Product Dose for a 16 Litre Backpack Sprayer

The label decides what goes into a 16 litre knapsack, and it writes the dose one of two ways: per litre of water, or per area.

Label says mL per litre

One multiplication, rate times 16. The 6 mL per litre figure here is made up, so nobody reads it as advice on a real product.

Hypothetical label rates, full 16 L tank
Label rate	Product for 16 L	Percent solution
2 mL per litre	32 mL	0.2%
5 mL per litre	80 mL	0.5%
6 mL per litre	96 mL	0.6%
10 mL per litre	160 mL	1%
20 mL per litre	320 mL	2%

Labels written in cc mean the same thing as mL; 1 cc is 1 mL.

Open Mix Ratio from Calculators. It is free.
Set Units to Metric. The product unit resets to mL.
Under Dilution, type your label rate in Label Rate and leave Product Unit on mL.
Type 16 in Tank Size.
Read Product to Add and Percent Solution under Mix, then tap Save if you want it in History.

With 6 in Label Rate it shows 96 mL and 0.6%. At 80 mL per litre, a big number, it stays in mL (1,280) rather than flipping to litres. That's fine, but read it twice.

Label says per 100 m²

A per-area label gives no tank dose until you know your spray volume, and this is where too much product often gets tipped in. Measure it. Spray plain water over a marked 100 m² at your normal walking pace and see how much is gone. Say 5 litres, which is 500 L/ha.

At 5 L per 100 m², one 16 L tank covers 320 m². With a hypothetical 12 mL per 100 m², that tank takes 12 × 3.2 = 38.4 mL. Same label, but at 8 L per 100 m² you cover only 200 m² per tank and use 24 mL.

In the app this is Tank Mix, not Mix Ratio. Set Units to Metric, Rate Basis to Per 100 m², then type Label Rate 12, Tank Size 16 and Application Rate 500 (L/ha). Product per Tank reads 38.4 mL and Covers per Tank 0.032 ha. Turn on Size a whole job and put your area in Total Area (in hundreds of m², so 1,000 m² is 10) for Tanks for Job, which is a decimal, not rounded up to whole tanks. For a plain per-litre label, Mix Ratio is the simpler choice; the extra fields only pay off when the label is per area.

Half-full tanks

Nobody sprays 16 litres of a small weed patch. Type what you will actually mix as Tank Size: 10 litres at 6 mL per litre is 60 mL. The app does not assume the tank is full.

Where it falls short

One limitation: there is no water line shown. The app shows the product to add, not the water, so you fill to the 16 L mark on the tank yourself, after adding the product to a part-filled tank. It also does not know what is in the bottle: no product list, no rates. And it gives mL or L as typed, no conversion to caps or spoons.

Mix Ratio and Tank Mix are free, with a banner on the home list and a full-screen ad every third time you open either. Sprayer Calibration, the Rate Converter and Area / Acreage need SprayMaster Pro. It runs on iPhone only, with no signal needed.

Questions and answers

How many mL per litre is a 16 litre backpack tank?

Whatever the label says, times 16. A label rate of 5 mL per litre means 80 mL for a full 16 L tank.

Is 1 cc the same as 1 mL?

Yes. Labels that say cc per litre mean mL per litre, and you type the number straight into Mix Ratio with the product unit on mL.

Does the app tell me the dose of my product?

No. It ships no product rates and makes no recommendations. You type the rate from your label and it does the multiplication.

My label is per hectare. Can I use a 16 litre sprayer?

Yes, but you need your sprayer's own output in litres per hectare. Measure it with water, then use Tank Mix with Per Hectare and that figure as Application Rate.

Does it work offline?

Yes. The arithmetic runs on the phone, so a field without signal is fine.

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How much product goes into a 16 litre backpack sprayer?