Foam cannon dilution & PIR calculator
Calculate the product and water for your foam cannon bottle from a plain-water calibration and your product’s delivered target.
How to use this calculator
- Set up the pressure washer, nozzle and detergent feed as specified for your product. Fill the reservoir with a measured volume of plain water.
- Collect all discharge until the reservoir empties, then enter the two measured volumes above.
- Use your exact product’s delivered target. Measure the calculated product and add water to the reservoir total.
- Use the same calibrated settings. Recalibrate after changing the washer, lance, nozzle or orifice, pressure, water supply, detergent-feed setting or reservoir fill volume. Check again if solution viscosity or draw changes.
Worked example
A 1,000 mL plain-water reservoir gives 10,000 mL of total collected output. If your product calls for 4% of that output, it needs 10,000 × 0.04 = 400 mL product. Add 600 mL water to fill the reservoir to 1,000 mL. The bottle is 40% product while the calculated delivered output is 4%. These example values are not a recommendation for another product.
Questions about this calculation
What does PIR mean here?
Panel-impact ratio describes the delivered product concentration after the equipment adds water. In this calculator, the target is product volume divided by all collected output, multiplied by 100. A 4% target means 4 parts product in 100 parts total output, or 4 parts product with 96 parts water. It does not mean 4 parts product added to 100 parts water.
Can I enter the dilution printed on my bottle?
Only if it explicitly gives the delivered concentration as a percentage of the total output at the panel. A reservoir recipe, machine dial number, product:water ratio or percentage of water alone cannot be entered directly as this target. Use a product-specific calculator when its instructions use another basis.
Why does my target need more product than the bottle holds?
The measured equipment setting adds too much water to reach that target, even with an undiluted reservoir. Do not overfill or accept a negative water amount. Check the measurements and follow the equipment and product instructions for a supported setting, then recalibrate. Bilt-Hamber specifically discusses this situation in its Auto-Foam guidance.
Does a 1 litre bottle always produce the same dilution?
No. Pressure washers, foam lances, nozzles, water supplies and detergent-feed settings draw different amounts. This tool uses your measurement and assumes it remains consistent during use. Bottle strength alone does not establish delivered strength.
Sources and measurement basis
- Bilt-Hamber Auto-Foam technical sheet — complete-output calibration method
- Bilt-Hamber — when the calculated dose exceeds reservoir capacity
Use the exact current instructions for your product, version and market. Review date: 16 October 2026.