SettingsSettings for this calculationUS
The flow rate in cubic metres per hour.
Cubic metres per hour is a throughput figure — what a chiller, an air handling unit, a treatment plant or a borehole delivers over an hour of running. It is an average by construction, so a plant rated at 100 m³/h does not guarantee that rate at every instant, and a pipe sized on the hourly figure alone can be undersized for the peak within the hour.
Flow rate
27.78 L/s
m³/h ÷ 3.6 = L/s (1,000 L per m³ over 3,600 s per hour). Exact by definition. An hourly rating is an average; size pipework on the peak, not on the average.
- Cubic metres per hour entered
- 100 m³/h
- Litres per second
- 27.78 L/s
- Cubic metres per day at this rate
- 2,400 m³/day
They open the calculator with your figures already in it
Cubic Metres per Hour to Litres per Second Calculator: 27.78 L/s — shown in imperial, US market. The link sets both, so the result they see is the one on your screen.
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How this was calculated
Formula source(s)
- SI Brochure, 9th edition — the litre is 10⁻³ m³ and the hour 3,600 s
- NIST SP 811 — accepted non-SI units used with the SI
Inputs used
- Flow rate (m³/h)
- 100
Intermediate steps
- Cubic metres per hour entered
- 100 m³/h
- Litres per second
- 27.78 L/s
- Cubic metres per day at this rate
- 2,400 m³/day
Confidence note: m³/h ÷ 3.6 = L/s (1,000 L per m³ over 3,600 s per hour). Exact by definition. An hourly rating is an average; size pipework on the peak, not on the average.
Add the equipment this sizes
This result is a specification — 27.78 L/s — not a quantity. Put the thing it sizes into your project: how many, what you call it, and your supplier’s price.
Computed in your browser — nothing you enter is uploaded. Presented in US customary units and US trade terminology. Where a formula follows a published standard, that standard and its edition are cited beside it on this page; where none governs, the page says so. Local amendments override model codes — verify against the code in force where you build.
Sources checked 2026-09-12 · v1.0.0
Regulatory standards & verification citations2
- SI Brochure, 9th edition — the litre is 10⁻³ m³ and the hour 3,600 s
- NIST SP 811 — accepted non-SI units used with the SI
Cite this page
Your workspace
Most jobs need more than one number. Add the calculators you need next and they open right here, underneath this one — your figures stay on screen and nothing is lost to a page change.
This is the direction that runs from the equipment schedule to the pipework, and the change of time base is a change of meaning as well as of number. An hourly figure has already smoothed whatever happened inside the hour, so converting it to litres per second produces a per-second number that never actually occurred — it is the average second, not the busy one. The page converts it exactly and then says that plainly, because the next step after this conversion is nearly always a velocity check that will size a pipe, and a pipe sized on an averaged peak is the quiet way to build in a pressure problem that only shows up when the plant is busy.