A/B variant · Now in beta

Plan your solar system in 60 seconds — for free.

Know the right solar system, likely cost, payback, and verified installers before you pay for solar.

No credit card Free forever calculator PRD §10 deterministic engine
Rooftop solar PV array against a clear sky
5.2 kWp PV 14 × 380W panels
$ 7.3 yr payback $8,420 installed
82/100 confidence High — site survey still required
< 60s
to your first estimate
3 tiers
Budget · Standard · Premium
$0
free forever calculator
16 sections
downloadable PDF (PRD §13)

SolarSizer Plans

Free to design. Pay only to download.

Size your system, compare all three tiers and read your confidence score at no cost. Choose a plan only when you want the report — or, as an installer, the leads.

See full pricing

Free Design

$0forever

Everything you need to size a system and decide whether solar is worth it for your roof. No card required.

Start free estimate

Includes:

  • Design & generate your solar PV system
  • Budget · Standard · Premium tiers side-by-side
  • Confidence score with formula disclosure
  • Bill upload with OCR extraction
  • Compare scenarios on your dashboard

Detailed Report

$9one-time

Unlock the downloadable 16-section PDF, version-stamped so it stays reproducible. Or go unlimited at $23/month.

Compare report plans

Includes:

  • Everything in Free Design
  • Downloadable 16-section PDF (PRD §13)
  • Version-stamped for reproducibility
  • Lifetime access from your account
  • Share link for your installer or bank

Installer Pro

$49/ month

Verified, lead-quality-scored homeowner projects delivered to your inbox — with a first-month money-back guarantee.

Register as installer

Includes:

  • Lead-quality scored homeowner inquiries
  • Verified phone & email contact details
  • Lifecycle tracking, new → converted
  • Country / region targeting
  • First-month money-back guarantee

System Tiers

Same demand, three levels of hardware

Budget System

Ground-mounted solar panels on grass

350 Wpanels

Value-class modules with lead-acid storage. This is the cost baseline every other tier is capped against.

Size it free

Standard System

Rows of solar panels under a blue sky

450 Wpanels

Lithium storage and better inverters, with the installed total capped at 1.25× your Budget build.

Size it free

Premium System

Large rooftop solar array at sunset

550 Wpanels

Top-class modules and lithium storage for the most output per m² of roof — capped at 1.5× your Budget build.

Size it free
How it works

From appliance list to installer quote in under a minute

A deterministic engine sizes the system. A confidence score tells you how much to trust the numbers. You decide what to do next.

1

Tell us your loads

List your main appliances or upload an electricity bill — we extract usage automatically with OCR.

2

See three sized systems

Budget, Standard, and Premium tiers with PV / inverter / battery / cost / payback side-by-side.

3

Request quotes or download

Send your project to up to 3 verified installers, or download a 16-section PDF you can share.

What you get

Everything you need to make a confident solar decision

No upsell to see results, no fake precision. Every number you see is reproducible from a stamped formula version + assumption set.

Deterministic sizing engine

PRD §10 formulas: PV kWp, inverter kW, battery kWh, panel area, peak load, payback. Same answer every time.

Transparent confidence score

0–100 score with the seven PRD §11 weighted factors. You see exactly which inputs lifted or capped your number.

Bill OCR with reconciliation

Upload your bill, we extract kWh + tariff. Bill-vs-appliance diff flags loads you've forgotten.

Three tiers, one demand

Budget · Standard · Premium use the same kWh demand but different component classes — installer margin is broken out, not hidden.

Verified installer marketplace

Lead-quality score (PRD §8.9 FR-045) helps installers prioritise. You choose who sees your contact details.

Reproducible PDF report

16 PRD §13 sections. Every report stamps formula + assumption + price-table version so old reports never go stale.

Why SolarSizer

Get a real estimate before you ever talk to an installer

Traditional solar shopping starts with a 3-quote scramble. We flip that: get a credible number first, then compare quotes against a benchmark.

Traditional installer journey

  • 2–4 weeks of site visits before any number
  • No way to compare quotes apples-to-apples
  • System size, tariff, payback all opaque
  • Bill data interpreted differently by each installer
  • Hidden margin baked into every line item

SolarSizer AI

  • First credible estimate in under 60 seconds
  • Three tiers side-by-side from one demand
  • Every number traces back to a formula + assumption
  • Confidence score tells you what to trust
  • Installer margin broken out as its own line item
Pricing

Free to use. Pay only for the downloadable report.

Calculator, confidence score, scenario comparison, installer quote requests — all free. The detailed PDF is $9 one-time, with lifetime access from your account.

Stop guessing. Get a credible solar estimate in 60 seconds.

No site visit required. No credit card. Just a few questions and three sized systems ready for installer quotes.