TechCalc Pro

Rang Do

About this app

TechCalc Pro is a professional-grade offline toolkit built for scientists, engineers, technicians, and students. It combines a Chemical Solution Calculator, Electrical Engineering Calculator, and a full Notepad — all in one app that works entirely without internet access.


CHEMICAL CALCULATOR

Molarity (C = n / V)
Solve for concentration, moles, or volume — enter any two values and calculate the third instantly.

Dilution (C₁V₁ = C₂V₂)
Calculate any of the four dilution variables: initial concentration, initial volume, final concentration, or final volume.

pH / pOH
Enter a pH value and instantly get [H⁺], [OH⁻], and pOH — or work backwards from [H⁺] concentration. Calculated at 25 °C using Kw = 1 × 10⁻¹⁴.

Mass & Moles (n = m / MW)
Solve for moles, mass in grams, or molar mass — essential for stoichiometry and lab preparation.


ELECTRICAL CALCULATOR

Ohm's Law (V = IR)
Solve for voltage, current, or resistance — the foundational tool for every circuit calculation.

Power Calculator
Supports three formulas: P = V × I, P = I² × R, and P = V² / R. Select your formula, choose what to solve for, and calculate instantly.

Series Resistors
Add as many resistors as you need. The app calculates the total resistance in real time using Rₜ = R₁ + R₂ + R₃ + …

Parallel Resistors
Add resistors and instantly see the combined resistance using 1/Rₜ = 1/R₁ + 1/R₂ + … Results are displayed in Ω, kΩ, MΩ, or GΩ automatically.

Resistor Colour Code Decoder
Select the four colour bands of any resistor and read the resistance value and tolerance instantly. Includes a visual colour-band display for easy identification.


NOTEPAD

A distraction-free professional notepad for lab notes, field observations, calculations, and technical references. Notes are saved locally on your device — nothing leaves your phone.

• Create, edit, and organise unlimited notes
• Notes auto-sort by last modified date
• Unsaved-changes warning protects your work
• Swipe or long-press to delete, with one-tap undo


WHY TECHCALC PRO

✔ Fully offline — works in the lab, field, or anywhere without signal
✔ Zero permissions — no camera, no location, no storage access required
✔ No ads, no subscriptions, no account needed
✔ Supports scientific notation for very large and very small values
✔ Built by a professional scientific and technical services organisation