Solar Tax Credit Calculator

Estimate your federal Section 25D residential solar tax credit, your state credit, and how much of it your tax bill actually lets you claim this year.

“Placed in service” means the date your system was installed and ready to use, not the date you signed or paid. Section 25D was terminated for systems placed in service after December 31, 2025, so a 2026 install earns no federal credit. Your tax liability is the total federal income tax you owe for the year, before withholding — line 22 of Form 1040 is the usual starting point, not the refund or the amount still due.

Utility rebate

A rebate paid by your utility is generally treated as a reduction in what you paid, so it comes off the cost before the federal credit is calculated — a $25,000 system with a $1,000 utility rebate earns 30% of $24,000, not of $25,000. State tax credits work differently and do not reduce the federal basis, which is why this calculator stacks them on the full cost.

By · Energy analysts and engineers documenting every formula, source, and limitation behind our calculators.

Published Formula, sources & limitations

Share this calculatorFree to use and free to embed — no sign-up and no attribution required.

Share Solar Tax Credit Calculator

Page link

Share to

Embed on your site

Paste this iframe into any page, blog post, or app. It renders the calculator on its own, with no header or footer.

<iframe src="https://solarcalculator4u.com/embed/solar-tax-credit-calculator/" title="Solar Tax Credit Calculator" width="100%" height="820" style="border:0;max-width:720px" loading="lazy"></iframe>
HOW IT WORKS

How does the solar tax credit calculator work?

The calculator applies the 30% Section 25D residential credit to your eligible cost, checks it against the tax liability you can actually offset this year, and stacks any state credit and utility rebate on top to reach a net cost.

1

Enter cost & date

Give your total system cost and whether it was placed in service on or before December 31, 2025.

2

Add state & liability

Pick your state for its credit, and enter the federal tax you owe for the claim year.

3

See what you can claim

Get the federal credit, how much is usable this year, what carries forward, and your net cost.

The date is the first thing that matters

Most solar tax credit calculators online still assume a flat 30% for everyone. That has not been true since the end of 2025. The One Big Beautiful Bill Act terminated the Section 25D residential credit for property placed in service after December 31, 2025, so the single input that decides whether you get anything at all is a date — not your income, not your system size.

Placed in service means installed and ready to use, which in practice usually tracks final inspection or permission to operate rather than the day you signed. If your project straddled the end of 2025, that documentation is worth locating before you file.

THE CALCULATIONFederal credit = (cost − utility rebate) × 30%, if placed in service on or before Dec 31, 2025

Usable this year = min(credit, tax liability). Carryforward = credit − usable. Net cost = cost − (federal credit + state credit + utility rebate).

Worked example: a 2025 install with liability to spare

EXAMPLE 1

$25,000 system, placed in service November 2025, $9,000 federal tax liability, no state credit

A homeowner completes a $25,000 system in November 2025 and receives permission to operate in December, comfortably inside the cut-off. Their total federal income tax for 2025 is $9,000.

  1. Federal credit: $25,000 × 30% = $7,500.
  2. Usable in the claim year: the $9,000 liability exceeds the credit, so all $7,500 applies.
  3. Carried forward: $0.
  4. Net cost: $25,000 − $7,500 = $17,500.

Result: the full $7,500 credit lands in one year, for a 30% effective discount.

Worked example: the credit outruns the tax bill

EXAMPLE 2

$32,000 system, placed in service 2025, $4,000 federal tax liability, $1,000 utility rebate

A larger system on a lower tax bill is where the nonrefundable nature of the credit starts to bite. The utility also paid a $1,000 rebate, which reduces the cost the federal credit is figured on.

  1. Federal basis: $32,000 − $1,000 utility rebate = $31,000.
  2. Federal credit: $31,000 × 30% = $9,300.
  3. Usable in the claim year: capped by the $4,000 liability, so $4,000 applies.
  4. Carried forward: $9,300 − $4,000 = $5,300, available against future years' tax.
  5. Net cost: $32,000 − ($9,300 + $1,000) = $21,700.

Result: a $9,300 credit on paper, but only $4,000 of it reduces this year's tax — the rest waits.

Understanding each result

Federal credit (25D) is 30% of eligible cost after any utility rebate, with no dollar cap for solar electric property. It shows as $0 for systems placed in service in 2026 or later.

State credit comes from our state table, which carries only statewide residential programs verified against DSIRE. A $0 here does not mean nothing is available — utility and municipal programs are not in the table.

Federal credit usable this year is the credit capped by your tax liability, because Section 25D is nonrefundable. Carried forward is the remainder, which reduces tax in future years rather than being lost.

Net cost and effective discount combine every incentive against your gross cost, so systems of different sizes can be compared on equal footing.

What this calculator doesn't model

This is a planning estimate, not tax advice. It does not know your filing status, your other credits, alternative minimum tax exposure, whether your state taxes the value of a rebate, or how many future years it would take to absorb a large carryforward. It also does not model leases and power purchase agreements, where the provider owns the system and claims the commercial credit instead of you. Confirm eligibility, your placed-in-service date, and the treatment of any rebate with a qualified tax professional before filing.

Common ways to use this calculator

Checking a 2025 install

Confirm what the credit is worth and how much of it your tax liability lets you claim.

Planning a 2026 purchase

See the honest post-credit numbers before an installer quotes you a “30% off” price that no longer exists.

Sizing a carryforward

Work out how much of a large credit spills into future tax years.

Comparing state programs

Switch states to see how much a statewide credit changes the net cost.

Privacy and appropriate use

Your inputs are processed directly in your browser and are not sent to a database. This is a planning-stage estimate, not tax, legal, or financial advice — confirm credit eligibility and treatment with a qualified tax professional before making filing decisions.

Calculate my tax credit ↑Commercial solar? Use the ITC calculator →
FREQUENTLY ASKED QUESTIONS

Questions about the solar tax credit calculator.

Clear answers about eligibility, the 2025 cut-off, carryforward, and how state and utility incentives interact.

Is there still a 30% federal solar tax credit in 2026?

Not for homeowners buying their own system. The Residential Clean Energy Credit under Section 25D was terminated for property placed in service after December 31, 2025, so a cash or loan purchase completed in 2026 earns no federal credit. The credit is still relevant if your system was placed in service on or before that date and you are filing or amending a return that covers it. Businesses and third-party owners such as lease and power purchase agreement providers claim the separate Section 48E credit instead, which is why some leases still advertise a credit.

What does 'placed in service' actually mean?

It means the date the system was installed and ready for use — not the date you signed the contract, made a deposit, or paid the final invoice. For most residential solar this is when installation is complete and the system is capable of generating, which in practice is usually tied to passing final inspection or receiving permission to operate from the utility. If your install straddled the end of 2025, this date is what decides whether you get the credit at all, so confirm it with your installer and keep the documentation.

How much is the residential solar tax credit worth?

For systems that qualify, it is 30% of eligible cost with no dollar cap for solar electric property. Eligible cost includes the panels, inverters, mounting equipment, wiring, labor for onsite preparation and installation, and permitting fees. A $25,000 system therefore generates a $7,500 credit. Battery storage of at least 3 kWh installed with the system also qualifies at the same rate.

Is the solar tax credit refundable?

No. Section 25D is nonrefundable, which means it can reduce your federal income tax to zero but will not pay out the remainder as a refund. If your credit is larger than your tax liability for the year, the excess is not lost — it carries forward to reduce tax in future years. This is why the calculator asks for your tax liability separately from your system cost: the credit's headline value and the amount you can actually use in one year are often different numbers.

What tax liability figure should I enter?

Use your total federal income tax for the year, before subtracting what your employer already withheld. On Form 1040 that is the total tax line, not your refund and not the balance you still owe at filing. A common mistake is entering the amount due with the return, which is usually much smaller than total liability and makes the credit look far less usable than it is. If you had $6,000 of federal income tax for the year and $5,500 was withheld from your paychecks, the figure to enter is $6,000.

Do state credits and utility rebates change the federal calculation?

They are treated differently. A rebate from your utility is generally considered a reduction in the purchase price, so it comes off the cost before the federal credit is figured — a $25,000 system with a $1,000 utility rebate earns 30% of $24,000. A state tax credit generally does not reduce your federal basis, so the federal credit is still calculated on the full cost and the state credit stacks on top. This calculator follows that treatment, which is why the utility rebate sits in its own section.

Which states have their own solar tax credit?

Only a handful maintain a statewide residential credit, and the amounts and caps vary widely — the state selector here covers the programs in our table, each verified against the DSIRE database. Many more incentives exist at the utility and municipal level, including upfront rebates, performance payments, and property or sales tax exemptions, and those are not captured by a statewide table. Check your specific utility as well as your state before assuming there is nothing available.

Can I claim the credit on a rental property or a second home?

Rules differ by property type. Section 25D applies to a residence you live in, and second homes you use personally can qualify for solar electric property, but a property you rent out to others does not qualify under 25D. Landlords and businesses fall under the separate commercial credit instead — see our Solar Investment Tax Credit Calculator for that treatment. Mixed-use situations, such as a home office or a partially rented property, have their own apportionment rules worth checking with a tax professional.

Is this tax advice?

No. This is a planning estimate that applies published credit rates to figures you enter, and it does not know your filing status, your other credits, alternative minimum tax exposure, or how your state treats solar incentives. Credit eligibility, the placed-in-service date, and the treatment of any rebate should be confirmed with a qualified tax professional before you file.

Is my data stored?

No. All inputs and calculations run directly in your browser and are not sent to a server or saved in an account. General site usage may be measured through Google Analytics as described in our Privacy Policy.