Margin of Error Calculator
Estimate the margin of error of a survey result from sample size, observed proportion, and confidence level.
Estimate the margin of error of a survey result from sample size, observed proportion, and confidence level.
Calculates flow velocity using the Hazen–Williams equation: V = 0.8492 × C × R_h^0.63 × S^0.54 (SI), where C is roughnes...
Convert between common units of energy including joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours,...
Calculates fill time = tank volume / flow rate. Supports litre, cubic metre, and US gallon inputs. Also computes net fil...
Calculates radiation pressure P_rad = I/c for a perfectly absorbing surface and P_rad = 2I/c for a perfectly reflecting...
Solve ax² + bx + c = 0 with real or complex roots, showing the discriminant along the way.
Compute the projection of vector A onto vector B in 3-D space: proj_B(A) = (A · B / |B|²) · B. Returns the projection ve...
Find the nth root of any positive number — square roots, cube roots, and any custom n you choose.
Compute the minimum sample size required to estimate a population mean within a target margin of error E at a chosen con...
Compute the number of ordered arrangements of length r drawn from a pool of n distinct items where repetition is allowed...
Compute the total flour, water, salt, and yeast needed for a target number of pizzas and dough-ball weight, using your c...
Compute the expected genotype frequencies (AA, Aa, aa) under Hardy-Weinberg equilibrium from a single allele frequency.
Every "X% of Y" problem, every "what percent of", every percent-change question — written out the way you'd actually say them.
Standard deviation is "average distance from the average". That one sentence covers 90% of everything you ever need to remember about it.