Enter your battery’s usable capacity to estimate the federal Cheaper Home Batteries discount at today’s rules (STC factor 6.8 from1 May 2026). State schemes appear below the federal result for stacking context — we display them; we don’t invent a combined total, because eligibility varies.

JavaScript needed for the interactive tool

The live calculator needs JavaScript. The worked examples below use the same formula and current data file values.

Usable battery capacity (kWh)

State

Installed cost before rebates ($)

Advanced: STC price

STC price assumed ($)

Households typically receive slightly less than headline after admin costs. Headline ≈ $40.

Federal rebate

—

STCs: —
Share of cost: —
Net cost: —

0142850 kWh

0–14 kWh: 100% of STC factor
14–28 kWh: 60% of STC factor
28–50 kWh: 15% of STC factor

State schemes (displayed, not summed)

Stacking depends on eligibility. Treat these as leads to verify — not a guaranteed extra discount.

How the maths works

Eligible usable capacity is capped at 50 kWh. For each tier band, we take the width of your capacity inside that band, multiply by the STC factor (6.8), multiply by the band’s percentage, then sum. STCs are whole certificates only (floor), then multiplied by your assumed STC price.

Static worked examples at current data-file rates
System	Calculation sketch	STCs	Rebate @ $37
10 kWh battery	10 × 6.8 (tiered)	68	$2,516
13.5 kWh battery (Powerwall 3 class)	13.5 × 6.8 (tiered)	91	$3,367
30 kWh large system	30 × 6.8 (tiered)	154	$5,698

More context on the federal battery rebate hub andwhat changed in May 2026.