Ratio & Proportion
Ratio Calculator
Simplify a ratio, scale it, or divide a total amount in a given ratio such as 2:3:5 — with each share shown.
Share = Total × (part ÷ sum of parts)
Also called ratio solver · divide in ratio
Math · 10 calculators
Ratio & Proportion Calculators
Simplify ratios, solve proportions, find equivalent ratios, aspect ratios, scale ratios and the golden ratio.
Ratio & Proportion
Ratio Simplifier
Simplify any ratio (including decimals and three or more parts) to its lowest whole-number terms.
Divide every term by their greatest commo…
Also called simplify ratio · reduce ratio
Ratio & Proportion
Proportion Calculator
Solve proportions A/B = C/D for the missing value using cross-multiplication, with steps.
A/B = C/D ⇒ D = B × C ÷ A
Also called cross multiplication calculator · solve for x proportion
Ratio & Proportion
Equivalent Ratio Calculator
Generate a table of equivalent ratios or scale a ratio so one term matches a target value.
a : b = ka : kb
Also called equivalent ratios · scale a ratio
Ratio & Proportion
Ratio to Percentage Calculator
Convert a ratio such as 3:2 or 1:4:5 into the percentage share of each part.
Part % = part ÷ sum of parts × 100
Also called ratio to percent · convert ratio to percentage
Ratio & Proportion
Percentage to Ratio Calculator
Turn a percentage into a simplified ratio, e.g. 40% → 2:3 (part to rest) or 2:5 (part to whole).
p% → p : (100 − p)
Also called percent to ratio · convert percentage to ratio
Ratio & Proportion
Golden Ratio Calculator
Find golden-ratio proportions (φ ≈ 1.618): split a length into long and short sections or extend it — used in design and layout.
φ = (1 + √5)/2 ≈ 1.6180339887
Also called phi calculator · golden section
Ratio & Proportion
Scale Ratio Calculator
Convert between real and scaled sizes using a scale ratio like 1:50 or 1:24, or find the scale from two lengths.
Scaled = Real ÷ k (for a 1:k scale)
Also called scale factor ratio · scale conversion
Ratio & Proportion
Aspect Ratio Calculator
Find the aspect ratio of any width × height, or calculate a missing dimension for 16:9, 4:3, 21:9 and custom ratios.
W : H = (W ÷ GCD) : (H ÷ GCD)
Also called aspect ratio · 16:9 calculator
Ratio & Proportion
Part-to-Part Ratio Calculator
Convert between part-to-part and part-to-whole ratios and find each part from a total.
A : B → A : (A + B)
Also called part to whole ratio · part to part
Key ratio & proportion formulas
| Ratio | Share = Total × (part ÷ sum of parts) |
|---|---|
| Ratio Simplifier | Divide every term by their greatest common divisor |
| Proportion | A/B = C/D ⇒ D = B × C ÷ A |
| Equivalent Ratio | a : b = ka : kb |
| Ratio to Percentage | Part % = part ÷ sum of parts × 100 |
| Percentage to Ratio | p% → p : (100 − p) |
| Golden Ratio | φ = (1 + √5)/2 ≈ 1.6180339887 · a/b = (a+b)/a = φ |
| Scale Ratio | Scaled = Real ÷ k (for a 1:k scale) |
| Aspect Ratio | W : H = (W ÷ GCD) : (H ÷ GCD) · H = W × b ÷ a |
| Part-to-Part Ratio | A : B → A : (A + B) |
Ratio & Proportion questions
What is the rule of three?
If A corresponds to B, then C corresponds to B × C ÷ A. It is the everyday name for solving a direct proportion, e.g. 3 apples cost $4, so 9 apples cost $12.
What are the common aspect ratios?
16:9 for HD video and most monitors, 4:3 for older TVs and iPads, 21:9 for ultrawide displays, 1:1 for square social posts, 9:16 for vertical video and 3:2 for many camera sensors.