Foam vs. Liquid Hand Soap: Cost Per Wash, Using the Dispenser's Own Numbers
Foam soap dispensers are built to use less liquid per wash than a standard pump, and the manufacturer will tell you exactly how much — Dial's own dispenser brochures publish a dose of 0.4 to 1.1 mL per pump depending on the model and formula. A standard liquid pump has no such published number, because it isn’t a sealed metering system — its output depends on the pump head, how full the bottle is, and the soap’s own thickness. That doesn’t mean liquid can’t be compared fairly. It means you measure it yourself, which takes about five minutes, and this page shows you how, then turns both numbers into a cost per wash you can trust more than a rule of thumb.
What a foam dispenser actually uses — the manufacturer's own numbers
Dial Professional (Henkel) publishes per-actuation dose and uses-per-refill figures in its own dispenser brochures for two different foam systems:
| Dispenser | Formula | Dose/pump | Refill size | Washes/refill |
|---|---|---|---|---|
| Dial FIT (touch-free) | Foaming hand wash | 0.8 mL | 1.0 L | 1,250 |
| Dial FIT (manual) | Foaming hand wash | 0.8 mL | 1.2 L | 1,500 |
| Dial 1700 | Basics foaming soap | 0.4 mL | 1.7 L | 4,250 |
| Dial 1700 | Complete foaming soap | 0.8 mL | 1.7 L | 2,125 |
Source: Dial Professional FIT and 1700 dispenser brochures, dialprofessional.com, retrieved 2026-09-27. Gel sanitizer in the same FIT dispenser doses at 1.1 mL/pump — a reminder that a thicker formula gets a bigger dose even from the same machine.
The spread inside just one brand — 0.4 to 0.8 mL per pump — is the first thing the old flat claim “foam always wins” missed. Which foam system you have changes the math by up to 2× before liquid ever enters the comparison.
What a liquid pump actually uses — measure it, because nobody publishes it
Foam systems are sealed, metered cartridges, so the dose is an engineering spec the manufacturer controls and can publish. A standard bulk liquid dispenser is an open mechanical pump — its output depends on the stroke length of that specific pump head, the thickness of the soap you put in it, and how much liquid is left above the pump. No manufacturer, Dial included, publishes a per-push mL figure for these the way they do for a foam cartridge.
Measure your own in about five minutes:
- Get a 1 oz (30 mL) portion cup or a shot glass marked at 30 mL.
- With a full bottle, pump the dispenser with full, deliberate strokes into the cup and count the pumps until it’s full.
- Divide 30 mL by the pump count. That’s your mL-per-pump for that dispenser, right now.
- Repeat the count when the bottle is about a quarter full. Pump output commonly drops as the liquid level falls, so use the full-bottle number for planning and treat a large drop-off as a sign the pump needs replacing.
Turning both into cost per wash
Once you have a dose in mL for either soap:
Washes per refill = refill volume (mL) ÷ mL per pump
Cost per wash = refill price ÷ washes per refill
Numbers below are an illustrative example — use your own measured pump rate and your own invoice price, not these.
- Foam — Dial FIT manual, 1.2 L refill, 0.8 mL/pump = 1,500 washes/refill. At an example refill price of $9.50, that’s about $0.0063 per wash.
- Liquid — a 1-gallon (3,785 mL) refill measured at 1.4 mL/pump = about 2,703 washes/refill. At an example refill price of $14, that’s about $0.0052 per wash.
In this example the larger liquid refill actually comes out a little cheaper per wash than the smaller foam cartridge — the opposite of what a flat “foam always wins” rule would tell you. Change the refill size, the price, or the measured pump rate and the answer can flip back. That’s the whole point of running your own numbers instead of trusting a rule of thumb: on a different bottle, a different price, or a pump nearing the end of its life, the cheaper option can go either way.
A 50-employee office, both ways
Our per-employee cost build uses 42 handwashes per person per month as a labelled planning assumption. At 50 employees, that’s 2,100 washes a month, split across however many restrooms and dispensers a building runs.
- Foam (Dial FIT manual, 1,500 washes/refill): 2,100 ÷ 1,500 ≈ 1.4 refills a month — call it 2 cartridges most months, roughly 17 a year with some buffer.
- Liquid (measured example, 2,703 washes/gallon): 2,100 ÷ 2,703 ≈ 0.78 gallon a month — roughly one gallon every six weeks.
Substitute your own dispenser's measured pump rate, your own refill size and your own invoice price and this table rebuilds itself around your restrooms, not a generic office.
What the cost-per-wash number doesn't capture
A few things sit outside the arithmetic and still belong in the decision:
- Mess and drain buildup — a liquid pump is easier to over-dispense than a fixed-dose foam pump, and the excess ends up on the counter or down the drain rather than on hands.
- Dispenser cost — switching soap types can mean buying new dispensers across every restroom, which is a one-time cost the per-wash math doesn't include.
- Tamper and contamination resistance — a sealed cartridge can't be topped off with an unknown product the way an open bottle can.
- Handwashing effectiveness — comes from technique and contact time, not lather volume; neither format washes hands better than the other on its own.
Which should you choose?
If you're already running foam dispensers, get the dose and refill numbers for your exact model from the brochure before assuming the cartridge is the cheap option — the 2× spread between Dial's own two foam lines shows it isn't automatic. If you're running liquid, the five-minute measurement above is the only way to know your real number, since no one publishes it for you. Either way, run both sides through the worksheet on your own invoice before switching formats on a cost argument alone.
FAQ
Is foam soap always cheaper per wash than liquid soap?
Not always. Foam dispensers use a smaller dose by design, but the actual cost per wash depends on the refill price and refill size for the exact products you buy. Run both numbers through the worksheet on this page before assuming foam wins — in our own worked example, a large liquid refill came out slightly cheaper per wash than a small foam cartridge.
How much soap does a foam dispenser actually use per pump?
It depends on the dispenser. Dial's own published brochures show 0.4 mL per pump on its 1700 Basics foaming system, 0.8 mL per pump on its FIT and 1700 Complete foaming systems, and 1.1 mL per pump for gel sanitizer in the same FIT dispenser. There is no single foam number — check the brochure for your specific dispenser and formula.
How do I find out how much my liquid dispenser dispenses per pump?
Manufacturers don't publish a per-pump volume for standard manual liquid pumps the way they do for sealed foam cartridges. Fill a 1 oz (30 mL) portion cup, count how many full pumps it takes to fill it, then divide 30 by that count. Do it once with a full bottle.
Does pump output change as the bottle empties?
It commonly drops, because a liquid pump relies partly on the head of liquid above it. Measure again when a bottle is about a quarter full if you want to see how much your specific dispenser's output falls off, and use the fuller-bottle number as your planning baseline.
Do I need a special dispenser to switch to foam?
Yes. Foaming soap requires a dispenser built to mix soap with air as it pumps — a standard liquid dispenser will not produce foam. Sealed cartridge systems also resist tampering and refilling with an unknown product.