Free Resources / Sqratch Tools
THE STUDIO MATH, DONE.
22 free calculators for the numbers every project starts with. No sign-up, no spreadsheet, no guessing.
Site & Planning
Area Unit Converter
Convert between sq ft, sq m, sq yd (gaj), acres, hectares, guntha, cents and grounds — instantly and exactly.
Open tool →FSI / FAR Calculator
Plot area × FSI = permissible built-up area, with premium FSI and TDR as separate inputs. Works in both directions.
Open tool →Ramp Gradient Calculator
Rise, run, gradient (1:x), percentage and degrees — plus the ramp length you need to hit a target gradient.
Open tool →Setback & Ground Coverage Calculator
Plot dimensions + setbacks on all four sides → buildable footprint and ground coverage percentage.
Open tool →Drawing Scale Converter
Convert paper ↔ real-world dimensions at any scale, and find the scale that fits your site on an ISO sheet.
Open tool →Solar Shading Angle
Calculate the required overhang depth for shading a window based on sun altitude angles.
Open tool →Parking Lot Capacity
Estimate the number of parking spaces possible on a site using standard Equivalent Car Space (ECS) metrics.
Open tool →Structural & Shell
Staircase Calculator
Floor-to-floor height → equal risers, treads and total run, with Blondel's 2R+T comfort check.
Open tool →Concrete Slab & Footing Calculator
Estimate the total volume of concrete for slabs or footings, and convert it instantly into standard pre-mix bags.
Open tool →Brick & Mortar Estimator
Calculate the exact number of bricks and volume of mortar required for a given wall area based on standard regional brick sizes.
Open tool →Roof Pitch & Rafter Calculator
Convert roof pitch to degrees/percentage, and calculate the exact rafter length needed for your span and overhang.
Open tool →Wood Joist Span Checker
Compare your span against published SPF No.2 reference span tables for wooden floor joists. Reference only, not a code-compliance check.
Open tool →Finishes & Hardscape
Tile Estimator
Calculate the exact number of tiles needed for your floor or wall area, including grout joint spacing and wastage.
Open tool →Paint Estimator
Estimate the exact volume of paint required in Liters and Gallons based on your surface area and number of coats.
Open tool →Drywall & Plasterboard Estimator
Calculate the number of drywall sheets and screws needed to cover your framing area.
Open tool →Paver & Hardscape Estimator
Estimate the number of paving stones and the volume of bedding sand required for your hardscape project.
Open tool →Room Acoustics (RT60)
Estimate the reverberation time of a room using Sabin's formula and average absorption coefficients.
Open tool →MEP Systems
AC Tonnage Estimator
Estimate the required Air Conditioning tonnage and BTUs based on room volume and sun exposure.
Open tool →Air Changes Per Hour (ACH)
Calculate the ACH rate for ventilation systems based on room volume and fan CFM.
Open tool →Water Tank Volume
Calculate the exact capacity of cylindrical water tanks in Liters and Gallons.
Open tool →Pipe Volume & Flow
Calculate the internal liquid capacity of a pipe based on its inner diameter and length.
Open tool →Rainwater Harvesting
Estimate rainwater harvesting capacity based on catchment area, rainfall, and surface runoff coefficients.
Open tool →Standards & Library
Universal Design Library
Quick-reference values for accessible architecture: ramp gradients, wheelchair clearances, washroom dimensions. Rounded reference figures with the codes to verify against.
How These Are Built
Every tool runs on definitional math and published standards only — exact unit definitions, ISO 216 sheet sizes, plain geometry. Where a value depends on your city (FSI, setbacks, riser limits), we make it an input and tell you where to find it, instead of baking in a number that could be stale. Each tool states its basis and assumptions on the page.