Ratio Calculator - Simplify Ratios & Solve Proportions

Simplify Ratio

Enter numbers to simplify the ratio to its lowest terms:

:
:
Original Ratio: 12:18
Simplified Ratio: 2:3
Greatest Common Factor: 6
Decimal Form: 0.667
Percentage: 66.67% : 33.33%

Equivalent Ratios:

2:3 = 4:6 = 6:9 = 8:12 = 10:15 = 12:18 = 14:21 = 16:24 = 18:27 = 20:30

Solve Proportion

Find the missing value in a proportion (a:b = c:x):

:
=
:
Proportion: 2:3 = 8:x
Solution: x = 12
Cross Product: 2 × 12 = 3 × 8 = 24
Verification: 2/3 = 8/12 = 0.667

Scale Factor Calculator

Calculate scale factors for enlarging or reducing:

Scale Factor: 3:1 (3× enlargement)
Ratio: 15:5 = 3:1
Scaled Dimension: 8 × 3 = 24
Percentage: 300% of original size

Generate Equivalent Ratios

Create a list of equivalent ratios:

:
Base Ratio: 3:4
Equivalent Ratios:
3:4 = 6:8 = 9:12 = 12:16 = 15:20 = 18:24 = 21:28 = 24:32 = 27:36 = 30:40

Common Ratio Applications

Golden Ratio

Ratio: 1:1.618 (φ)

Uses: Art, architecture, design

Example: 8:13, 13:21, 21:34

Screen Resolutions

16:9: 1920×1080, 3840×2160

4:3: 1024×768, 1600×1200

21:9: 2560×1080, 3440×1440

Cooking Ratios

Rice to Water: 1:2

Coffee: 1:15 to 1:17

Bread: 5:3 (flour to water)

Photography

Rule of Thirds: 1:1:1

Print Sizes: 3:2, 4:3, 5:4

Aspect Ratios: 1:1, 3:2, 16:9

Finance

Debt-to-Income: 1:3 (ideal)

Savings Rate: 1:5 (20%)

Emergency Fund: 3:1 to 6:1

Chemistry

Dilution: 1:10, 1:100

Solutions: Molar ratios

Reactions: Stoichiometric ratios

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Ratio Calculator — quick guide

1) Core idea

Ratios compare quantities (a:b). You can simplify, solve proportions a:b = c:x, compute scale factors, and generate equivalents.

2) How this tool works

3) Sanity checks

4) Shortcuts that help

5) Common pitfalls

6) Micro-examples

7) Mini-FAQ

8) Action tip

Write ratios with units (e.g., cm:cm) and keep term order consistent across equalities.