Calculator
Example data
| Scenario | Rate (oz/gal) | Tank size (gal) | Tanks | Total ounces needed |
|---|---|---|---|---|
| Foliar feed mix | 1.0 | 2 | 1 | 2.0 oz |
| Pest control spray | 0.5 | 4 | 2 | 4.0 oz |
| Soil drench | 2.0 | 1 | 3 | 6.0 oz |
| Spot treatment | 0.25 | 1 | 1 | 0.25 oz |
These are generic examples. Always verify label rates and plant tolerance.
Formula used
- Total ounces: Total_oz = Rate_oz_per_gal × Total_gal
- Total gallons: Total_gal = Gallons_per_tank × Tanks
- Convert oz/gal → mL/L: mL_per_L = (oz_per_gal × mL_per_oz) ÷ L_per_gal
- Convert mL/L → oz/gal: oz_per_gal = (mL_per_L × L_per_gal) ÷ mL_per_oz
Conversions use your chosen gallon and fluid ounce definitions. US gallon = 3.785411784 L. Imperial gallon = 4.54609 L.
Why ounces-per-gallon matters in garden mixing
Accurate ounces-per-gallon dosing helps you deliver consistent nutrition and coverage across beds, containers, and greenhouse benches. A small error compounds quickly when you scale to multiple tanks, and it can lead to poor growth, leaf burn, or wasted product. This calculator standardizes your rate, multiplies it by total gallons, and returns both fluid ounces and milliliters so you can measure with the tools you own.
Conversion benchmarks you can trust
Unit conversions should be anchored to fixed constants. A US gallon equals 3.785411784 liters, while an Imperial gallon equals 4.54609 liters. A US fluid ounce equals 29.5735295625 milliliters, and an Imperial fluid ounce equals 28.4130625 milliliters. By selecting the gallon and ounce types that match your equipment, you avoid subtle drift in mixes, especially when you compare label instructions written for different regions.
Batch planning for sprayers and watering cans
Most gardeners mix in repeatable container sizes: 1‑gallon jugs, 2‑gallon pump sprayers, 4‑gallon backpack tanks, and 15‑ to 25‑gallon carts. Enter your tank size and the number of tanks to compute a single total, which is ideal when you are pre-measuring concentrate before filling. The tool also supports reverse calculation: if you already used a known amount of concentrate, it can derive the implied oz/gal rate for auditing.
Reducing dosing error with better measuring
Precision is easiest when you use the right scale for the dose. For small rates, measuring in milliliters reduces rounding and improves repeatability, because many syringes and graduated cylinders read in 1 mL steps. For larger rates, a marked measuring cup is convenient. The calculator lets you set decimal places, so you can match your measurement resolution without pretending to be more accurate than your tools allow.
Recordkeeping for repeatable results
A mixing log prevents guesswork. Exporting CSV supports spreadsheets and inventory tracking, while the PDF report is useful for printing and attaching to sprayers. Record the product name, target crop, weather notes, and observed results alongside the calculated rate. Over time, these notes help you replicate successful treatments and spot patterns when plants respond differently across seasons.
FAQs
What does oz/gal mean for garden products?
It’s the amount of liquid concentrate, in fluid ounces, mixed into one gallon of water. Multiply the rate by your total gallons to get the total concentrate needed for the batch.
Why does gallon type matter?
US and Imperial gallons have different liter volumes. If your label, measuring jug, or region uses Imperial units, selecting the correct gallon keeps conversions and totals consistent.
When should I use mL/L instead of oz/gal?
Use mL/L when the dose is small or you measure with syringes or cylinders. Metric readings often reduce rounding and improve repeatability for sensitive seedlings and foliar sprays.
Can I calculate the rate if I already used a known amount?
Yes. Choose the rate-from-total mode, enter the total ounces you used, and provide total gallons mixed. The calculator returns the implied oz/gal and mL/L rates.
How accurate are the results?
Math is exact, but real-world accuracy depends on your measuring tools and mixing consistency. Match decimal places to your measurement resolution, and re-check volumes if containers are not precisely marked.
Is this safe for pesticides and herbicides?
The calculator helps with arithmetic only. Always follow the product label, local regulations, and safety gear requirements. If label instructions conflict with your plan, follow the label.
How to use this calculator
- Pick a mode: totals, rate, or conversion.
- Select the gallon and fluid ounce types you use.
- Enter your mix rate and tank volume.
- Add the number of tanks for multiple batches.
- Click Calculate to see totals and conversions.
- Download CSV or PDF to keep a mixing log.
If you are mixing pesticides or herbicides, follow label directions strictly and wear protective gear.