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Gallons per acre to liters per hectare, and other US to metric spray conversions

Multiply gallons per acre by 9.35 to get litres per hectare; divide L/ha by 9.35 to get GPA. 15 GPA is 140.31 L/ha, and 200 L/ha is 21.38 GPA.

2 min read · Updated 2026-09-07

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Where 9.35 comes from

A US gallon is 3.785411784 litres and an acre is 0.40468564224 hectares, both exact definitions. Dividing one by the other gives 9.354 litres per hectare for each gallon per acre. SprayMaster uses the full factors, not the rounded 9.35, so its results do not drift on big numbers.

Common spray conversions

US and metric spray conversions, Rate Converter factors
You haveConverts to
1 GPA9.35 L/ha
10 GPA93.54 L/ha
15 GPA140.31 L/ha
20 GPA187.08 L/ha
200 L/ha21.38 GPA
0.4 GPM1.51 L/min
6 mph9.66 km/h
10 acres4.05 ha

Convert with the Rate Converter

  1. Open Rate Converter from Pro Calculators (it needs SprayMaster Pro).
  2. In Conversion, pick from the US ↔ metric group: gal/acre to L/ha, GPM to L/min, mph to km/h or acre to ha.
  3. Tap Direction to convert from the metric side, for example L/ha to GPA.
  4. Type the number in Value and read the Result.

The footer of the screen lists the factors it uses: 1 acre = 43,560 ft² = 0.4047 ha, 1 gal = 128 fl oz = 3.7854 L, 1 mile = 1.6093 km.

Skip converting: calibrate and mix in metric

If your labels are in L/ha and your boom is in centimetres, run every calculator in metric instead of converting back and forth. Set Units to Metric on any calculator or in Settings; the choice sticks on every screen and next launch.

  • Tank Mix offers Per Hectare, Per 100 m² and Per Litre, with tank size in litres and application rate in L/ha. Metric Tank Mix is free.
  • Sprayer Calibration takes L/min, km/h and cm. At 1.2 L/min, 8 km/h and 50 cm spacing it shows 180 L/ha, with 19.24 GPA on the Same rate in line.
  • Area / Acreage takes metres and gives Hectares.

When you switch units, the app resets the product unit to fl oz or mL and the nozzle spacing to 20 in or 50 cm, rather than carrying numbers across, which is easy to miss when flipping units mid-job. Re-enter your values after the switch.

What it does not convert

  • No lb/acre to kg/ha, and no oz/gal to mL/L.
  • No ppm and no active-ingredient maths.
  • No pints, quarts or tablespoons: product units are labels in Tank Mix, not converted.

Questions and answers

How do I convert GPA to L/ha?
Multiply by 9.35 (exactly 3.785411784 ÷ 0.40468564224). 15 GPA is 140.31 L/ha.
How do I convert L/ha to GPA?
Divide by 9.35. 200 L/ha is 21.38 GPA.
Is metric mode free?
Yes. The US / metric switch works in every free calculator. The Rate Converter itself is part of SprayMaster Pro.
Can it convert pounds per acre to kilograms per hectare?
No. The nine conversions cover gal/acre to L/ha, GPM to L/min, mph to km/h and acres to hectares, plus the per-acre to per 1,000 ft² and percent conversions.

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