Flow Rate & Velocity Calculator with Complete Pipe Specs
Calculate required GPM, velocities, and Reynolds numbers using actual pipe specifications. Select from stainless steel, carbon steel, CPVC, copper, and more.
Flow Rate & Velocity Calculators
Select your exact pipe specifications for accurate flow calculations based on actual internal diameters.
GPM → Velocity
Calculate velocity from flow rate with full pipe specifications
Velocity → Required GPM
Calculate flow rate needed to achieve target velocity
Reynolds Number Calculator
Verify turbulent flow conditions for effective cleaning
Pipe Size Advisor
Find all pipe sizes that achieve your target velocity
Disclaimer: These calculators are for reference purposes only. All values must be independently verified by qualified engineers. CXP Solutions assumes no liability for decisions or outcomes resulting from their use.
Complete Pipe Specifications
Internal diameter reference for all supported pipe materials and schedules. Click to expand each category.
Schedule 5S
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.710 |
| 3/4" | 0.920 |
| 1" | 1.185 |
| 1-1/2" | 1.770 |
| 2" | 2.245 |
| 3" | 3.334 |
| 4" | 4.334 |
| 6" | 6.407 |
Schedule 10S
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.674 |
| 3/4" | 0.884 |
| 1" | 1.097 |
| 1-1/2" | 1.682 |
| 2" | 2.157 |
| 3" | 3.260 |
| 4" | 4.260 |
| 6" | 6.357 |
| 8" | 8.329 |
Schedule 40
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.622 |
| 3/4" | 0.824 |
| 1" | 1.049 |
| 1-1/2" | 1.610 |
| 2" | 2.067 |
| 3" | 3.068 |
| 4" | 4.026 |
| 6" | 6.065 |
Schedule 80
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.546 |
| 3/4" | 0.742 |
| 1" | 0.957 |
| 1-1/2" | 1.500 |
| 2" | 1.939 |
| 3" | 2.900 |
| 4" | 3.826 |
Schedule 40 (STD)
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.622 |
| 1" | 1.049 |
| 1-1/2" | 1.610 |
| 2" | 2.067 |
| 3" | 3.068 |
| 4" | 4.026 |
| 6" | 6.065 |
Schedule 80 (XS)
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.546 |
| 1" | 0.957 |
| 2" | 1.939 |
| 3" | 2.900 |
| 4" | 3.826 |
Schedule 80
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.546 |
| 3/4" | 0.742 |
| 1" | 0.957 |
| 1-1/2" | 1.500 |
| 2" | 1.939 |
| 3" | 2.900 |
| 4" | 3.826 |
Schedule 40
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.622 |
| 1" | 1.049 |
| 1-1/2" | 1.610 |
| 2" | 2.067 |
| 3" | 3.068 |
| 4" | 4.026 |
Schedule 80
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.546 |
| 1" | 0.957 |
| 2" | 1.939 |
| 3" | 2.900 |
Type K (Heavy)
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.527 |
| 3/4" | 0.745 |
| 1" | 0.995 |
| 1-1/2" | 1.481 |
| 2" | 1.959 |
| 3" | 2.907 |
Type L (Medium)
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.545 |
| 3/4" | 0.785 |
| 1" | 1.025 |
| 1-1/2" | 1.505 |
| 2" | 1.985 |
| 3" | 2.945 |
Type M (Light)
| Nominal | ID (in) |
|---|---|
| 1/2" | 0.569 |
| 3/4" | 0.811 |
| 1" | 1.055 |
| 1-1/2" | 1.527 |
| 2" | 2.009 |
GPM Requirements for Schedule 10S Stainless
Target velocities for high-velocity flushing applications per ASME BPE guidelines.
| Pipe Size | ID (in) | 5 ft/sec | 6 ft/sec | 7 ft/sec | 8 ft/sec | 10 ft/sec |
|---|---|---|---|---|---|---|
| 1/2" | 0.674 | 6 | 7 | 8 | 9 | 11 |
| 3/4" | 0.884 | 10 | 12 | 13 | 15 | 19 |
| 1" | 1.097 | 15 | 18 | 21 | 24 | 29 |
| 1-1/2" | 1.682 | 35 | 41 | 48 | 55 | 69 |
| 2" | 2.157 | 57 | 68 | 80 | 91 | 114 |
| 3" | 3.260 | 130 | 156 | 182 | 208 | 260 |
| 4" | 4.260 | 222 | 266 | 310 | 355 | 443 |
| 6" | 6.357 | 494 | 593 | 692 | 790 | 988 |
| 8" | 8.329 | 848 | 1018 | 1187 | 1357 | 1696 |
Formula: GPM = (Velocity × ID²) / 0.4085 | Values rounded to nearest whole number
Industry standard for pharmaceutical and biotech high-velocity flushing per ASME BPE and ISPE guidelines.
Velocity Guidelines
Understanding flow velocity requirements for different applications.
Particles settle in low points. Biofilm and debris accumulation likely. Not suitable for cleaning applications.
Transitional flow regime. May achieve some particle transport but insufficient for reliable debris removal.
Industry standard for HV flushing. Fully turbulent flow ensures particle suspension and effective system cleaning.
Effective cleaning but evaluate erosion risk on soft materials. Verify pressure ratings and check gasket integrity.
Understanding Reynolds Number
The Reynolds number (Re) is a dimensionless quantity that predicts flow patterns. For effective high-velocity flushing and CIP operations, turbulent flow is essential for particle suspension and removal.
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