Round numbers using 5 modes: round half up, banker's rounding, floor, ceil, and truncate. Shows step-by-step explanation with the digit being rounded. Numbers never leave your device — every calculation runs locally in your browser.
Calculate the number of ways to arrange k items from n items (nPr). Shows the step-by-step permutation calculation. Numbers never leave your device — every calculation runs locally in your browser.
Convert a Numerator/Denominator fraction to a 6-place decimal with percent and equivalents. Shows the decimal result directly. Numbers never leave your device — every calculation runs locally in your browser.
Calculate the factorial of any number (n!). Handles large numbers and shows the full multiplication sequence. Numbers never leave your device — every calculation runs locally in your browser.
Calculate Annual Recurring Revenue from subscription revenue, expansion revenue, and churn. Essential for SaaS businesses tracking growth. Numbers never leave your device — every calculation runs locally in your browser.
Calculate customer churn rate by dividing customers lost by total customers. Monitor retention health for your subscription business. Numbers never leave your device — every calculation runs locally in your browser.
Banker's rounding (round half to even) rounds exact .5 ties to the nearest even number: 2.5 → 2 and 3.5 → 4. Non-ties round normally (2.4 → 2). Use it for statistical and financial data to avoid upward bias.
Floor rounds toward −∞ (−3.7 → −4), ceil rounds toward +∞ (−3.7 → −3), and truncate simply drops decimals (−3.7 → −3). For positive numbers, floor = truncate. They differ for negative numbers.
It shows you exactly which digit is being rounded and why the result is what it is. For example, rounding 3.145 to 2 places: the third decimal digit is 5, so round-half-up rounds up to 3.15.
Round half up: everyday math. Banker's rounding: statistical/financial data. Floor: when you need the lower bound. Ceil: when you need the upper bound. Truncate: when you need to drop decimals without rounding (e.g., integer division).
Significant Figures Calculator
Round results to correct significant figures with rule explanations — 0.00450 has 3. Stop overstating lab precision — free, local, no signup.
Percentage Calculator
Computes X% of Y and what-percent-of-what (X is what % of Y) in two side-by-side panels with precise decimal arithmetic. Essential for everyday math — tips, discounts, tax rates, grade scores, and statistical comparisons where quick percentage answers are needed.
Last updated October 2026