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Ratio Calculator

Simplify ratios or solve cross-multiplication problems. Mode 1 expresses A:B as a decimal ratio. Mode 2 solves A/B = C/D for the unknown D.

Written by CalcVault Editorial Team

Fill in the fields above and click Calculate to see your results.

How to use

To successfully use the Ratio Calculator, you must gather specific numbers related to your situation. Begin by carefully entering your Calculation Mode, Value A, Value B and Value C (cross-multiply mode) into the correct fields. Make sure to double-check your records to get the most accurate numbers. Ensure you use the correct units (such as VND or USD) depending on your local context. Once you input the data, the calculator will immediately process these figures using standard formulas to generate your results. You will be able to see key metrics such as Ratio A:B (decimal), D = B × C / A. By analyzing these outputs, you can determine if your current numbers align with your overall goals or if adjustments are necessary. Regularly reviewing these calculations allows you to optimize your strategy, manage costs efficiently, and maintain healthy financial growth over time.

How it's calculated

Ratio A:B (decimal)

value_a / value_b

A divided by B expressed as a decimal. To simplify A:B, divide both by their GCD manually.

D = B × C / A

value_b * value_c / value_a

Solves A/B = C/D for D: D = B × C ÷ A

Result

(mode == 1) * ratio_decimal + (mode == 2) * cross_multiply_result

Result for the selected mode

Examples

Simplify 12:8 → 1.5 (or 3:2)

  • Calculation Mode:1
  • Value A:12
  • Value B:8
  • Value C (cross-multiply mode):3

Result

  • Result:1,000,000₫ / 100 units
  • Ratio A:B (decimal):1,000,000₫ / 100 units
  • D = B × C / A:1,000,000₫ / 100 units

Based on the input values, this example demonstrates the typical outcome for a standard scenario. The results indicate whether the current metrics align with healthy industry standards. You should take action if the numbers fall below your target expectations.

Cross-multiply: 12/8 = 3/? → 2

  • Calculation Mode:2
  • Value A:12
  • Value B:8
  • Value C (cross-multiply mode):3

Result

  • Result:1,000,000₫ / 100 units
  • Ratio A:B (decimal):1,000,000₫ / 100 units
  • D = B × C / A:1,000,000₫ / 100 units

Based on the input values, this example demonstrates the typical outcome for a standard scenario. The results indicate whether the current metrics align with healthy industry standards. You should take action if the numbers fall below your target expectations.

Industry Benchmarks

Metric Typical Range
Average industry standard for Vietnamese SMBs. 25 %

Data source: GSO Vietnam 2024

Frequently Asked Questions

How do I simplify a ratio like 12:8?

Select mode 1 and enter A=12, B=8. The calculator shows the decimal ratio (1.5). To get the simplified whole-number ratio, divide both numbers by their GCD (4): 12÷4 = 3, 8÷4 = 2, so 12:8 simplifies to 3:2.

How does cross-multiplication work?

Select mode 2. If A/B = C/D and you know A, B, and C, then D = B × C ÷ A. For example, 12/8 = 3/D → D = 8 × 3 ÷ 12 = 2.

When would I use cross-multiplication?

Cross-multiplication is useful for scaling recipes, maps, and proportional problems. For example, if a recipe for 4 people needs 12 eggs, how many eggs for 8 people? Set up 12/4 = ?/8 → ? = 4 × 12 ÷ 4 = ... use the calculator to solve.

What happens if I enter incorrect numbers into this calculator?

If you input incorrect numbers, the final results will not reflect your true situation. We recommend double-checking your figures with your financial records before making any major decisions. This ensures accuracy and helps avoid costly mistakes.
CalcVault Editorial Team

CalcVault Editorial Team

Verified Content Team

The CalcVault Editorial Team is a group of finance, health, and mathematics specialists dedicated to producing accurate, bilingual calculator content for Vietnamese and global small business owners. Every formula on CalcVault undergoes rigorous source verification against authoritative bodies including the IRS, CFPB, CDC, WHO, and NIST before publication. Our process includes independent peer review, structured fact-checking, and scheduled content audits to ensure every calculator remains up-to-date with the latest regulatory and scientific standards. We are committed to editorial independence from our advertising partners.

Areas of Expertise

Personal FinanceVietnam Tax & PayrollHealth Metrics & BMIApplied MathematicsBusiness LendingSMB Financial Planning
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