Calculators
Free online calculators for everyday calculations.
Financial
Mortgage Calculator
Calculate monthly payments, total interest, and view amortization schedule.
Open Calculator →Tip Calculator
Calculate tip amount and split the bill between multiple people.
Open Calculator →Compound Interest Calculator
Calculate how your investment grows over time with compound interest and optional regular contributions.
Open Calculator →Loan Calculator
Calculate monthly payments, total interest, and total cost on personal loans.
Open Calculator →Sales Tax Calculator
Calculate sales tax amount and total price for any US state or custom rate.
Open Calculator →Discount Calculator
Calculate discount amounts and final prices with percentage or dollar-off discounts.
Open Calculator →Salary Calculator
Convert between annual, monthly, biweekly, weekly, and hourly pay rates.
Open Calculator →Electrical
Electricity Cost Calculator
Estimate the cost of running appliances based on wattage, usage hours, and electricity rate.
Open Calculator →Ohm's Law Calculator
Calculate voltage, current, resistance, or power from any two known values using Ohm's Law and power formulas.
Open Calculator →Power Calculator
Calculate electrical power. Convert watts to amps, amps to watts, and volts to watts for DC, single-phase, and three-phase AC circuits.
Open Calculator →Wire Size Calculator
Find the minimum wire gauge (AWG) for a given load based on NEC 310.16 ampacity tables and voltage drop limits.
Open Calculator →Voltage Drop Calculator
Calculate voltage drop over a wire run for single-phase or three-phase circuits, based on wire gauge, distance, and current.
Open Calculator →Resistor Color Code Calculator
Decode resistor values from 4, 5, or 6 color bands, or find the color code for any resistance value and tolerance.
Open Calculator →Voltage Divider Calculator
Solve for output voltage or either resistor in a two-resistor divider, with optional load to show the real-world loading effect.
Open Calculator →LED Resistor Calculator
Calculate the current-limiting resistor for an LED or LED chain from supply voltage, forward voltage, and forward current.
Open Calculator →Battery Life Calculator
Estimate how long a battery lasts from its capacity, the load it drives, efficiency, and an optional Peukert correction.
Open Calculator →555 Timer Calculator
Calculate frequency, period, duty cycle, and pulse width for the 555 timer IC in astable (oscillator) or monostable (one-shot) mode.
Open Calculator →Resistor Network Calculator
Combine up to 10 resistors in series or parallel. Live SVG schematic, total resistance, conductance, and optional current and power from an applied voltage.
Open Calculator →RC Filter Calculator
Design a first-order RC low-pass or high-pass filter. Solve for cutoff frequency, capacitance, or resistance, and read attenuation and phase at any probe frequency.
Open Calculator →Power Factor Calculator
Calculate AC power factor, phase angle, apparent power, and reactive power. Size correction capacitors to improve PF for single-phase or three-phase systems.
Open Calculator →Inductance Calculator
Combine inductors in series or parallel, and calculate stored energy, inductive reactance, and RL time constant. Live SVG schematic, smart unit formatting.
Open Calculator →Capacitance Calculator
Combine capacitors in series or parallel, and calculate stored charge Q = CV, energy E = ½CV², and the RC time constant. Live SVG schematic, smart unit formatting.
Open Calculator →Health
BMI Calculator
Calculate your Body Mass Index and see your weight category.
Open Calculator →Calorie Calculator
Calorie and TDEE calculator. Find your Total Daily Energy Expenditure and BMR with Mifflin-St Jeor and Harris-Benedict equations, plus macronutrient breakdown for your caloric goals.
Open Calculator →Pace Calculator
Calculate running pace, time, or distance. Enter any two values to find the third, with split times for your run.
Open Calculator →Pregnancy Calculator
Pregnancy and due date calculator. Estimate your due date from last menstrual period or conception date, with week-by-week pregnancy timeline.
Open Calculator →Math
Percentage Calculator
Calculate percentages, percentage change, and more.
Open Calculator →Fraction Calculator
Add, subtract, multiply, and divide fractions with step-by-step working shown.
Open Calculator →Square Footage Calculator
Calculate the area of rooms and spaces from dimensions. Supports multiple shapes and multi-room totals.
Open Calculator →Date & Time
Cooking
Marketing
ROAS Calculator
Calculate Return on Ad Spend (ROAS) from revenue and ad spend, or solve for the missing input. Shows ratio, percentage, and break-even status.
Open Calculator →CPC Calculator
Calculate Cost Per Click (CPC) from total cost and clicks, or solve for the missing input. The IAB standard pricing metric for paid search and performance advertising.
Open Calculator →CPM Calculator
Calculate Cost Per Mille (CPM) from total cost and impressions, or solve for the missing input. The IAB standard pricing metric for impression-based advertising.
Open Calculator →Business
Markup Calculator
Calculate markup percentage, selling price, or cost. Includes margin-to-markup converter and shows gross margin, profit, and price multiplier.
Open Calculator →Break-Even Calculator
Calculate the break-even point in units, fixed costs, selling price, or variable cost per unit. Shows contribution margin and break-even revenue.
Open Calculator →Profit Margin Calculator
Calculate gross, operating, and net profit margins from revenue and costs. Solve for revenue or COGS at a target margin.
Open Calculator →