Pesticide dilution & tank mix calculator
Read the rate off the label, get the exact amount of concentrate for your tank. Handles per-gallon, percent-dilution and per-1,000 sq ft rates, liquid or dry.
How does the label state the rate?
Your mix
How the math works
Three ways a label states a rate, and each needs a different calculation. Getting them mixed up is the most common way a tank ends up wrong.
Per gallon — the easy one
"0.5 fl oz per gallon" means exactly what it says: multiply by your tank size. A 25-gallon tank takes 12.5 fl oz. Nothing else enters into it, which is why most product labels aimed at technicians are written this way.
Percent dilution — where the decimal bites
A US gallon is 128 fluid ounces, so a 1% solution is 1.28 fl oz per gallon. The formula:
The trap is that pest control percentages are small. A 0.05% solution is 0.064 fl oz per gallon — under two millilitres. On a 25-gallon tank that is 1.6 fl oz total. Read 0.05% as 0.5% and you have mixed the tank ten times over label rate, which is both a serious label violation and, on a sensitive site, a real liability. When the number lands under a quarter of an ounce per gallon, measure in millilitres.
Per 1,000 sq ft — two steps, not one
An area rate can't be turned into a tank quantity without knowing your spray volume: the gallons of finished solution you actually put down per 1,000 sq ft. Most perimeter and turf work runs about 1 gallon per 1,000 sq ft, but that is your calibration, not a constant — if you have never calibrated, that is the number to go measure.
The tank covers tank ÷ spray volume × 1,000 square feet, and the concentrate for the tank is the label rate multiplied by that area. A 25-gallon tank at 1 gal/1,000 covers 25,000 sq ft, so a 1.5 fl oz per 1,000 rate needs 37.5 fl oz in the tank.
Before you mix
- Check the maximum rate. A legal per-tank number can still break the label's cap on application rate, or its maximum per site per year. The tank math is necessary, not sufficient.
- Wear what the label says. PPE is on the label and is enforceable, and mixing and loading is when concentrate exposure is highest.
- Add water first, then concentrate, then top off — and agitate. Pouring concentrate into an empty tank is how you get it stuck to the bottom and an uneven first few gallons.
- Check compatibility before tank-mixing two products. A jar test costs five minutes; a curdled 25-gallon tank costs an afternoon and the product.
- Mix what you'll use. Leftover finished solution is a disposal problem, not an asset.
- Write it down. Product, EPA registration number, rate, total applied, target, site, date and applicator. Most states require the record within a set window, and the record is what actually protects you in a complaint.
Quick conversions
| 1 US gallon | 128 fl oz |
| 1 quart | 32 fl oz |
| 1 pint | 16 fl oz |
| 1 cup | 8 fl oz |
| 1 tablespoon | 0.5 fl oz |
| 1 teaspoon | ≈ 0.167 fl oz |
| 1 fl oz | 29.57 mL |
| 1 pound | 16 oz (weight) |
| 1 acre | 43,560 sq ft |
Frequently asked questions
How do I calculate a percent dilution for a spray tank?
A US gallon is 128 fluid ounces, so a 0.05% solution needs 128 × 0.0005 = 0.064 fl oz of concentrate per gallon — about 1.9 mL. For a 25-gallon tank that is 1.6 fl oz. The formula is: concentrate (fl oz) = tank gallons × 128 × (percent ÷ 100).
How much area does one tank cover?
It depends on your spray volume — the gallons of finished solution you apply per 1,000 sq ft. Most perimeter and turf applications run about 1 gallon per 1,000 sq ft, so a 25-gallon tank covers roughly 25,000 sq ft. Divide tank size by spray volume to get the area, then multiply the label's per-1,000 rate by that area.
Is it legal to mix at a rate not on the label?
No. Under FIFRA it is a violation of federal law to use a registered pesticide in a manner inconsistent with its labeling, and mixing above the labeled rate is exactly that. Labels also carry a maximum rate per application and often a maximum per site per year, so a legal per-tank number can still be illegal if you exceed the annual cap.
Does this calculator know my product's label rate?
No, and that is deliberate. Label rates change between formulations, target pests, application sites and label revisions, so any stored rate would eventually be wrong for someone. You read the rate off the label in your hand; this converts it into a tank quantity. The arithmetic is the part worth automating — the rate is the part that must come from the label.
Log the mix without the clipboard
PestWarden Pro records product, EPA reg number, rate and target against the stop as the tech closes it — so the chemical log writes itself and is there when the inspector asks.
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