What the Ratio Calculator does
This tool takes two numbers and turns them into a clean, simplified ratio, along with its decimal value. Give it 16 and 9 and it confirms 16:9; give it 1920 and 1080 and it reduces that to 16:9 too. It helps designers checking aspect ratios, cooks scaling a recipe, students working through proportion problems, and anyone who needs to compare two quantities fairly. Because it also scales a ratio to a new size, it doubles as a quick proportion solver.
How to use it
- In the Term A field, enter the first number of your ratio.
- In the Term B field, enter the second number.
- (Optional) Type a target into Scale A to value if you want to resize the ratio to a new Term A.
- Press Calculate.
- Read the results: the simplified ratio, the decimal value of A divided by B, and the proportional B that matches your scaled A.
Worked example
Say you have a photo that is 1920 by 1080 and you want it 1280 wide. Put 1920 in Term A, 1080 in Term B, and 1280 in Scale A to value. The tool simplifies the ratio to 16:9, shows the decimal as about 1.778, and tells you the proportional B is 720, so your resized image stays 1280 by 720 without distortion.
Everything runs right in your browser, which keeps your numbers private. It is free, needs no sign-up, and works the same on a phone or a laptop.
Frequently asked questions
- How do I simplify a ratio?
- Enter your two numbers in Term A and Term B, then press Calculate. The tool divides both by their greatest common divisor and shows the reduced form, so 16 and 9 stays 16:9 while 1920 and 1080 also becomes 16:9.
- What does the Scale A to value field do?
- It keeps the ratio fixed while resizing it. Type a new value for Term A and the tool returns the matching Term B, so a 16:9 ratio scaled to a Term A of 1280 gives a B of 720.
- Is the Ratio Calculator free and private?
- Yes. It is completely free with no sign-up, and every calculation runs in your browser, so the numbers you enter are never uploaded anywhere.
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Last updated: June 17, 2026