| Sprayer Guru

This free Herbicide Mixing Calculator takes the guesswork out of your sprayer calculations. It’s designed to help you figure out exactly how much herbicide product to mix based on the size of your treatment area and the rate listed on the herbicide label (in ounces per 1,000 square feet).

Use the Herbicide Rate Calculator Below

With this calculator, you can now also enter your tank size in gallons and receive custom mixing instructions—including your water-to-product ratio. It’s the perfect tool for DIY homeowners, acreage managers, and anyone who needs fast, reliable herbicide rate calculations.

Herbicide Mixing Calculator

Lawn size: Unit: Herbicide rate (oz per 1,000 sq ft): Tank size (gallons):

Note: You do not need to apply this amount in a single tank. Most users will refill their sprayer multiple times while treating larger areas. Simply make sure the total amount of herbicide applied across the entire area equals the total amount required according to the calculator.

The amount of water used can vary depending on your sprayer setup and spray volume. Water acts as the carrier. The herbicide rate per area is what matters.

Learn more about spray volume and how much water to use

Who Is This Calculator For?

This tool is ideal for:

Homeowners treating lawns for weeds and pests
DIY lawn care pros using tank, backpack, or hose-end sprayers
Landowners and rural property managers spraying pastures or food plots
Anyone looking to mix liquid herbicides with precision and confidence

RELATED: You can also use this tank fill time calculator to find out how long it will take to fill your sprayer tank.

When to Use It

Use this calculator anytime you need to:

Mix a tank of herbicide for a specific lawn or area
Determine the amount of herbicide to apply per 1,000 sq ft or per acre
Calculate how much product to add to a 1, 2, or 4-gallon sprayer
Get the correct water-to-herbicide mix ratio for your equipment

Herbicide Mixing FAQs & Sprayer Tips

How do I know the right herbicide rate to use?

Always read the label on your herbicide product. Most liquid herbicides list application rates in ounces per 1,000 square feet or per acre. Use those numbers in this calculator to get an accurate mix amount based on the size of your lawn or treatment area.

For more information, see my full guides to spray volume per acre and formulas to calibrate your sprayer.

How much water should I mix with the herbicide?

The amount of water you use depends on your sprayer type and your desired spray coverage, not the herbicide rate. Most herbicides don’t require a specific water volume—they just need to be applied at the correct product rate across the area. For example, if your sprayer applies 1 gallon of mix per 1,000 sq ft, you’d simply dissolve the correct amount of product into that gallon.

Tip: Always do a test spray to see how much area your sprayer actually covers with 1 tank.

Can I use this calculator with selective or non-selective herbicides?

Yes. This herbicide rate calculator works for both selective herbicides (like 2,4-D or weed-and-feed products) and non-selective herbicides (like glyphosate or total vegetation killers). Just make sure you’re using the correct rate based on the label instructions.

Tips for Using Different Sprayer Types

Handheld & Pump Sprayers (1–2 gallons)

Ideal for spot-treating weeds in gardens, driveways, and small lawns.
Calibrate your sprayer by spraying a known area and measuring how much liquid it uses.
Mix only as much as you plan to use that day.

Backpack Sprayers (4 gallons)

Great for medium-sized lawns or larger spot treatments.
Label each sprayer with dedicated use (herbicide only, insecticide only, etc.) to avoid contamination.
Rinse thoroughly between uses to extend sprayer life.

ATV & Pull-Behind Sprayers (15–25+ gallons)

Best for large lawns, acreage, or pasture work.
Use a pressure regulator on the sprayer for even coverage.
Calibrate the sprayer before you mix your pesticide/herbicide

Herbicide Mixing Calculator – Simple Sprayer Calculations for Your Lawn or Garden