Set accurate slopes for slabs and toppings. Switch between imperial and metric units instantly today. Compare against targets before pouring, screeding, or leveling work.
| Scenario | Rise | Run | Slope (in/ft) | Slope (mm/m) | Slope (%) |
|---|---|---|---|---|---|
| Garage to door | 0.75 in | 12 ft | 0.0625 | 5.21 | 0.521 |
| Shower pan | 20 mm | 1.2 m | 0.2000 | 16.67 | 1.667 |
| Balcony drainage | 1.5 in | 10 ft | 0.1500 | 12.50 | 1.250 |
Floor slope controls where water and wash down fluids travel. In service bays, balconies, and wet rooms, a small gradient reduces ponding that can damage finishes, create slip hazards, and increase maintenance. The calculator converts field measurements into comparable metrics so you can confirm that design intent is met across long runs. It also helps teams document acceptance checks during inspections and handover. Record results in daily quality reports.
Crews often measure in inches over feet, while drawings may specify millimeters per meter or percent. Converting by hand can introduce rounding drift, especially when tolerances are tight. This tool normalizes all inputs to millimeters, then reports in/ft, mm/m, percent, and degrees so checks remain consistent from layout to pour. Use the same decimal precision for repeated checkpoints on a slab grid.
Use Rise + Run for direct tape and level readings. Use Start/End Elevations when you have survey shots or laser levels. Use Start/End Thickness when a topping, screed, or mortar bed changes depth. Each method produces the same slope ratio, making it easier to reconcile different sources of measurement. Confirm that your run is horizontal, not the sloped surface length.
Percent slope is convenient for specifications, while in/ft helps on small interior spans. The angle value is useful when verifying slope with digital inclinometers. The “1 in X” output communicates gradient clearly for stakeholders. Direction indicates whether the surface rises or falls relative to your reference point. Pair results with spot elevation notes to track corrective grinding or patching.
Typical uses include garage ramps, slab-on-grade drainage to door thresholds, shower pans to drains, exterior plaza decks, and mechanical room housekeeping pads. For coordination, the optional design helper estimates required rise over a target length, supporting quick checks before screeding, grinding, or correcting low spots. It is equally useful for verifying flatwork that must shed water without affecting accessibility transitions.
It is inches of vertical change for every foot of horizontal distance. It is convenient for short runs, layout marks, and quick checks with a tape and level.
It is millimeters of rise or fall over one meter of horizontal run. Many specifications use mm/m because it scales cleanly across long spans and metric grids.
Use Rise + Run for direct measurements, Elevations for survey or laser shots, and Thickness for toppings or screeds. All methods output the same slope ratio.
A negative value means the end point is lower than the start point based on your inputs. The direction label helps you confirm whether you entered start and end points correctly.
Accuracy depends on your measurements. Use consistent units, keep the run horizontal, and measure rise with reliable levels. The tool simply converts and formats the underlying ratio.
It estimates the required rise over a chosen length for a target slope in mm/m, in/ft, percent, or 1 in X. It is helpful for pre-pour planning and corrective work.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.