Voltage Divider Calculator
Calculate divided output voltage and resistor ratios for analog circuits — electronics engineering tool.
Engineering & TechnicalCalculators & ConvertersFree · No sign-up
Free Engineering Calculator Tools Online 2026 — Electronics & Applied Math
This hub gathers the most useful free browser-based engineering and applied mathematics calculator tools for electronics engineers, students, and makers in 2026: circuit calculators, power tools, math converters, and physics helpers — no signup required.
Updated · Reviewed by The Free AI Tools Editorial Team — Electronics engineering and applied math tools review
Top free tools
Open any tool instantly — no account or download required.
Ohm’s Law & Power Triangle Calculator
Calculate voltage, current, resistance, power, and related electrical values with unit switching and visual formulas. It is ideal for students, technicians, and makers who need quick checks with clear explanations.
LED Series Resistor Calculator
Calculate a safe resistor value and power rating for single-LED circuits — beginner electronics tool.
Resistor Color Code Calculator
Decode resistor bands visually, calculate tolerance, and switch between 4-band, 5-band, and 6-band modes. It helps electronics learners and hobbyists avoid common reading mistakes.
Capacitor Charge/Discharge Calculator
Estimate RC time constants and charge thresholds for timing circuits — capacitor electronics calculator.
Power Supply Runtime Calculator
Estimate battery runtime from capacity (mAh) and expected load current — power electronics tool.
Fraction Simplifier
Reduce fractions to lowest terms and convert to decimals and percentages — math tool for students.
Scientific Notation Converter
Convert numbers between expanded form and scientific notation — essential math and physics study tool.
Unit Circle Visualizer
Explore angles, radians, coordinates, sine, cosine, and tangent with an interactive unit circle and labeled quadrants. It turns a memorization-heavy topic into a visual learning experience.
Speed Distance Time Calculator
Calculate speed, distance, or time from any two known values — physics and travel planning formula tool.
Unit Converter
Convert between common units for length, weight, speed, and temperature — instant multi-unit calculator.
Percentage Calculator
Solve common percentage calculations instantly — what is X% of Y, percentage change, and reverse percent.
About these tools
Electronics engineers, hardware makers, and engineering students regularly need quick circuit calculations during design, prototyping, and troubleshooting. The engineering calculators in this hub provide immediate, accurate results for the most common circuit design calculations.
The voltage divider is one of the most fundamental circuits in electronics, used everywhere from ADC input scaling to bias networks to sensor signal conditioning.
LED circuit design requires accurate series resistance calculation to prevent LED burnout from excessive current. Under-resisting an LED reduces its lifespan from years to minutes.
Capacitor charge and discharge behavior is important in timing circuits, power supply filtering, and energy storage applications. The capacitor calculator computes the time constant and voltage at any point in the charge/discharge curve.
All tools in this topic
All 23 free tools related to this topic, organised by category.
Engineering & Technical
Ohm’s Law & Power Triangle CalculatorCalculate voltage, current, resistance, power, and related electrical values with unit switching and visual formulas. It is ideal for students, technicians, and makers who need quick checks with clear explanations.Resistor Color Code CalculatorDecode resistor bands visually, calculate tolerance, and switch between 4-band, 5-band, and 6-band modes. It helps electronics learners and hobbyists avoid common reading mistakes.Solar GeneratorEstimate solar generator battery capacity, inverter wattage, daily watt-hours, backup days, and panel count for portable power setups.
Calculators & Converters
Age CalculatorCalculate exact age from a birth date with years, months, and days — find how many days until your birthday.BMI CalculatorCalculate body mass index from weight and height — includes BMI category classification and health guidance.Compound Interest CalculatorEstimate future value and earned interest with annual compound growth — investment and savings planning tool.Currency ConverterConvert currencies with live exchange rates plus offline fallback — support for 150+ world currencies.Date Difference CalculatorMeasure the exact duration between two dates and times — calculate days, weeks, months, and hours between dates.Discount CalculatorWork out discount savings and final price after percentage reductions — calculate sale prices instantly.Electricity Cost CalculatorEstimate monthly electricity cost from wattage, daily runtime, and energy price — reduce your power bill.Fuel Cost CalculatorEstimate fuel needed and trip cost from distance, efficiency, and fuel price — plan road trips easily.GPA CalculatorEstimate GPA from course grades and credit hours — supports 4.0 and weighted grading systems.Loan CalculatorEstimate monthly EMI payments, total interest cost, and full repayment schedule for any loan.Margin CalculatorEstimate gross margin percentage and net profit from selling price and cost — essential for pricing decisions.Markup CalculatorCalculate selling price and profit from cost and markup percentage — retail pricing made simple.Pace CalculatorCalculate running pace per kilometer and average speed from distance and total time — runner's must-have tool.Percentage CalculatorSolve common percentage calculations instantly — what is X% of Y, percentage change, and reverse percent.Percentage Change CalculatorMeasure percentage increase or decrease between two values — essential for financial and analytics reporting.Roman Numeral ConverterConvert numbers to Roman numerals and vice versa — supports I to MMMCMXCIX with instant conversion.Speed Distance Time CalculatorCalculate speed, distance, or time from any two known values — physics and travel planning formula tool.Time Zone ConverterConvert a date and time across major world time zones — plan meetings across countries instantly.Tip CalculatorCalculate tip amount, total bill, and per-person split in one step — the easiest restaurant tip calculator.Unit ConverterConvert between common units for length, weight, speed, and temperature — instant multi-unit calculator.
Free engineering calculator tools FAQs
Quick answers about the workflow, privacy, and where this tool fits in a broader job.
How does the voltage divider calculator work?
Enter the input voltage and the values of the two resistors in the voltage divider circuit. The calculator computes the output voltage across the lower resistor using the standard formula: Vout = Vin × (R2 / (R1 + R2)).
What does the LED series resistor calculator determine?
The LED resistor calculator determines the correct series resistance needed to limit current through an LED to its rated forward current.
How does the resistor color code calculator work?
Select the color bands on your resistor using the tool's color band selector. The calculator decodes the resistor value in ohms, the tolerance, and the temperature coefficient from the color sequence.
What does the Ohm's law power triangle calculator cover?
The Ohm's law power triangle calculator derives any electrical parameter — voltage, current, resistance, or power — from two known values using the relationships V=IR, P=VI, and P=I²R.
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221+ browser-based tools across 13 categories — all free, no sign-up.