CalcTrap and Drain Calculator
Last updated: 2026-08-24
Trap and Drain Calculator — Plumbing trap and drain sizing based on fixtures and pipe diameter.
Inputs
Result
Enter values and press Calculate
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How to use it
- Calculate sifones: 5 aparatos = 5 sifones (1 per aparato)
- Calculate pipe with slope: 8m × 1.02 = 8.16m (ligeramente more per inclination)
- Verify slope: 2% = 2cm per meter = 16cm in 8m
- Diámetros: lavabo 40mm, ducha 50mm, inodoro 110mm
Common mistakes
- ⚠️ Not instalar trap in each aparato (entran olores)
- ⚠️ Pendiente insuficiente (less of 2% causa obstrucciones)
- ⚠️ Not prever ventilación of bajante (puede hacer sifonaje)
Worked example
Calculate traps and drains for 5 sanitary fixtures with 110mm downpipe.
To {num_aparatos} aparatos with bajante of {length_bajante_m}m need {sifones_ud} sifones, {sumideros_ud} sumideros and {tuberia_m}m of pipe with {slope_pct}% of slope.
Input guide
| Field | Typical range |
|---|---|
| longitud_bajante_m | length from aparato más alejado to bajante principal |
| pendiente_pct | Saneamiento: 2-3% minimum for evitar obstrucciones |
| num_aparatos | Lavabos, inodoros, duchas, bidets, lavadoras |