🧮Calculators
Calculators cover finance, health, math, physics, engineering and everyday life: interest and loans, net salary, BMI, rule of three, conversions and more. Results are informational and educational — for important decisions, confirm with a professional and official sources.
2826 tools
Mexican Food Calories
Estimates calories of common Mexican dishes (taco, burrito, guacamole) from grams.
Star Luminosity Calculator
Estimates star luminosity from radius and temperature using Stefan-Boltzmann.
Parallax Distance Calculator
Computes parsec distance of an astronomical object from its parallax in arcseconds.
Resistor Power Dissipation
Computes power dissipated by a resistor from V*I or V^2/R.
RLC Series Impedance
Computes total impedance Z of a series RLC circuit from R, L, C, frequency.
Battery Series & Parallel Calculator
Calculate the total voltage and capacity when wiring batteries in series or in parallel. See how each setup changes the volts and amp-hours of the pack.
Battery Charge Time Calculator
Estimates charge time of a battery from capacity in mAh and charge current in mA.
Solar Panel Efficiency
Computes solar panel efficiency from output power, irradiance, and area.
Vehicle Braking Time
Computes braking time and distance from speed and deceleration.
Circular Orbital Velocity
Computes circular orbital velocity at a given altitude above Earth using v = sqrt(GM/r).
Reading Time by Speed
Estimates text reading time from word count and reading speed in WPM.
Marathon Time Calculator
Estimates total marathon time from average pace in minutes per kilometer.
Bar Duration from BPM
Calculates the duration in seconds of a music bar (4/4, 3/4, 6/8) given the BPM.
Beat Duration in ms
Converts BPM into milliseconds per beat for DAW delays, sequencers and loops.
Musical Note Frequency
Computes the frequency in Hertz of any note from the semitone distance relative to A4=440 Hz.
Cents Between Frequencies
Calculates the interval in cents between two frequencies using 1200·log2(f2/f1).
Pitch Shift Semitones to Frequency
Computes the resulting frequency when shifting a pitch by N semitones via f·2^(n/12).
RT60 Decay (Sabine) for Music
Computes the RT60 decay time in seconds using Sabine V·0.161/A — handy for rehearsal rooms.
Speed of Sound by Temperature
Calculates the speed of sound in air (m/s) versus Celsius temperature using 331.3+0.606·T.
Echo Time by Distance
Computes the round-trip time of a sound echo in seconds given the distance and air temperature.
Mixer Pan L/R Balance
Computes the linear gain on each channel (L/R) when moving the pan fader on the mixer.
Kinetic Energy (J)
Calculates kinetic energy in joules given mass in kg and velocity in m/s via 0.5·m·v².
Gravitational Potential Energy
Calculates Ep=m·g·h in joules from mass, height and gravitational acceleration.
Spring Elastic Energy
Calculates the elastic energy stored in a spring E=0.5·k·x² in joules from constant and deformation.
Mechanical Power from Work
Calculates mechanical power P=W/t in watts from work in joules and time in seconds.
Moment of Inertia (Solid Cylinder)
Computes I=0.5·m·r² for a solid cylinder spinning about its central axis.
Moment of Inertia (Solid Sphere)
Computes I=0.4·m·r² for a solid sphere spinning about an axis through its center.
Angular Momentum L=I·ω
Calculates angular momentum L in kg·m²/s from moment of inertia I and angular velocity ω in rad/s.
Torque from Force and Distance
Calculates torque τ=F·d·sin(θ) in N·m from applied force, lever arm and angle.
Coefficient of Restitution
Calculates the coefficient of restitution e=(v2-v1)/(u1-u2) for two bodies before and after collision.
Free Fall Time
Calculates the time of free fall from height h via t=sqrt(2·h/g).
Projectile Range (Flat Ground)
Calculates the horizontal range R=v²·sin(2θ)/g of a projectile on flat ground with no air drag.
Thin Lens Focal Length
Computes focal length f via 1/f=1/o+1/i from object and image distances in centimeters.
Snell Refraction Angle
Calculates refraction angle via n1·sin(θ1)=n2·sin(θ2) for light crossing two media.
Fluid Pressure by Depth
Calculates hydrostatic pressure P=ρ·g·h in pascals from fluid density and depth.
BMI for the Elderly (60+)
Calculates BMI with PAHO classification specific for the elderly — normal range 22–27 kg/m².
eGFR (MDRD)
Estimates GFR via simplified MDRD using serum creatinine, age, sex and ethnicity.
eGFR (CKD-EPI 2009)
Estimates GFR with the CKD-EPI 2009 equation — current standard for chronic kidney disease staging.
Blood Pressure Classification
Classifies systolic/diastolic blood pressure following Brazilian hypertension guidelines.
Normal Respiratory Rate by Age
Shows the normal RR range (breaths per minute) for newborn, infant, child and adult.
Normal SpO2 by Context
Shows normal SpO2 ranges for healthy adult, COPD and altitude — quick reference for nursing.
Bicarbonate in Acid-Base Balance
Estimates HCO3 using the Henderson-Hasselbalch equation from pH and pCO2.
Serum Anion Gap
Calculates the anion gap AG=Na-(Cl+HCO3) in mEq/L to investigate metabolic acidosis.
Pediatric Paracetamol Dose
Calculates paracetamol dose in mg/kg for children (10–15 mg/kg/dose, max 75 mg/kg/day).
Pediatric Amoxicillin Dose
Calculates amoxicillin dose in mg/kg/day (50 mg/kg/day in 3 doses) for common pediatric infections.
Fuel Consumption (km/L)
Calculates average km/L from distance driven and liters refueled.
Fuel Cost per 100 km
Calculates fuel cost per 100 km given the vehicle consumption in km/L and price per liter.
Travel Time (mph and km/h)
Calculates travel time from distance and average speed, accepting mph or km/h input.
Cycling Travel Time
Estimates cycling time for a distance using typical speeds (touring 15 km/h, urban 20 km/h).
Walking Travel Time
Estimates walking time (slow 4 km/h, normal 5 km/h, brisk 6 km/h) for a distance in km.
Tire Pressure kPa to psi
Converts tire pressure between kPa, bar and psi, showing impact on fuel efficiency.
Wheel RPM from Speed
Calculates wheel rotation in RPM from tire diameter and vehicle speed in km/h.
Vehicle Braking Distance
Calculates braking distance d=v²/(2·µ·g) in meters from speed and friction coefficient.
Egg Boil Time by Altitude
Computes extra time to boil eggs at high altitude where water boils below 100C.
Baking Powder to Baking Soda
Converts baking powder grams into baking soda plus acid (lemon juice or vinegar).
Cup to Grams Converter
Converts cups of common ingredients (flour, sugar, milk, butter) to grams.
Spoon to Grams (Fats)
Converts table and tea spoons of oil, butter and margarine to grams and milliliters.
Milk to Plant Milk Substitution
Provides plant milk substitution amounts (almond, oat, coconut, soy) for cow milk in recipes.
White Sugar to Brown Sugar
Converts white sugar to brown or demerara in recipes adjusting batter moisture.
Coffee Amount per Person
Computes coffee grounds and water for traditional brewing for N people.