Injector flow converter: cc/min ↔ lb/hr

Injector flow ratings come in two dialects: most flow sheets and bench reports quote cubic centimetres per minute (cc/min), while most tuning software and US catalogues quote pounds per hour (lb/hr). This converter moves between the two using the long-standing gasoline conversion below — no black box, the formula is printed right under the tool.

Flow value

Entered in

Live result — it updates as you type. Ratings assume the injector is fully open (static flow) at its rated test pressure, on gasoline.

The formula

lb/hr = cc/min ÷ 10.5 · cc/min = lb/hr × 10.5

The 10.5 factor comes from the density of gasoline: one US gallon of gasoline weighs about 6.07 lb and holds 3,785 cc, so an injector flowing 10.5 cc/min delivers 630 cc per hour — very close to one pound of gasoline per hour. It is the convention used by major injector manufacturers on their published conversion charts, which is why flow sheets from different benches stay comparable.

Worked example (pre-filled above): 500 cc/min ÷ 10.5 = 47.6 lb/hr. Going the other way, a 42 lb/hr injector is a 441 cc/min injector (42 × 10.5).

What to watch for

Test pressure matters. A rating is only valid at the pressure it was measured at (commonly 43.5 psi / 3 bar). If your rail runs a different pressure, correct it with our flow-at-pressure calculator.
Static vs pulsed. Published flow is static (held wide open). At speed, an injector delivers less because of opening and closing time — that is what the duty cycle calculator is for.
E85 is a different liquid. The 10.5 factor is gasoline-only. Ethanol blends have a different density and, more importantly, need roughly 35% more volume for the same power — the size calculator handles that case.

Flow is only half the story

A partially clogged micro basket filter cuts real-world flow no matter what the math says. The Micro-Filter Basket Removal Tool, from $14.99, pulls the old ~6 mm basket filter straight out so a fresh one can go in — see the step-by-step removal guide. For a full service, the Universal EV1 Rebuild Kit, $72.49 covers 200 injectors with filters, seals and caps.

Free tracked USPS shipping in the US · 30-day returns · secure card checkout by Stripe · sold by Partsapiens.

Get the tool — from $14.99 Shop the 200-injector kit — $72.49

More injector calculators

Injector flow converter — cc/min ↔ lb/hr.
Injector size calculator — injector size for a target horsepower.
Max horsepower from your injectors — the reverse calculation.
Flow rate at a different fuel pressure — the square-root rule.
Injector duty cycle calculator — pulse width and RPM to duty %.
Fuel pump flow requirement — LPH your engine actually needs.

Last updated October 20, 2026 · Partsapiens, 5325 Alton Pkwy, Suite C300, Irvine, CA 92604 · partsapiens@gmail.com