Ratio Calculator
Simplifies a:b with GCD for positive integers, or normalizes non-integers to 1:x. Split-total mode allocates a positive total across the ratio parts.
Limitation: Two-part ratios only.
How to Work With Ratios
Enter both parts. Use simplify to reduce the ratio, or split-total to allocate a positive total across those parts.
Choose simplify or split total.
Proportions next door
If you need to solve a/b = c/d for a missing term, open the Proportion Calculator.
Simplify and Share
Integer pairs divide by their GCD. Non-integer pairs normalize so the first part becomes 1. Split mode uses part/(a+b) of the total.
Worked Ratio Examples
Simplify 8:12
Inputs
Result
gcd(8,12)=4; 8/4:12/4 = 2:3.
Split 100 in 2:3
Inputs
Result
2/5 of 100 is 40; 3/5 is 60.
Decimal ratio 2.5:5
Inputs
Result
Normalize by dividing both parts by 2.5.
Fractions link
2:3 as a fraction of the whole is 2/5 and 3/5—try the fraction calculator for further arithmetic.
Frequently Asked Questions
Still have questions about this calculation?
Try the CalculatorRatio Formulas
Simplification and proportional shares share the same part weights.
Formula
Integer simplify
a:b → (a/g):(b/g) where g = gcd(a,b)
Split total
shareA = total × a ÷ (a + b)
Scientific Background
A ratio compares relative size. It is not yet a solved proportion until you equate two ratios—that is the next tool.
Sources & review
Ratio Calculator documents the references behind its formulas and assumptions. Always treat results as educational estimates, not personalized professional advice.
Last reviewed
July 22, 2026
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