NeutronDB is a free online calculator platform covering finance, mathematics, health, science, engineering, and geometry. Every calculator runs entirely in your browser - no signup, no data sent to a server, no ads blocking the result. Answers are instant and each page shows the formula, defined variables, and at least two worked examples so you can verify the logic yourself.

Most-used calculators

The most frequently used tools on NeutronDB are the EMI Calculator (monthly loan installments and full amortization schedule), the BMI Calculator (Body Mass Index with WHO category and healthy weight range), the Percentage Calculator (three modes: find a percentage, find what percent one number is of another, and find the original value), and the Age Calculator (exact age in years, months, and days from any date of birth).

Finance & Investment

NeutronDB's finance section covers loans, investments, tax, savings, banking, and retirement planning. The EMI Calculator computes monthly installments using the standard reducing-balance formula and shows a month-by-month amortization table. Investment calculators include SIP (Systematic Investment Plan with wealth-gain breakdown), Compound Interest (annual, semi-annual, quarterly, monthly, or daily compounding), PPF (Public Provident Fund with current 7.1% rate), FD (Fixed Deposit), and RD (Recurring Deposit). Tax tools include the GST Calculator (add or remove GST at any slab) and the Income Tax Calculator (India FY2024-25, both old and new regimes). Long-term planning tools include the NPS Calculator and the Loan Comparison Calculator (side-by-side EMI and total-cost comparison for up to two loans).

Health & Fitness

The BMI Calculator on NeutronDB supports both metric (kg/cm) and imperial (lb/ft/in) inputs and classifies results against WHO thresholds: underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30). It also shows the healthy weight range for your height. The BMR Calculator uses the Mifflin-St Jeor equation - the most accurate validated formula for most adults - to find basal metabolic rate. The Calorie Deficit Calculator converts BMR and activity level into a TDEE and calculates the daily deficit needed to reach a target weight.

Math & Statistics

The math section covers basic arithmetic (percentage, ratio, fractions), scientific functions (quadratic equations with real and complex roots, logarithms, trigonometry), and statistics. The Descriptive Statistics Calculator computes 25+ statistics from a data set - mean, median, mode, standard deviation, variance, quartiles, IQR, skewness, kurtosis, and a full frequency table. The Percentage Calculator handles three common query types in one tool.

Science & Engineering

Science calculators cover kinematics (projectile motion, velocity, acceleration), energy (work, power, kinetic and potential energy), thermodynamics, and stoichiometry. Engineering tools follow published standards: mechanical spring calculators use SMI and IS 7906 standards for spring rate, Wahl stress correction factor, and Goodman fatigue-life analysis. Electrical calculators cover AWG wire gauge selection, voltage drop, transformer turns ratio, and solar panel output estimation. Civil tools solve simply-supported beam reactions, bending moments, and pipe pressure drop using the Darcy-Weisbach equation.

Privacy & accuracy

All NeutronDB calculators run entirely in the browser using JavaScript. No input values are transmitted to any server. Formulas are sourced from standard engineering, finance, and scientific references and are shown in full on each page. If you find an error in any formula or result, use the feedback button on the calculator page to report it.