Math & Trig
Calculate a ratio from two numbers: simplified whole-number (16:9) and N:1
Reduce positive integer dimensions to lowest ratio terms with GCD, or express a ratio with a nonzero denominator in N:1 form.
Simplify integer ratios with Greatest Common Divisor (GCD)
Screen resolutions like 1920 x 1080 share a greatest common divisor of 120. Dividing both numbers by GCD(1920, 1080) reduces them to lowest whole-number terms: 1920/120 = 16 and 1080/120 = 9 ("16:9").
When inputs are decimals or financial metrics (such as Debt-to-Equity or Students-per-Teacher), dividing Left / Right and appending ":1" formats a unit ratio ("1.78:1").
| WidthPx (A) | HeightPx (B) | GCD(A, B) | Simplified Ratio | Unit N:1 Ratio |
|---|---|---|---|---|
| 1920 | 1080 | 120 | 16:9 | 1.78:1 |
| 2560 | 1600 | 320 | 8:5 | 1.6:1 |
Simplified whole-number ratio formula
Guarding OR(A2=0, B2=0) avoids uninformative 1:0 labels or #DIV/0! in unit ratios when one dimension is zero.
=IF(OR(A2=0, B2=0), "Undefined", (A2 / GCD(A2, B2)) & ":" & (B2 / GCD(A2, B2)))Unit N:1 ratio formula
ROUND(A2 / B2, 2) & ":1" normalizes the second term to 1 ("1.78:1").
=ROUND(A2 / B2, 2) & ":1"Try the example
Use the original values or change them to test your understanding.