🚪 Windows & Doors

Windows & Doors calculators

Window area, sill, rough opening, glass weight and replacement, sliding/bifold door, curtain and blind sizing, plus glazing energy savings.

Curtain / Blind Size Calculator

Calculates curtain fabric or blind dimensions from window size
Door Rough Opening Calculator

Calculates rough opening dimensions for door installation
Flyscreen Calculator

Calculates the flyscreen mesh area needed from your window and door opening sizes
Glass Weight Calculator

Estimates weight of a glass pane by dimensions and glass type
Window Glazing Cost Estimator

Build a costed schedule for a set of windows
Heat Loss Through Glazing Calculator

Watts and annual kWh lost through glass
Glazing Panel Calculator

Calculates glazing panel area and weight for conservatories
Rooflight & Skylight Daylight Area Calculator

Recommended rooflight area for good daylight
Sliding / Bifold Door Calculator

Estimates panel count and structural header for wide openings
Trickle Vent Area Calculator

Required background ventilation area for a room
U-Value Contribution Calculator

Area-weighted U-value of glazing plus wall
Window Area Calculator

Calculates total window area for heat loss and glazing sizing
Window Energy Rating (WERS) Calculator

Estimates window energy rating (A to G) from U-value and solar gain
Window Replacement Cost Calculator

Estimates cost to replace windows by count, size, and glazing type
Window Sill Calculator

Calculates linear metres or feet of window sill board
Window-to-Wall Ratio Calculator

Work out the glazed fraction of a wall