EverydayElectricalPhysicsEngineeringFinanceConvertersStatistics

Calculators that just work.

68 tools. No signup. Instant answers.

Everyday

7

Percentage Calculator

Any percentage operation, instantly

BMI Calculator

Body mass index & weight category

Age Calculator

Exact age from birth date

Calorie Calculator (TDEE)

Daily energy expenditure estimate

Tip & Split

Bill split with tip per person

GPA Calculator

Weighted GPA on a 4.0 scale

Fuel Cost

Trip fuel expense estimate

Electrical

14

Ohm's Law

V, I, R, P from any two values

Voltage Divider

Output voltage, two-resistor

Wire Resistance

From wire gauge, length, material

RC Time Constant

τ and voltage response curves

LED Resistor

Safe current-limiting resistor

Voltage Drop

Loss from length & conductor

Capacitor Energy

Stored energy, charge, capacitance

Parallel Resistance

Equivalent of 2-4 resistors

Electrical Power

Power, energy, electricity cost

Filter Cutoff

-3dB point for LP/HP filters

Decibel (dB)

dB to linear ratio conversion

Power Factor

Power triangle, cosφ

Transformer

Turns ratio, output voltage

Inductor Energy

Energy in magnetic field

Physics

10

Reynolds Number

Laminar vs turbulent flow

Coulomb's Law

Force between point charges

Kinetic Energy

Energy, velocity, or mass

Pendulum Period

Period from pendulum length

Ideal Gas Law

Solve PV = nRT for any variable

Projectile Motion

Trajectory from angle & velocity

Snell's Law

Refraction angle between media

Wave Speed

Speed, frequency, wavelength

Gravitational Force

Attraction between two masses

Thermal Expansion

Material size vs temperature

Engineering

16

Pressure Drop

Darcy-Weisbach pipe loss

Stress & Strain

σ, ε, Young's modulus

Torque

Force, distance, or torque

Spring (Hooke's)

F = kx spring properties

Heat Transfer

Q = mcΔT thermal energy

Flow Rate

From pipe dimensions & velocity

Gear Ratio

Speed & torque ratios

Thermal Resistance

Heat flow, temp difference

Beam Deflection

Point load or UDL deflection

Bolt Torque

Torque for target preload

Bernoulli Equation

Between two flow points

Friction Force

Static or kinetic friction

Moment of Inertia

Rotational inertia of shapes

Hydraulic Cylinder

Force, pressure, bore size

Heat Exchanger LMTD

Counter & parallel flow LMTD

Nusselt Number

Convective heat transfer h

Finance

5

Salary to Hourly

Annual to hourly or vice versa

VAT / Sales Tax

Add or remove VAT

Profit Margin

Gross, net margin, markup

ROI

Return on investment %

Take-Home Pay

Net from gross salary

Converters

6

Hex / RGB / HSL

Color format conversion

Aspect Ratio

Resize keeping proportions

DPI / PPI

Print & display resolution

Unix Timestamp

Epoch to date & back

Subnet / CIDR

Hosts, broadcast, mask

Unit Converter

Quick common unit conversions

Statistics

10

Sample Size

Responses for significance

Z-Score

Standard deviations from mean

Confidence Interval

Range for population mean

Percentage Change

Change between two values

Compound Interest

Growth with compounding

Standard Error

SE from SD and sample size

Effect Size (Cohen's d)

Standardized difference between groups

Probability

Odds & combinatorial values

Break-Even

Units to cover all costs

Logarithm

Base 10, natural, any base

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