Spray Mix Calculators Herbicide Mixing Calculator
Herbicide Mixing Calculator
Calculate exact herbicide per tank from your label rate and gallons per acre. Works for any boom sprayer, backpack, or ATV sprayer. Supports tank-mix partners, full job planning, and side-by-side product cost comparison.
💡 Three tools in one:
- Tank Mix — label rate + GPA + tank size → exact oz per tank, with optional second product
- Job Planner — adds total acres and price → tanks, product quantity, containers to buy, total cost
- Compare Products — two herbicides side-by-side on rate, cost per acre, and total job cost
Works for any herbicide with an oz/acre label rate — glyphosate, 2,4-D, dicamba, clethodim, triclopyr, atrazine, and more.
On this page: Calculator · How herbicide mixing works · Common rates & GPA reference · Related tools · FAQ
Don't know your GPA yet? Measure it with our Sprayer Calibration Calculator · Want cost per acre only? Spray Cost Per Acre Calculator · Mixing multiple products? WALES Mixing Order Guide
Herbicide Mixing Calculator
Start with the Tank Mix tab to get oz per tank. Use Job Planner for full purchase planning, or Compare Products to find the better value.
Product A — Label Rate
Sprayer Settings
Tank-Mix Partner (optional)
Tip: Don't know your GPA? Measure it first with our Sprayer Calibration Calculator.
Plan your full application — how many tanks you need, how much product to buy, and what it will cost.
Label Rate & Sprayer
Job Size
Product Cost (optional)
Compare two herbicides side-by-side — same target, different products or rates. Enter rates and prices for both to find out which costs less per acre and per job.
Product A
Product B
Job Size (optional — for total cost comparison)
Common herbicide rates & GPA reference
Typical label rates for common herbicide types. Always use your specific product label — rates vary by formulation, concentration, and target species.
| Herbicide type | Typical rate | oz per tank at 20 GPA / 100 gal | Notes |
|---|---|---|---|
| Generic glyphosate (41%) | 16–32 fl oz/acre | 80–160 fl oz | Annual and perennial broadleaf and grass weeds |
| 2,4-D amine | 16–32 fl oz/acre | 80–160 fl oz | Broadleaf weeds in grass crops and non-crop areas |
| Dicamba (3.73 lb/gal) | 8–16 fl oz/acre | 40–80 fl oz | Often tank-mixed with glyphosate; drift-sensitive |
| Clethodim (2 EC) | 6–16 fl oz/acre | 30–80 fl oz | Selective grass killer in broadleaf crops |
| Atrazine (4 lb/gal) | 1–2 qt/acre | 10–20 qt | Corn and sorghum — pre- and post-emergent |
| Triclopyr (4 lb/gal) | 1–4 pt/acre | 5–20 pt | Woody plants, vines, and broadleaf brush |
| Imazapyr | 4–48 fl oz/acre | 20–240 fl oz | Wide range for industrial and forestry use |
Rates shown are illustrative typical ranges. Always refer to your product label for the correct rate, timing, and tank-mix requirements. The label is the law.
Typical GPA by sprayer type
| Sprayer type | Typical GPA range | Notes |
|---|---|---|
| Boom sprayer (field crops) | 10–25 GPA | Most common for row crops; 15 GPA is a typical starting point |
| Boom sprayer (turf & pasture) | 15–40 GPA | Higher GPA improves coverage on dense canopy |
| Backpack sprayer (spot treatment) | 20–60 GPA | Highly variable by walking speed and nozzle type; calibration is essential |
| ATV/UTV boom | 15–30 GPA | Balance of coverage and acres per tank |
| Airblast (orchards) | 50–200 GPA | High volume needed for canopy penetration |
| Drone (UAS) | 0.5–2 GPA | Ultra-low volume; requires specialist nozzles and calculation — see Drone Calculator |
Not sure of your GPA? Use the Sprayer Calibration Calculator to measure it directly.
Frequently asked questions
How do I mix glyphosate in my spray tank?
Glyphosate labels express the rate in fl oz per acre, not as a mixing ratio — so the amount you add depends on your tank size and how many gallons per acre (GPA) you apply. For a typical generic 41% glyphosate at 32 fl oz/acre with a 20 GPA sprayer and a 100-gallon tank: (32 ÷ 20) × 100 = 160 fl oz per tank, covering 5 acres. Enter your own rate, GPA, and tank size in the Tank Mix tab above to get the exact amount for your setup. The same method works for 2,4-D, dicamba, clethodim, triclopyr, and any other herbicide with an oz/acre label rate.
How do I calculate how much herbicide to put in my spray tank?
Use the formula: oz per tank = (label rate oz/acre ÷ GPA) × tank gallons. For example, 32 fl oz/acre label rate, 20 GPA, 200-gallon tank: (32 ÷ 20) × 200 = 320 fl oz per tank. The Tank Mix tab above does this instantly for any rate unit, with acres-per-tank shown automatically.
What is GPA and how does it affect my tank mix?
GPA (gallons per acre) is your carrier rate — the total spray volume applied per acre. It controls how dilute the mix is in your tank, but does not change how much active ingredient reaches each acre (that is fixed by the label rate). Lower GPA means more product per gallon of water; higher GPA means a more dilute tank. Don't know yours? The Sprayer Calibration Calculator will measure it for you.
How many acres does one spray tank cover?
Acres per tank = tank size ÷ GPA. A 200-gallon tank at 20 GPA covers 10 acres. At 15 GPA it covers 13.3 acres. The calculator shows this alongside your per-tank herbicide amount on every calculation.
Can I mix two herbicides in the same tank?
Yes — use the tank-mix partner option in the Tank Mix tab. Enter each product's label rate separately; the calculator shows how much of each to add per tank and the combined fl oz total. Always verify compatibility with both product labels before mixing — some herbicides are not compatible and can reduce efficacy or cause crop damage. In general, add products in this order: half-fill with water → dry formulations → liquid concentrates → adjuvants → top up with water.
How much herbicide do I need to buy for my job?
Use the Job Planner tab. Enter your label rate, GPA, tank size, and total acres. Add product price and container size to see total product needed, number of containers to purchase (rounded up), cost per acre, and total product cost.
How do I compare a generic vs a branded herbicide with different rates?
Use the Compare Products tab. Enter each product's label rate, price, and container size. The calculator normalises both to cost per acre, accounts for the difference in application rate between the two formulations, and highlights the cheaper option with the savings per acre and total job savings.