Free tools

55 free tools for the property trades.

The working maths of surveying, decorating, building, fire safety, CCTV and lettings - free, instant, no sign-up. The same tools ship inside the RoomPlot app, where the measurements come straight from a room scan.

Converters & essentials

Length Converter mm, cm, m, inches, feet-and-inches and yards in one place. Area Converter Square metres, square feet, square yards, acres and hectares. Plan Scale Converter Turn drawing measurements into real sizes at any scale. Slope & Gradient Calculator Rise and run to percent, degrees and 1:x ratio.

File viewers

DXF Viewer Open and read DXF CAD drawings in your browser - no software. USDZ Viewer Inspect a USDZ 3D file and view it in AR on iPhone or iPad.

Property & rentals

Price per Square Metre / Foot Compare listings by price per m² and per sq ft. Rental Yield Calculator Gross and net yield from price and monthly rent. Mortgage Payment Calculator Monthly repayment and total interest for any loan. Room Area Adder Add room sizes together into a total floor area. Estate Agent Commission Calculator Fee from sale price, rate and your VAT rate. Tenant Affordability Calculator The income a tenant needs for a given rent - any market's rule. Mortgage Overpayment Calculator Interest saved and years cut by paying extra monthly. Flip / Renovation Profit Calculator Purchase, refurb and fees against resale - profit and ROI.

Surveying & site

Diagonal / Square Check Is it square? Expected diagonal from two sides. Triangle Area Calculator Area from three sides - Heron's formula. Room Volume Calculator Length x width x height in m³, cubic feet and litres. Drainage Slope Calculator Pipe run to fall, gradient ratio and percent. Accessibility Ramp Calculator Step height to ramp length per ADA / UK Part M.

Fire safety

Smoke & Heat Detector Coverage Floor area to the number of detectors (BS 5839-1). Detector Spacing Check Test detector grid spacing against BS 5839-1 limits. Fire Alarm Battery Calculator Standby battery Ah for a panel per BS 5839-1. Cable Voltage Drop Calculator Loop voltage drop on 12/24 V device circuits. Alarm Sound Level Calculator Sounder dB(A) heard at a distance vs BS 5839 targets. Fire Extinguisher Calculator Extinguishers needed for a floor area (BS 5306-8).

Security & CCTV

CCTV Lens & Field of View Focal length to scene width at any distance. CCTV Pixel Density (DORI) Pixels per metre and what the image can prove. CCTV Storage Calculator Cameras, bitrate and retention days to drive size. CCTV Network Bandwidth Will the uplink carry all the cameras? PoE Budget Calculator Device load vs switch PoE budget, with port class.

Decorating & interiors

Paint Calculator Room size to litres of paint and tins to buy. Wallpaper Calculator Walls and pattern repeat to rolls to buy. Tile Calculator Area and tile size to tiles to buy, with wastage. Flooring Calculator Floor area to packs or boxes to buy. Will It Fit? Furniture Checker Will the sofa pass the doorway? Exact geometry. Lighting / Lumens Calculator Room size to lumens and how many bulbs. TV Size & Distance Calculator Sofa distance to the right screen size. Curtain Fabric Calculator Track width and drop to fabric metres.

Build & renovate

Concrete Calculator Slab size to cubic metres, bags and tonnes. Brick & Block Calculator Wall area to bricks or blocks plus mortar. Drywall / Plasterboard Calculator Wall area to boards, with wastage. Stud Wall Calculator Studs at 400/600 centres plus timber length. Skirting / Baseboard Calculator Room perimeter to lengths to buy. Radiator BTU Calculator Room size to heat output in BTU and watts. Stair Calculator Floor height to risers, going and total run. Roof Pitch Calculator Rise and run to degrees, x:12 and rafter length. Excavation & Soil Calculator Dig volume, soil bulking, weight and skip loads. Gravel & Aggregate Calculator Area and depth to tonnes, bulk bags and small bags. Plaster Coverage Calculator Wall area to 25 kg bags for skim or undercoat.

Property management

Prorated Rent Calculator Mid-month move-in to the exact partial rent. Bill Split by Area Share a bill across units by floor area. Energy Cost Calculator Appliance wattage to kWh and running cost. Room Occupancy Calculator Is the bedroom legally big enough? England HMO minima. Ventilation Fan Calculator Room size to extract fan airflow - m³/h, L/s, CFM. Dew Point & Condensation Risk Dew point from temperature and humidity, plus mould risk.