the exact cubic yards and tons of gravel for any driveway — with depth recommendations, coverage tips, and a free calculator.

Find out exactly how many cubic yards or bags of mulch to order for any garden bed or yard area, at the right depth.

Calculate cubic yards of topsoil for lawn repairs, raised beds, or new gardens — including how deep to go and what that weighs in tons.

Calculate cubic yards of concrete for slabs, footings, and columns — with bag counts, mix ratios, and thickness recommendations.

Work out cubic yards or tons of sand for any project — paver bases, sandbox fills, concrete mixes, or levelling — with depth and coverage explained.

Turn room square footage into boxes to buy — with the right waste factor for your material and layout, plus underlayment and a cost estimate.

The exact formulas for rectangles, circles, triangles and irregular rooms — plus square yard and acre conversions, and how much extra to order for waste.

The riser-height formula, standard vs. flush stringer mounts, the Pythagorean stringer-length formula, and the building-code numbers every staircase has to meet.

Reading the fraction marks, finding a common denominator, carrying and borrowing an inch, and converting to decimal or millimetres — with worked examples.

A four-step walkthrough: find your TDEE, set your goal, hit your protein target, then divide fat and carbs. Includes a worked example and free calculator.

Learn what Zone 2 training is, how to calculate your exact heart rate range by age, and why it's the most effective zone for building your aerobic base.

Learn the Epley and Brzycki formulas, how to estimate your 1RM safely from a submaximal set, and how to use training percentages to programme every goal from strength to hypertrophy.

Learn the Navy tape method, how body fat compares to BMI, healthy ranges by age and sex, and how calipers, BIA, and DEXA stack up on accuracy.

Estimate your BMR with the Mifflin-St Jeor equation, apply the right activity multiplier, and turn the number into calorie targets for losing, maintaining, or gaining weight.

The BMI formula in metric and imperial, a worked example, the WHO weight categories, how to turn your number into a healthy weight range, and where BMI falls short.

Find your maintenance calories, subtract a safe deficit, respect the minimum floors, and adjust as the scale moves — with a worked example and the truth about the 3,500-calorie rule.

Your healthy weight isn't one number — it's a range. How to find yours from your height, what the Robinson, Devine, Miller and Hamwi formulas add, and where to aim inside it.

What VO2 max measures, two ways to estimate it at home, what counts as good for your age and sex, and how it connects to your race pace.

The real answer isn't a flat 2,000 steps — it depends on your height. The stride-length formula, a height-based reference table, and what common step counts add up to in distance.

The RDA is a floor, not a target. The four goal-based ranges, why age and sex change the number, total weight vs. lean body mass, and how to spread it across meals.

The exact formula if you know your body fat %, the Boer/James/Hume estimate formulas if you don't, what counts as a healthy range, and why the scale alone can't tell fat loss from muscle loss.

What WHR actually measures, exactly how to measure your waist and hips, the WHO risk bands by sex, a full worked example, and how it compares to BMI.

The two methods that work by hand — count forward, or subtract day-numbers — plus whether to include the end date, weeks and months, business days, and the leap-year traps.

Work out your age in years, months, and days by hand with the borrow-and-subtract method — plus age in total days, and the leap-year edge cases that trip people up.

The formula, a full worked example with exam grades, what to use as a weight, and how it's different from the simple average you learned in school.

Six ways to curve a class's scores — add points, scale to the highest grade, percentage boost, bell curve, square root, and target-mean — with the formula, a worked example, and which one to use.