Groundworks & civils calculator
Calculate pipe falls and gradients for drainage runs - a fall profile diagram shows the run stepping down to scale from manhole to manhole, and a level schedule does the setting-out maths for you.
The Runs tab's run list and fall profile diagram, the Levels tab's level schedule, and the Guide tab's minimum fall reference - all shown in dark mode.
Runs tab - run list and fall profile (dark mode)
Levels tab - level schedule (dark mode)
Guide tab - minimum fall reference (dark mode)
A longitudinal fall profile diagram chains every run end to end by cumulative chainage and invert level, stepping downward to scale - a genuine picture of the run, not just a table of numbers.
Add a run for each length of pipe - each one's start level is automatically the previous run's end level, chained from a single start invert level you set.
Chainage, start level, end level and fall for every run, laid out as a setting-out schedule - ready to check against a drainage layout drawing or hand to groundworkers.
Each run is checked against a minimum self-cleansing fall for its pipe diameter and drainage type - runs flatter than recommended are flagged right away, on the run list and on the profile diagram itself.
Three pipe diameters, each with its own minimum fall for foul and for surface water drainage - switch per run, no lookup table required.
Copy a plain-text summary or export it as a standalone HTML file. Light/dark theme remembers your choice, and rotating sample runs let you explore the app.
MicroDrainage (Innovyze, an Autodesk company) is the well-known industry-standard software for detailed drainage and SuDS network design used by civil engineers - here's how a focused, one-off contractor fall-check tool compares.
| Feature | Drainage Fall Calculator | MicroDrainage |
|---|---|---|
| Pricing model | One-off purchase after a free trial | Enterprise subscription, custom quote (rated high-cost by reviewers) |
| Works fully offline | ✓ | ~ |
| Instant standalone fall/level sense-check | ✓ | ✕ |
| Full hydraulic network modelling & SuDS compliance reporting | ✕ | ✓ |
| CAD (Civil 3D) integration | ✕ | ✓ |
| Minimum-fall check flagged automatically in minutes | ✓ | ~ |
| Built for site managers/contractors rather than drainage engineers | ✓ | ✕ |
| Requires specialist training | ✕ | ✓ |
Comparison based on Innovyze/Autodesk's publicly listed product information as of August 2026 (innovyze.com, g2.com, alumascwms.co.uk) - features and availability change over time, so check innovyze.com for current details. MicroDrainage is a trademark of its respective owner; this comparison is for informational purposes and isn't sponsored by or affiliated with Innovyze or Autodesk.
Drainage Fall Calculator is a Windows desktop app, free to try from the Microsoft Store.
Yes - Drainage Fall Calculator uses the same shared Metre2 account as Vector, Forma and every other Keystone app. Sign in once and it works everywhere.
Each run's start invert level is the previous run's end level, chained from a single start level you set - the same way a drainage run is set out on site from manhole to manhole.
Approximate self-cleansing minimum fall figures by pipe diameter and drainage type (foul or surface water), broadly following UK Building Regulations Approved Document H guidance. It's a design aid, not a substitute for your drainage engineer's design - always confirm against the current regulations.