What is it?
The Ratio Calculator finds the missing number in a ratio such as 2 : 3 = 10 : ?. It also shows the ratio in its simplest form, as 1 : n, and as a share of the total.
Who is it for?
Students, cooks scaling recipes, farmers mixing fertilisers, builders mixing concrete, and partners sharing profits.
How to use it
Enter A, B and C. The answer appears as you type; there is no Calculate button. Tap Copy result to copy it, or Share on WhatsApp to send it.
Everyday uses
- Recipes: 2 cups rice : 3 cups water = 5 cups rice : ? (7.5 cups water). The Recipe Scaler does whole recipes.
- Mixing: concrete 1 : 2 : 4, fertiliser or pesticide dilution like 1 : 50 (20 ml in a litre).
- Photos and screens: 1920 : 1080 simplifies to 16 : 9; a 1280-wide image keeps the shape at 720 high.
- Maps and models: use the Map & Model Scale Converter.
Sharing in a ratio
To share ₹90,000 between partners in the ratio 2 : 3 : 4: add the parts (9), divide (₹10,000 per part), and multiply: ₹20,000, ₹30,000 and ₹40,000.
Worked example
3 : 5 = 12 : ? gives 20; 48 : 60 simplifies to 4 : 5.
Errors and how to fix them
- “A cannot be 0”: a ratio can’t start from zero.
Open the tool: Ratio Calculator
Still stuck?
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Questions, or an error not listed here?
Tell us in the comments: what you were doing, the exact message you saw, and your device and browser. We read every comment and add new fixes to this article.