I built LawnSuite because I kept doing lawn maths in a notebook: how big is the patch, what does the label say, and what did the last watering weather actually look like? For me, a subscription makes sense only when it removes a recurring bit of that work. An app existing is not enough.

The headline rounds the Founding price to five dollars. The advertised price is $4.99 a month (renews at $4.99 a month) or $49.99 a year (renews at $49.99 a year) in AUD. Pro is $14.99 a month or $149.99 a year. These amounts match the current price catalog; renewal terms are part of the 2 October 2026 Founding offer update. See pricing for the offer and terms.

Here is the honest version of the maths: the water table below is a set of modelled city scenarios from the FAO-56 comparison. It is useful for understanding the size and spread of a question. It is not a promise that LawnSuite will save you the amount in the table, and it is not a subscription payback calculation.

What the water model says by city

The model compared a defined 25 mm-a-week benchmark with a weather-and-rainfall water balance for a 150 m² example lawn. It calculated each year's monthly shortfalls before averaging them, then applied the sourced residential usage prices where the pack had a FY2026–27 tariff. The values below are the model's annual AUD difference range, tier-one to top-tier where both were sourced.

City Model's annual water-cost scenario
Brisbane $570–$711
Sydney $447
Melbourne $392–$500
Perth $128–$320
Adelaide $196–$303
Canberra $341–$686
Hobart $189
Darwin $139

Read those as modelled ranges, not money you can count on recovering. The scenarios use FY2026–27 usage prices, leave out fixed charges and sewerage, and do not describe your meter, sprinkler, rainfall timing or watering roster. Perth now uses Water Corporation's checked FY2026–27 metropolitan residential marginal prices, 2.108–5.256 AUD/kL. At tier 1 the $128 scenario is below Pro's annual price; at the top tier the $320 scenario is above it. These are defined marginal-price scenarios, not a forecast of your bill.

Here is where the annual plan prices sit beside those modelled ranges. They compare two water scenarios; they do not measure the app's effect.

City Modelled annual range Founding $49.99/yr (renews at $49.99/yr) Pro $149.99/yr
Brisbane $570–$711 Plan costs less Plan costs less
Sydney $447 Plan costs less Plan costs less
Melbourne $392–$500 Plan costs less Plan costs less
Perth $128–$320 Plan costs less Depends on tariff scenario
Adelaide $196–$303 Plan costs less Plan costs less
Canberra $341–$686 Plan costs less Plan costs less
Hobart $189 Plan costs less Plan costs less
Darwin $139 Plan costs less Plan costs more

Pro's $149.99 a year is more than Darwin's $139 scenario and Perth's tier-1 $128 scenario. Other displayed scenarios are larger than either annual plan price — still a modelled water difference, not a saving you can bank.

A Brisbane range of $570–$711 is larger than either listed annual plan price. That is an arithmetic comparison, not evidence that the app caused that water difference. The model compares two water scenarios; it does not observe what you would have done before installing LawnSuite. Sydney, Hobart and Darwin show one sourced tariff scenario rather than a false precision range. If you do not irrigate, the water column may have little to say about your household at all.

The FAO-56 pillar explains the assumptions, the rainfall credit, and why equal annual totals can still put water in the wrong month. A monthly climate comparison cannot see a dry spell inside the month or tell your local authority's watering roster what to permit.

The other maths: a bag bought versus a bag needed

This is where measuring your lawn matters more than rounding a bag label in your head. The public label-rate calculator asks you to supply the amount printed on your own current label and the area you measured. It does not choose a product or supply a typical rate.

Use this paper version first:

  1. Write down the label amount R and the label area A, keeping each unit from your own current label.
  2. Measure your lawn area as M, then convert M to the same area unit as A before calculating. 1 ha = 10,000 m²: if A is in hectares and M was measured in square metres, divide M by 10,000 to get hectares.
  3. The amount needed is Q = R × M ÷ A. Q is in the label amount's quantity unit: if R is in grams, Q is in grams; if R is in kilograms, Q is in kilograms.
  4. Before calculating bags, express Q and the amount in one bag, B, in the same quantity unit. 1 kg = 1,000 g: for bags measured in kilograms, divide a gram quantity by 1,000. Do not treat grams as millilitres: converting between mass and volume requires a product-specific conversion from the label or manufacturer. If you cannot establish compatible units, stop the calculation. Then calculate bags to buy = ceil(Q ÷ B), where ceil means round up to a whole number. Round up the bag purchase only, not the amount to apply.
  5. The unused remainder across all purchased bags is ceil(Q ÷ B) × B − Q, in the same units as B. An exact multiple of the bag amount leaves zero remainder.

For a worked purchase example, suppose your own label-based calculation has already given the amount below. These are arithmetic examples, not product rates or application recommendations:

Amount needed, converted to bag units Amount per bag Bags to buy Unused remainder
15,000 g = 15 kg 10 kg 2 5 kg
20,000 g = 20 kg 10 kg 2 0 kg

For the first row, two bags contain 20 kg, so the remainder is 2 × 10 kg − 15 kg = 5 kg. For the second, the amount needed is an exact two-bag multiple, so nothing remains.

Your label supplies R and A, your measured lawn supplies M, and the bag supplies B. LawnSuite or the public calculator can do the multiplication; neither can decide whether the material is suitable for your lawn or replace the label. Use the label values you supplied; the calculator only does the arithmetic. No product name or label figure belongs in a value calculation without the reader's own label and context.

The useful check here is avoiding a made-up area. If you have a small patch, a bag bought is not automatically a bag needed. If the result is larger than one bag, the same calculation tells you before you open anything. The calculator shows the entered unit and a paired scale from the same unrounded quantity so you can choose a readable way to measure it.

When an app is probably not for you

I would not pay for LawnSuite just to make the maths look more official. It is a poor fit when:

  • you have no irrigation and do not intend to add or measure any;
  • your lawn is a tiny courtyard where the public tools and a note on your phone cover the occasional calculation;
  • your lawn is rain-fed and you are not managing a recurring water balance;
  • you only need a one-off area measurement or a one-off label calculation.

The free lawn-area tool and public label calculator may be enough. The paid app becomes a more plausible fit when you want to keep lawn areas and observations together, revisit a weather-aware water estimate, and carry the same inputs through repeated decisions. That is a workflow judgement, not a guarantee of a dollar return.

What I would check before paying

Start with the recurring job. Is it water, remembering what you did, or scaling a label amount to a measured area? If the answer is “none”, stay with the free tools. If the answer is “all three”, use the free versions first and see whether they fit your weekend.

Then compare the plan price with your own evidence, not the largest number in the city table. Keep a note of the area you measured, the rain you actually received and the decisions you made. If your own record does not show a repeated problem, a subscription is solving a problem you have not established.

If you do want the app, open LawnSuite and check the current offer before joining. Check the current price and availability at signup.

Related guides

About Macca: I built LawnSuite and its FAO-56 water-balance engine, and I run it on my own Ipswich lawn. I read the inputs closely because I want the arithmetic to be visible when I make a decision on my own patch.

Weather, treatment history, and doses worked out from the label rate you enter, in one app. Built for Australian lawns.

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