Calculator
Example data table
| Project | Area (m²) | Rate (m²/hr) | Time (hr) | Solution (L) |
|---|---|---|---|---|
| Greenhouse aisle wash | 28 | 40 | 0.70 | 1.00 |
| Patio algae removal | 45 | 30 | 1.50 | 1.80 |
| Shed floor degrease | 12 | 35 | 0.34 | 0.45 |
Figures above are illustrative. Your results depend on overlap, waste, dilution, and coverage settings.
Formula used
- Base area: rectangle = L × W, circle = π × r², triangle = 0.5 × base × height.
- Effective area: base area × (1 + overlap%) × (1 + waste%).
- Time: effective area ÷ cleaning rate.
- Ready-to-use solution: effective area ÷ coverage per liter.
- Dilution split: concentrate = solution × C/(C+W), water = solution × W/(C+W).
- Cost: chemical cost = concentrate × price; labor cost = hours × labor rate.
How to use this calculator
- Select Use dimensions for repeated areas, or Enter total area if you already measured it.
- Pick a shape and enter measurements in your preferred unit.
- Adjust overlap and waste for rough floors and obstacles.
- Set cleaning rate and solution coverage based on your tool and product.
- Enter dilution ratio and costs to estimate concentrate, water, and budget.
- Click Calculate, then download CSV or PDF for records.
Why accurate floor area matters for outdoor cleaning
Garden spaces often include patios, potting sheds, greenhouse aisles, and walkways with mixed surfaces. Accurate floor area prevents under-mixing solution and reduces mid-job refills. It also helps you size tools, estimate rinse water needs, and avoid over-scrubbing delicate sealers. When projects include multiple similar sections, repeating dimensions with a quantity produces a cleaner plan than guessing totals.
Choosing the right shape and measurement approach
Most slabs and decks are rectangles, but circular tank pads and triangular corners are common around raised beds. Use dimensions when you can measure length and width, or base and height for a triangular wedge. If the site is irregular, measure it in zones and enter the combined area directly. Converting all inputs to square meters keeps calculations consistent across units.
Cleaning rate and overlap are performance drivers
Cleaning rate is your productivity in square meters per hour, influenced by soil load, grout lines, and equipment. A stiff brush and bucket may be slower than a pump sprayer plus scrub pad. Overlap accounts for extra passes on algae, stains, and textured pavers. Raising overlap produces a safer estimate when surfaces demand multiple applications and agitation.
Solution coverage and dilution planning
Coverage per liter depends on nozzle pattern, surface absorption, and how wet you keep the floor. Use product guidance as a baseline and adjust after a small test patch. Dilution ratio splits ready-to-use solution into concentrate and water volumes, making it easier to stage containers before starting. This reduces waste and helps maintain consistent strength across the job.
Cost forecasting and practical job notes
Material cost comes from concentrate liters multiplied by your price per liter. Labor cost is hours times your hourly rate. Together they provide a quick budget and a way to compare methods, such as pre-soak versus repeated scrubbing. Add a modest waste allowance for edges, furniture moves, and rinsing. For safety, keep runoff away from edible beds and store chemicals securely.
FAQs
1) What overlap percentage should I use for algae or mildew?
Start with 5–10% for light growth. Use 10–20% when you expect repeated passes, dwell time, and agitation on textured pavers or grout lines.
2) How do I estimate cleaning rate if I have no data?
Time a small area, like 10 m², using your real method. Convert minutes to hours and scale up. Enter that rate to get a realistic project duration.
3) Does coverage per liter change with surface type?
Yes. Porous concrete and unsealed pavers absorb more, reducing coverage. Smooth sealed tiles spread solution farther. Adjust after a test patch for accuracy.
4) How should I handle irregular shapes?
Break the floor into simple zones, measure each zone, and sum the areas. Then use the direct area option to enter the combined total.
5) What dilution ratio format is supported?
Use concentrate:water like 1:10 or 1:20. The calculator splits ready-to-use liters into concentrate and water based on those parts.
6) Can I estimate materials only without labor cost?
Yes. Set labor rate to 0. The results will still show time, total liters, concentrate, water, and chemical cost for planning purchases.