Inductor Calculator Master vs GraphCalc

Inductor Calculator Master is the most complete offline coil calculator for electronics engineers, RF hobbyists, audio builders, and students who work with inductors every day. No internet. No accounts. No guesswork. Enter your coil dimensions and get accurate results instantly — whether you are in the workshop, in the field, or somewhere with no signal at all. WHAT YOU CAN CALCULATE 1. Air Core Solenoid Calculate inductance, wire length, and DC resistance for single-layer air-core coils. Supports both mm and inch units. Includes a coil diagram and practical winding tips from the electronics community. 2. Multi-Layer Coil Handle multi-layer windings using the correct multi-layer Wheeler formula. The app automatically warns you when your geometry would make a single-layer formula unreliable. 3. Toroid — Two Methods AL Value Method: enter the core's AL value and number of turns to get inductance. Physical Dimensions Method: enter outer diameter, inner diameter, height, and relative permeability to get inductance. Both methods output wire length and DC resistance. 4. LC Resonant Circuit Enter inductance and capacitance to get resonant frequency. Or enter target frequency and capacitance to find the required inductance. Instantly check whether your LC tank circuit hits the right frequency. BUILT FOR REAL WORKFLOWS 1. Target Solver Know your target inductance? Enter it along with your coil geometry and the app tells you exactly how many turns to wind — no trial-and-error, no spreadsheets. Supports Air Core, Multi-Layer, Toroid AL, and Toroid Physical modes. 2. Correct My Coil Wound a coil that measures the wrong value on your LCR meter? Enter your measured inductance, your target inductance, and the current number of turns. The app calculates precisely how many whole turns to add or remove. 3. Compare 2 Designs Enter two Air Core configurations side by side and compare their inductance, wire length, and DC resistance in a single view. Faster than switching between tabs and recalculating manually. 4. Save to History Every calculation can be saved and recalled later. All inputs and outputs are preserved exactly as you entered them — no re-entering values across sessions. EVERY RESULT INCLUDES - Inductance displayed in auto-scaled units (H, mH, µH, or nH) - Wire length required for the complete winding - DC winding resistance - Confidence rating (High, Medium, or Low) based on how well your geometry fits the formula's valid range - Geometry-specific warnings when inputs fall outside ideal formula boundaries - Real-world winding tips drawn from electronics community experience 100% OFFLINE All calculations run entirely on your device. No data is ever sent to a server. The app works anywhere — workshop bench, shack, stockroom, or a metal building that kills your signal. PRICING - Free: All four main calculators (Air Core, Multi-Layer, Toroid, LC Resonant). Unlimited calculations, no time limits. - Remove Ads — $0.99: Removes the banner ad from every screen. One-time purchase, no subscription. - Premium — $1.99: Unlocks Quick Tools — Target Solver, Correct My Coil, and Compare 2 Designs. One-time purchase. Restore Purchases is fully supported. WHO IT IS FOR Amateur radio operators building tank circuits, filters, and matching networks. Audio engineers designing speaker crossover inductors. Power supply designers specifying filter chokes. Students studying electromagnetic induction and RF theory. Makers and hobbyists winding anything from custom sensors to coilgun stages. If you wind wire around a form, this app belongs on your phone.

GraphCalc is a complete math toolkit for students, teachers, and anyone who needs to calculate, graph, or solve — all in one app, all on your device. CALCULATOR (Free) A full scientific calculator with trigonometric, logarithmic, exponential, and root functions, plus a live preview of your result as you type. GRAPHER (Free) Plot any function and explore it with pinch-to-zoom and pan. Add a slider for any parameter (like the “a” in a·sin(x)) and watch the curve move as you drag it. See exactly where two curves cross, find roots and extrema automatically, and share a clean image of your graph. UNIT CONVERTER (Free) Convert length, mass, temperature, area, volume, speed, time, pressure, energy, power, and digital storage — all offline. EQUATIONS Solve systems of linear equations (2 to 5 variables) and quadratic equations, step by step. MATRICES Compute determinants, inverses, and transposes, or add, subtract, and multiply matrices up to 4×4. CALCULUS See the full worked solution, not just the answer: • Derivatives — every rule applied, one step at a time (product, quotient, chain, power) • Limits — direct substitution, with L'Hôpital's rule applied automatically when needed • Integrals — numeric area under any curve Equations, Matrices, and Calculus (with full step-by-step work) unlock together with a single one-time purchase of $4.99 — no subscription, no recurring charges, yours forever. GraphCalc works completely offline: nothing is ever collected, uploaded, or shared. Available in English and Spanish, matching your device's language automatically.