Window & door sizing, egress, energy & cost calculators

Free, no-signup calculators for homeowners, DIYers and small contractors planning a window or exterior-door replacement — figure out what size a window is (united inches, square footage, rough opening), whether an opening meets egress code, how energy-efficient it is (U-factor, SHGC, ENERGY STAR), and what a job should cost. Every tool runs on the measurements you take and the prices you enter, and shows its formula, a worked example and a reference table.

Planning estimate: this is a planning estimate from the numbers you enter — not a bid or a contract. Window and door pricing depends on size, type, frame material, glass package, full-frame vs insert, trim, disposal, height/access and local labor. Get itemized written quotes from licensed, insured window/door installers before you commit.

Measure each opening and confirm sizes and clearances against the exact product you buy. Take three width and three height measurements and use the smallest of each; allow extra for custom sizes and waste. Sizes, clearances and rough-opening allowances vary by product and brand — read the spec sheet and the manufacturer’s data.

The window project, step by step

Size → quantity → egress & energy → cost → type & material → doors & planning — the whole journey in one focused hub.

1
Window Sizing & Quantity
Start here: united inches (width + height), glass square footage, rough-opening size with shim gaps, egress compliance (IRC R310), how many windows a home or room has, window-to-wall ratio, and standard vs custom size.
United-inches calculator Window area (square footage)Rough-opening calculator Egress window checker Window count calculator Window-to-wall ratio (WWR)Standard vs custom size
2
Window Cost Estimators
Budget the job: window replacement cost, installation cost, cost per window, whole-house cost, full-frame vs insert, cost by type and by frame material, and a contractor quote check — on the prices you enter from your own quotes.
Window replacement cost Window installation cost Cost per window Whole-house window cost Full-frame vs insert cost Window cost by type Window cost by frame material Window contractor quote check
3
Types, Frames & Glass
Compare and choose: double-hung vs casement vs sliding vs awning vs picture, vinyl vs wood vs fiberglass vs aluminum vs composite, single vs double vs triple pane, bay vs bow cost, low-E / gas-fill and a good/better/best tier reference.
Window type compare Frame material compare Single vs double vs triple pane Bay vs bow window cost Low-E / gas-fill reference Window brand tier reference
4
Energy Efficiency & Performance
Read the ratings: U-factor ↔ R-value, SHGC by climate goal, ENERGY STAR / IECC climate-zone checker, a fenestration energy-savings estimate, replacement payback, and a visible-transmittance / condensation reference.
U-factor ↔ R-value converter SHGC / solar-heat-gain reference ENERGY STAR climate-zone checker Window energy-savings estimator Replacement-window payback VT & condensation reference
5
Exterior Doors
The non-garage door adjacency: entry, patio / sliding, French and storm door cost, a pre-hung door rough-opening calculator, slab vs pre-hung, and a steel vs fiberglass vs wood material compare.
Entry door replacement cost Patio / sliding door cost French door cost Storm door cost Door rough-opening calculator Slab vs pre-hung reference Door material compare
6
Installation & Project Planning
Plan the work: window installation labor cost (by count, story and access), how to measure for replacement (smallest of three), trim / casing linear feet, a timeline & permit reference, and a disposal / lead-safe (pre-1978) reference.
Window installation labor cost How to measure for replacement Window trim / casing calculator Project timeline & permit reference Disposal / lead-safe reference

The ENERGY STAR / IECC climate-zone requirement reference

Our own neutral matrix: the LABELED ENERGY STAR 7.0 and IECC 2021 maximum window U-factor and SHGC by US climate zone, side by side, with the derived whole-window R-value from R = 1 ÷ U — one reference chart instead of a dozen single-brand spec sheets. It powers the ENERGY STAR climate-zone checker; see how it’s built in the methodology.

Open the climate-zone reference →

Built for the whole window & door project — and to stay correct forever

WindowCalcs gathers the calculations homeowners, DIYers and small contractors reach for when windows and exterior doors go in — what size a window is (united inches = width + height; glass area = width × height ÷ 144; the rough opening = unit size + shim gaps), whether a bedroom opening meets egress code, how energy-efficient a window is (U-factor, SHGC, R = 1 ÷ U, ENERGY STAR by climate zone), and what a window or door job costs — size → quantity → egress/energy → cost → type/material → doors, in one focused hub, in US units, without signup, with transparent formulas. Every tool shows not just the answer but the underlying formula, a worked example and a reference table, so you can sanity-check an installer’s quote.

Because the tools rest on timeless fenestration geometry and heat transfer (united inches = w + h; area = w × h ÷ 144; rough opening = size + shim gaps; R = 1 ÷ U; egress pass/fail against the labeled IRC R310 minimums; annual saving = area × ΔU × HDD × 24 ÷ 1000 ÷ efficiency × your energy price; payback = cost ÷ savings; cost = count × your $/window-or-door + labor + add-ons − discount, ×(1 + contingency)) and stable, labeled conventions (united-inches sizing, shim gaps, IRC R310 egress minimums, ENERGY STAR / IECC U-factor & SHGC, U/SHGC by frame × glazing, cost bands), they stay correct with no maintenance — no live material or labor price list, no regional cost index, no product catalog, no contractor directory. Cost tools use the prices you enter from your own quotes and bills; labeled cost bands are only a sanity guide. More at Sources & formulas, Methodology and About.

Estimates, not bids. Every result is a planning estimate from your own prices, or a sizing / quantity / egress-screening / energy guide — not a bid, an install procedure, or structural-header, whole-building heat-load, code or professional energy-audit advice. Get itemized written quotes from licensed, insured window/door installers; measure each opening (smallest of three) and confirm sizes, egress and energy ratings against the exact product and your local code and the NFRC label; and allow extra for custom sizes and waste.