Calculators that show their work.
27 hand-built calculators across Finance, Utilities, Maths, Physics and Chemistry — each one explains the formula and walks through every step.
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Simple inputs — no jargon, no unnecessary fields.
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Step-by-step solution updates instantly as you type.
Understand the concept
Every page explains the formula and the maths behind it.
Finance
Loans, investments, GST and savings — with step-by-step breakdowns.
EMI Calculator
Monthly installment for home, car or personal loans.
EMI = P·R·(1+R)ᴺ ÷ [(1+R)ᴺ − 1]
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SIP Calculator
Future value of a monthly mutual-fund SIP.
FV = P · [(1+i)ⁿ − 1] ÷ i · (1+i)
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Compound Interest
Growth of an investment with compounding.
A = P · (1 + r÷n)ⁿᵗ
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GST Calculator
Add GST to a base price or extract it from gross.
Price incl. GST = Original × (1 + Rate÷100)
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FD Calculator
Maturity value and interest for any FD with quarterly, monthly or annual compounding.
A = P · (1 + r÷n)ⁿᵗ | EAR = (1 + r÷n)ⁿ − 1
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PPF Calculator
15-year PPF corpus with year-by-year interest table at the current 7.1% rate.
Balanceᵧ = Balanceᵧ₋₁ · (1 + r) + Deposit
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Gratuity Calculator
Gratuity payout for salaried employees under the Payment of Gratuity Act.
Gratuity = Salary × 15 × Years ÷ 26
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NPS Calculator
Retirement corpus and monthly pension with custom E / C / G asset allocation.
Corpus = P · [(1+i)ⁿ − 1] ÷ i · (1+i)
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Loan Prepayment
See exactly how much a lump-sum prepayment saves, and what investing the freed EMI could grow to.
Balance = P·(1+R)ᵏ − EMI·[(1+R)ᵏ − 1] ÷ R
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Utilities
Quick utilities you reach for every other day.
Percentage Calculator
Find any percentage — of a number, change, or difference between two values.
% Change = (New − Old) ÷ Old × 100
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BMI Calculator
Body Mass Index and WHO health category.
BMI = Weight (kg) ÷ Height (m)²
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Age Calculator
Exact age in years, months & days.
Age = Reference Date − Date of Birth
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Unit Converter
Convert between common SI and imperial units.
Result = Value × toBase × fromBase
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Maths
Algebra, combinatorics, probability & statistics — with worked solutions.
Quadratic Equation
Roots, discriminant & vertex of any quadratic.
x = (−b ± √(b²−4ac)) ÷ 2a
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Permutation & Combination
nPr, nCr and a step-by-step factorial breakdown.
ⁿPᵣ = n! ÷ (n−r)! · ⁿCᵣ = n! ÷ r!(n−r)!
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Mean, Median, Mode
Descriptive statistics for any data set.
x̄ = Σxᵢ ÷ n · σ = √(Σ(xᵢ−x̄)² ÷ n)
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Birthday Problem
Probability that two people in a group share a birthday.
P(match) = 1 − 365! ÷ ((365−n)! · 365ⁿ)
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Physics
Mechanics, electricity & motion — the core JEE/NEET physics toolkit.
Force (F = ma)
Newton's second law — solve for F, m or a.
F = m × a
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Kinetic Energy
Translational kinetic energy of a moving body.
KE = ½ · m · v²
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Ohm's Law
Voltage, current & resistance — solve for any one.
V = I × R · P = V × I
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Projectile Motion
Range, max height and time of flight from u and θ.
R = u²·sin2θ ÷ g · H = u²·sin²θ ÷ 2g
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Escape Velocity
Minimum speed to escape a planet's gravity.
vₑ = √(2GM ÷ R)
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Chemistry
Stoichiometry, solutions & gas laws — bread-and-butter board & entrance topics.
Molar Mass
Sum atomic masses of every element in a formula.
M = Σ (Atomic Mass × Subscript Count)
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pH Calculator
pH from [H⁺], pOH from [OH⁻] and vice versa.
pH = −log₁₀[H⁺] · pH + pOH = 14
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Ideal Gas Law
Solve for any unknown in PV = nRT.
PV = nRT
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Molarity
Concentration of a solution in mol/L.
M = moles ÷ Volume (L)
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Empirical Formula
Simplest whole-number ratio from % composition.
Ratio = Moles ÷ Smallest mole value
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