Calculator Inputs
Example Data Table
| Scenario | Area | Spray Volume | Tank | Rate | Adjuvant per Tank | Total Adjuvant |
|---|---|---|---|---|---|---|
| Backyard beds | 2 ac | 15 GPA | 25 gal | 0.25% v/v | 8.0 oz | 9.6 oz |
| Orchard block | 5 ac | 25 GPA | 50 gal | 1 qt / 100 gal | 0.5 qt | 1.25 qt |
| Vegetable field | 3 ha | 200 L/ha | 400 L | 250 mL / 100 L | 1000 mL | 1500 mL |
These examples are illustrative. Always follow product labels and mixing guidance.
Formula Used
- Percent v/v: Adjuvant = Spray Volume × (Percent ÷ 100)
- Per 100 gallons: Adjuvant = (Spray Volume ÷ 100) × Rate
- Per acre / per hectare: Adjuvant = Area × Rate
How to Use This Calculator
- Enter your treatment area and choose acres or hectares.
- Add your spray volume per area and select the unit.
- Enter your tank size to estimate per-tank dosing.
- Select a rate type that matches your label statement.
- Input the label rate value, then press Calculate.
- Use the export buttons to save or share results.
Why adjuvants matter in spray performance
Adjuvants help droplets spread, stick, or penetrate, improving consistency when leaf surfaces are waxy or water-repellent. Small concentration changes can shift coverage, runoff, and crop safety, so measured dosing matters. For example, a 0.25% v/v surfactant equals 0.32 oz per gallon; a 10-gallon mix needs about 3.2 oz, not guesswork.
Common rate expressions and what they mean
Labels may state percent v/v, ounces per acre, or amounts per 100 gallons. Percent v/v links directly to spray volume, while per-acre rates stay constant across sprayer outputs. Per-100-gallon rates scale with tank fill and carrier volume. Many programs use 0.25–0.50% v/v for nonionic surfactants, 1.0% v/v for MSO blends, or 1 qt per 100 gal for crop oil concentrates (always confirm the label).
Using tank size to prevent under-dosing
The calculator converts your area rate into a per-tank dose using acres covered per tank. This prevents “guess and pour” errors on partial fills and reduces variability between loads. It also reveals when an unusually small tank needs a fine measuring tool, such as a syringe for 5–30 mL additions.
Cost and inventory planning for seasonal programs
When you add a unit cost, the tool estimates total spend for the job. That helps compare adjuvant options, plan purchasing, and avoid running short mid-application. The export report lists totals in gallons, ounces, liters, and milliliters, matching common packaging sizes. Use the conversion references to cross-check: 128 fl oz = 1 gal and 3.785 L = 1 gal. Record batch notes for repeatable field results.
Quality checks before you mix and spray
Confirm nozzle output, pressure, and travel speed so spray volume per area is realistic. Match adjuvant type to the pesticide label and target: surfactants for wetting, oils for penetration, conditioners for hard water, and drift reducers for off-target control. If you switch between acres and hectares, remember 1 ha ≈ 2.471 ac. Always follow label mixing order, use water, and run a jar test when combining products.
FAQs
What does percent v/v mean in this calculator?
Percent v/v is volume of adjuvant per 100 volumes of spray mix. Enter the number shown on the label, such as 0.25 for 0.25% v/v. The tool converts it to per-tank and total amounts.
When should I pick a per-acre rate instead of percent?
Use per-acre rates when the label specifies a fixed amount per treated area. Percent v/v is best when the label ties performance to concentration in the tank. The calculator supports both, using your spray volume to bridge them.
Why does my per-tank dose change when I change spray volume?
Spray volume changes how many acres your tank covers. For per-acre labels, fewer acres per tank means less adjuvant per tank. For percent v/v labels, the per-tank dose depends mainly on tank fill, not acres.
Can I work in liters and hectares?
Yes. Choose hectares for area, L/ha for spray volume, and liters for tank size. The calculator converts everything internally and reports totals in both metric and U.S. units so you can measure with what you have on hand.
My label says “X per 100 gallons.” How do I use that?
Select the matching “per 100 gallons” rate type and enter the label value in ounces, quarts, or pints as stated. The tool scales that rate to your tank size and to the full job’s total spray volume.
Is this a replacement for label directions?
No. This is a planning and measuring aid. Always follow the pesticide and adjuvant labels, local regulations, and safety requirements. If labels conflict, follow the most restrictive guidance and consult an agronomist or extension expert.