All in One Calculator - Math

All in One Math Calculator

Six calculators in one app — no ads, works offline.

$1.99 on both stores — one purchase, no ads, no subscription.

Try all six on this page No sign-up Every step shown

Six calculators, one board

Quadratic Equation Solver

Solving ax2 + bx + c = 0

Roots x₁ = 5,   x₂ = −3 Discriminant 64 is positive — two distinct real roots, so the parabola crosses the x-axis twice.

Step by step

  1. Start from the quadratic formula
    x = −b ± b2 − 4ac2a
  2. Substitute a, b and c
    x = −(−2) ± (−2)2 − 4(1)(−15)2(1)
  3. Work out the discriminant, b² − 4ac
    Δ = (−2)2 − 4(1)(−15) = 64
  4. The discriminant is a perfect square, so the roots are rational
    64 = 8
  5. Take the plus branch
    x₁ = 2 + 82 = 5
  6. Take the minus branch
    x₂ = 2 − 82 = −3

Also worth knowing

Vertex
(1, −16)
Axis of symmetry
x = 1
Discriminant
64
Parabola opens
upward
Factored form
(x − 5)(x + 3) = 0

Fraction Calculator

Result 56 As a decimal: 0.833333.

Step by step

  1. The problem
    12+13
  2. Find the least common denominator of 2 and 3
    LCD = 6
  3. Rewrite both fractions over that denominator
    12 = 3613 = 26
  4. Add the numerators
    3 + 26 = 56
  5. The result is already in lowest terms
    gcd(5, 6) = 1

Sarrus Rule Calculator

↘ down-right diagonals are added ↗ up-right diagonals are subtracted

Determinant det A = 26 A non-zero determinant means the matrix is invertible and its rows are linearly independent.

Step by step

  1. Copy the first two columns to the right of the matrix
    22−5223153172.2672.2
  2. Multiply along the three diagonals going down-right, and add them
    2 × 1 × 6 + 2 × 5 × 7 + (−5) × 3 × 2.2
  3. That gives the positive part of the determinant
    12 + 70 + −33 = 49
  4. Multiply along the three diagonals going up-right, and add them
    7 × 1 × (−5) + 2.2 × 5 × 2 + 6 × 3 × 2
  5. That gives the part to be subtracted
    −35 + 22 + 36 = 23
  6. Subtract the second sum from the first
    det = 49 − 23 = 26

Base Converter

Binary base 2
11010110
Octal base 8
326
Decimal base 10
214
Hexadecimal base 16
D6
Base 10 214 11010110 in base 2 is 214 in decimal.

Step by step

  1. Give each digit its place value — powers of 2, right to left
    1×27 + 1×26 + 0×25 + 1×24 + 0×23 + 1×22 + 1×21 + 0×20
  2. Work out each term
    128 + 64 + 0 + 16 + 0 + 4 + 2 + 0
  3. Add them up
    110101102 = 21410

Area Calculator

w
Area 84 Perimeter 38 Rectangle: area 84, perimeter 38.

Step by step

  1. Multiply width by height
    A = w × h = 12 × 7 = 84
  2. Add both pairs of sides
    P = 2(w + h) = 2(12 + 7) = 38

Rule of Three Calculator

x
?
x x = 37.5 Direct proportion: C is 0.15× A, so x is the same multiple of B.

Step by step

  1. Set the two ratios equal to each other
    100250 = 15x
  2. Cross multiply
    100 × x = 250 × 15
  3. Divide both sides by A to isolate x
    x = 250 × 15100 = 3750100
  4. Work out the division
    x = 37.5

All six calculators in one app, offline and ad-free. $1.99, bought once.

What it does

All in One Calculator

Every calculator on this site, in one place. Switch between fractions, quadratic equations, 3×3 determinants, base conversion, area and the rule of three without leaving the page — and try each one before deciding whether the app is worth it.

Six tools, one app

Replaces six single-purpose calculators, and the ones added later are included.

No ads, ever

A one-time purchase rather than an ad-supported free app.

Works offline

Everything runs on-device, so it works in an exam hall or on a plane.

All future calculators

New calculators added to the app are included at no extra cost.

How it works

Three steps to an answer

  1. Pick a calculator

    Six tabs, one for each tool. Your last-used tool is remembered.

  2. Enter your values

    Each tool keeps the same clean layout, so there is nothing new to learn.

  3. See the steps

    Every tool shows its working, not just the final answer.

In the app

What All in One Calculator looks like on your phone

The same calculator, built for touch — plus the AI explanation and dark mode that come with PRO.

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FAQ

Questions people ask

What is included in All in One Calculator?

Six calculators in a single app: fractions, quadratic equations, 3×3 determinants by the rule of Sarrus, base conversion, area and perimeter, and the rule of three.

One app instead of six →
Is All in One Calculator free?

No — it is a paid app, bought once with no ads and no subscription. Every calculator it contains is also free to use on this website.

Does it work offline?

Yes. All the calculations run on your device, so the app works with no internet connection at all.

Why offline matters →
Will new calculators be added?

Yes, and they are included at no extra cost — the one purchase covers future calculators added to the app.

Should I get this or the individual apps?

If you need more than one or two of the calculators, All in One is the simpler choice and removes the ads. If you only ever need a single tool, the individual app for it is free to download.

How to choose →

Take All in One Calculator with you

Every calculator on this site, in one app that works offline with no ads and no subscription.

$1.99 on the App Store and Google Play. One purchase, no ads, no subscription.