- How do I calculate oz per gallon for my sprayer tank?
- Find the application rate on the product label — usually expressed as fl oz per gallon of water. Multiply that rate by your tank size: if the label says 2 fl oz/gal and your tank holds 25 gallons, you need 50 fl oz of concentrate. Fill the remainder with water to reach 25 gallons. This calculator does that multiplication automatically and also handles tsp/gal, tbsp/gal, mL/L, and more.
- What is the difference between oz/gal and mL/L, and how do I convert?
- Both express the ratio of concentrate to spray solution. 1 US fluid ounce per US gallon equals 7.8125 mL per litre (because 1 fl oz = 29.5735 mL and 1 gal = 3,785.41 mL, so 29.5735 ÷ 3785.41 × 1000 = 7.8125). So a label rate of 2 oz/gal equals 15.625 mL/L. Use the "Unit Convert" tab above to convert any rate in one click.
- How does the concentration (%) method work?
- Some products (especially glyphosate concentrates like 41% Roundup) specify a target percentage in the spray solution rather than a rate per gallon. The formula is: Concentrate volume = (Target% ÷ Stock%) × Tank volume. For example, a 0.5% solution from a 41% concentrate in a 100-litre tank requires (0.5 ÷ 41) × 100 = 1.22 litres of concentrate and 98.78 litres of water.
- What is a tank mix and how do I calculate it?
- A tank mix combines two or more pesticide products in a single spray load — for example, an herbicide plus an adjuvant or a fungicide. The "Tank Mix" tab lets you enter each product with its own rate and unit. The calculator shows the volume of concentrate needed for each product separately, plus the total concentrate and remaining water volume. Always check the product labels to confirm compatibility before mixing.
- What is a spray (application) log and why do I need one?
- Many jurisdictions require licensed applicators to keep records of each pesticide application: date, location, product used, rate, and target crop or pest. Even for home gardeners, a log helps you track what worked, avoid over-application, and meet re-entry interval requirements. This tool's spray log stores entries in your browser's LocalStorage (nothing is uploaded) and lets you export a CSV file compatible with Excel or Google Sheets.
- How do I convert a dilution ratio like 1:19 to oz/gal or mL/L?
- A 1:19 dilution means 1 part concentrate per 19 parts water — so 1 part in 20 total, or 5% concentrate. Per US gallon (128 fl oz): 128 ÷ 20 = 6.4 fl oz concentrate. Per litre (1,000 mL): 1,000 ÷ 20 = 50 mL concentrate. The "Dilution ratio" mode in the Single Product tab calculates this for any tank size automatically.