Circle Area Calculator

Calculate what percentage one number is of another number, plus the remaining amount and decimal ratio. Use this percentage calculator for grades, discounts, progress, budgets, survey results, inventory, and everyday comparisons.

Calculate the amount of increase, percentage increase, and change multiplier between an original value and a new value. Use it for prices, revenue, wages, traffic, inventory, measurements, and performance comparisons.

Calculate the amount of decrease, percentage decrease, and percentage remaining between an original value and a new value. Use it for sale prices, budget reductions, inventory decline, weight change, usage reduction, and performance comparisons.

Calculate reduced fraction results, decimal values, and percentages for addition, subtraction, multiplication, and division. Enter two fractions and select an operation for homework, recipes, measurements, proportions, or everyday math.

Calculate the arithmetic mean, sum, count, minimum, and maximum of a list of numbers. Paste comma-separated, space-separated, semicolon-separated, or line-separated values for grades, costs, measurements, scores, and reports.

Calculate estimated single-phase amps from watts, voltage, and power factor. Use this watts to amps calculator to compare load-current scenarios while confirming equipment ratings, circuit protection, and applicable electrical rules separately.

Calculate estimated single-phase watts, kilowatts, and volt-amperes from amps, voltage, and power factor. Use this amps to watts calculator to understand a load scenario before relying on nameplate data and qualified electrical design.

Calculate estimated single-phase amps from kilowatts, voltage, and power factor. Use this kW to amps calculator for transparent power-current scenarios, then confirm the actual installation with equipment data and qualified electrical review.

Calculate estimated single-phase amps and volt-amperes from kVA and voltage. Use this kVA to amps calculator to compare apparent-power scenarios, then confirm system phase, equipment ratings, and electrical design requirements separately.

Calculate estimated single-phase kilowatts, watts, and apparent power from amps, voltage, and power factor. Use this amps to kW calculator for a transparent load estimate before checking nameplate data and qualified electrical design requirements.

Estimate single-phase or three-phase voltage drop from voltage, current, one-way conductor length, and resistance per 1,000 feet. Use this voltage drop calculator for planning only and have a qualified electrician verify a real electrical design.

Calculate both, either, exactly one, neither and conditional probabilities for two events. Use independent events or enter a known intersection for dependent events.

Add or subtract hours, minutes, and seconds with clear carry handling and signed results. This free time calculator works with durations longer than a day.

Estimate sunrise, sunset, and daylight for a chosen date, coordinates, and explicit UTC offset. Handles high-latitude days without a sunrise or sunset.

Calculate age in years, months, and days for any as-of date. See total elapsed days and the next birthday, with explicit February 29 handling.

Compare your observed daily calorie intake with estimated maintenance calories to see an arithmetic deficit or surplus. Adult-only educational estimate, not a diet prescription.

Calculate an adult bedtime from your desired wake time, or a wake time from bedtime. Include expected time to fall asleep, with age-aware CDC guidance and no sleep-cycle promises.

Estimate adult maintenance calories and resting energy from age, equation coefficient, height, weight, and typical activity using Mifflin-St Jeor. No weight-loss target or diet plan.

Calculate the circumference of a circle from its radius or diameter. Convert results among millimeters, centimeters, meters, inches, and feet with a live formula check.

Calculate right circular cylinder volume from radius or diameter and height. Convert cubic meters, liters, cubic centimeters, cubic feet, cubic inches, and US gallons.

Calculate triangle area from base and perpendicular height or three side lengths using Heron’s formula. Convert between square metric and US customary units with validation.

Convert running distance and elapsed time to pace per kilometer, pace per mile, speed, and constant-pace 5K to marathon finish times.

Calculate baseball OPS, OBP, SLG, and singles from at-bats, hits, extra-base hits, walks, hit by pitch, and sacrifice flies.

Estimate one-rep max using the Epley equation from a completed set. View 60%–95% reference loads in kilograms or pounds with limitations explained.

Find a line equation in point-slope form from one point and a slope or from two points. See substitution steps and the special vertical-line equation.

Compare two numbers with a symmetric percentage difference using the average of their absolute magnitudes. See the formula, zero case, and how it differs from percent change.

Calculate slope, rise, run, inclination angle, and point-to-point distance from two coordinates. Detect vertical undefined slope and identical-point input.

Calculate the area inside a circle from radius or diameter, then convert square meters, centimeters, millimeters, feet, and inches with a live formula check.

Find volume for a box, cylinder, sphere, or cone from measured dimensions. Convert cubic metric or US customary units, liters, and US liquid gallons instantly.

Solve every side of a 30-60-90 right triangle from the short leg, long leg, or hypotenuse. See perimeter and area with independent length and square units.

Estimate adult body-fat percentage with the published relative fat mass equation using height, waist, and study coefficient. Metric or imperial inputs; not a diagnosis.

Calculate formula-predicted adult resting energy expenditure with Mifflin-St Jeor using age, weight, height, and original study coefficient. Not measured basal rate or an intake target.

Convert walking steps to international miles using a known one-step length or a clearly labeled height-based estimate. Check exact units, examples, and gait limitations.