Mixing Ratio Calculator
Calculate precise component amounts for any multi-part mixture. Enter a mixing ratio like 3:1, 4:1:1, or 1:2:3 with your total volume or weight to get exact measurements for each component — essential for paint mixing, epoxy casting, concrete batching, and chemical formulation.
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What is a Mixing Ratio?
A mixing ratio defines the proportional amounts of each component in a multi-part mixture, expressed as a series of numbers separated by colons. A 3:1 epoxy ratio means 3 parts resin to 1 part hardener — totaling 4 parts. To mix 1 liter at 3:1, you need 750ml resin and 250ml hardener. Getting the ratio right is critical: incorrect proportions cause epoxy that never fully cures, paint that does not adhere, or concrete that lacks structural integrity.
Mixing ratios appear across countless applications: automotive paint (4:1:1 base:hardener:reducer), construction mortar (1:3 cement:sand), concrete (1:2:3 cement:sand:gravel), bartending cocktails (2:1 spirit:mixer), epoxy resin (2:1 or 5:1 by volume), hair color (1:1 or 1:2 color:developer), and industrial chemical batching. Some ratios specify volume, others weight — always verify which unit system the ratio references for your material.
使用される計算公式・方程式
この計算ツールは5つの主要な公式を使用しています：
1 Component Amount ▼
For 3:1 ratio and 1 gallon total: Part A = 1 gal × (3/4) = 0.75 gal; Part B = 1 gal × (1/4) = 0.25 gal.
2 Total from Component ▼
If Part A is 600ml and ratio is 3:1: Total = 600 × (4/3) = 800ml.
3 Three-Part Mix ▼
For 4:1:1 and 3 liters: Part A = 3 × (4/6) = 2L; Parts B&C = 0.5L each.
Explore all calculation options on the 比率計算ツール home page.
比率計算ツールの使い方
この比率計算ツールは、以下の3ステップで簡単にご利用いただけます：
数値を入力
入力欄に既知の比率の値を入力します。求めたい未知数の入力欄は空欄のままにしておきます。
モードを選択
比率モード（解く、簡素化、スケーリング）を選択します。各モードで異なる計算式が適用されます。
結果を確認
計算するボタンを押します。結果画面に答えと、視覚的な比率バー、円グラフ、詳細なステップバイステップの解決プロセスが表示されます。
実例問題と段階的な解説
本比率計算ツールを使って、以下の3つの例題をステップバイステップで解決するプロセスです：
入力 1 Mix 2-part epoxy at 3:1 ratio for 500ml total
入力 2 Automotive paint: 4:1:1 ratio, need 800ml
入力 3 Mortar mix: 1:3 cement to sand, 50 kg cement available
よくある質問 (FAQ)
What does a 3:1 mixing ratio mean? ▼
A 3:1 ratio means 3 parts of component A to 1 part of component B, totaling 4 parts. For 1 liter total: A = 750ml, B = 250ml. For 1 gallon total: A = 96oz, B = 32oz. Always add ratio numbers together to find total parts before dividing.
How do I mix 4:1:1 automotive paint? ▼
A 4:1:1 ratio means 4 parts base paint, 1 part hardener/activator, and 1 part reducer/thinner — 6 total parts. For 600ml total: Base = 400ml, Hardener = 100ml, Reducer = 100ml. Use a graduated mixing cup for accurate measurement.
What is the concrete mix ratio? ▼
Standard structural concrete uses 1:2:3 (cement:sand:gravel) by volume, which produces approximately 3,000 PSI concrete. High-strength concrete uses 1:1:2. Mortar for bricklaying uses 1:3 to 1:6 (cement:sand). Water content is typically 40-60% of cement weight.
Should I mix by volume or by weight? ▼
Check the product documentation. Most consumer epoxies and paints specify ratios by volume for convenience. Industrial and professional products often specify by weight for accuracy. When in doubt, contact the manufacturer. Weight is generally more accurate because it is not affected by temperature or aeration.
How do I calculate the amount of each component if I only have a fixed amount of one? ▼
Divide your available amount by its ratio number to find the unit part. Multiply the unit part by each other component's ratio number. Example: You have 600ml of resin at 3:1 ratio. Unit part = 600 ÷ 3 = 200ml. Hardener = 1 × 200 = 200ml. Total = 800ml.
What happens if I use too much hardener in epoxy? ▼
Excess hardener can cause the epoxy to cure too quickly, become brittle, develop a cloudy appearance, or produce an uneven surface with amine blush. In extreme cases, the exothermic reaction can generate enough heat to cause smoking or melting of containers. Always follow the exact specified ratio.
How accurate do my measurements need to be? ▼
For epoxy and resin: within 5% by volume or 2% by weight. For paint: within 10%. For concrete: within 10-15% for non-structural, 5% for structural. The more precise your measurements, the more consistent your results. Use graduated containers or scales rather than estimating.
Can I adjust mixing ratios for different conditions? ▼
Generally, no — ratios are chemically determined and should not be changed. However, some adjustable components exist: paint reducer may be increased slightly in hot weather for better flow, and some epoxy systems have variable hardener ratios for different cure speeds. Always follow manufacturer guidelines.
What mixing ratio is best for epoxy resin art? ▼
Most art resin (tabletop epoxy) uses a 1:1 ratio by volume for ease of measurement. Deep pour casting resins often use 2:1 or 3:1 ratios. UV resin is single-component (no mixing required). Always use the ratio specified by your specific resin brand — they are not interchangeable.
How do I convert a ratio to percentage? ▼
Divide each component's parts by the total parts and multiply by 100. For a 3:1 ratio (4 total parts): Component A = 3/4 × 100 = 75%. Component B = 1/4 × 100 = 25%. For 4:1:1 (6 parts): A = 66.7%, B = 16.7%, C = 16.7%.