Proportion Calculator: Fast and Simple

Use this proportion calculator to solve a over b equals c over d. Enter three values to find the fourth. Or fill all four to test if the ratios match. The fields are labeled a, b, c, and d for clarity. Use Clear All to reset everything fast.

What It Does

The proportion calculator works with the rule a over b equals c over d. It solves a missing value with cross multiplication. It also checks if two ratios are equal.

• If a is missing, a equals b × c ÷ d.
• If b is missing, b equals a × d ÷ c.
• If c is missing, c equals a × d ÷ b.
• If d is missing, d equals b × c ÷ a.

When you solve, the tool fills the blank field. It shows the formula used. When you check, it compares a over b and c over d. It tells you if both ratios match. You will see both ratio values in the result.

The check allows a small rounding gap for decimals. Results show up to six decimal places when needed.

How to Use It

Step-by-Step Process

1. Decide your goal. Solve a missing value or check a proportion.
2. Enter numbers in a, b, c, and d as needed.
3. For solving, fill any three fields.
4. For checking, fill all four fields.
5. Select Calculate to get your result.
6. Select Clear All to reset inputs and output.

What each input means and what to enter:

• a: first value in the left ratio. Use any number.
• b: second value in the left ratio. Use a value other than 0 for checks.
• c: first value in the right ratio. Use any number.
• d: second value in the right ratio. Use a value other than 0 for checks.

How to read the output:

• Solving mode shows Solution found and the computed value.
• The formula used appears under the answer.
• Check mode shows if the proportion is valid or not valid.
• You also see each ratio value for clarity.

Limits and special notes:

• Use numbers only, integers or decimals.
• For solving a, set d to any number other than 0.
• For solving b, set c to any number other than 0.
• For solving c, set b to any number other than 0.
• For solving d, set a to any number other than 0.
• For checks, set b and d to values other than 0.
• Stick with the same units on both sides for clean results.

Why Use This Proportion Calculator

This proportion calculator is quick and clear. It explains each step with the formula used. It supports decimals and rounds to six places. It flags divide by zero before any math. The labels a, b, c, and d keep data entry simple. The Clear All button gives you a fresh start in one click. It offers a unique mix of speed and transparency.

Common use cases:

• Find a missing value in a ratio problem.
• Scale a recipe with ingredient ratios.
• Work with map scales or model scales.
• Convert rates like miles per hour and kilometers per hour.
• Mix solutions with fixed parts or ratios.
• Check a percent setup like part over whole equals percent over 100.

A Few Quick Tips

• Enter three values to solve the fourth value.
• Enter all four values to check the proportion.
• Use any number except 0 for b and d during checks.
• Keep units consistent across both ratios.
• Expect rounding to six decimal places on decimal answers.
• Example solve: 2 over 5 equals c over 20, c equals 8.
• Example check: 3 over 4 and 6 over 8 match.
• Need a clean slate, select Clear All.

Final Thoughts

This proportion calculator solves or checks ratios with clear math. You get the answer and the method in seconds. No fluff, just results you can trust.

Enter your numbers, select Calculate, and move on. Simple, fast, and accurate for daily work or study.