Solar Investment Tax Credit Calculator

Estimate your Section 48E ITC, MACRS depreciation tax shield, and net cost for a U.S. commercial or business solar project.

Section 48E's base commercial rate is 30% with prevailing wage and apprenticeship requirements met (6% without). Stack up to 70% by adding 10% for domestic content, 10% for an energy community site, and 10–20% for a low-income community or Tribal land bonus.

Depreciation assumptions

The IRS requires reducing your depreciable basis by half of whatever ITC you claim (cost − 50% × ITC value). This calculator applies your blended tax rate to that full basis as a simplified stand-in for 5-year MACRS accelerated depreciation, which front-loads most of the deduction into the first year or two under current bonus-depreciation rules. A 21% federal rate alone, or 21–28% blended with a state corporate rate, are common starting points — confirm your actual bracket with a tax advisor.

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HOW IT WORKS

How does the solar ITC calculator work?

The calculator stacks three sources of value — the Section 48E investment tax credit, a MACRS depreciation tax shield, and any state or utility cash incentive — against your gross system cost to estimate a net cost and effective discount.

1

Enter cost & ITC rate

Set your gross system cost and the Section 48E rate you expect to claim, including any bonus adders.

2

Add cash incentives

Include any state, utility, or grant-based cash incentive your project qualifies for.

3

View your net cost

See the ITC value, depreciation tax shield, total incentive, and effective discount off gross cost.

Three incentives, stacked in a specific order

Commercial solar economics in the U.S. typically combine three separate benefits, and the order they're calculated in matters. The ITC value comes first — a direct percentage of gross cost. That credit then triggers a basis reduction: IRS rules require cutting the property's depreciable basis by half the ITC claimed before computing depreciation. The depreciation tax shield is calculated on what's left of that reduced basis. Finally, any cash incentive — a state rebate, utility payment, or grant — adds on top as a straightforward dollar reduction, without affecting the ITC or depreciation math.

THE CALCULATIONNet cost = gross cost − (ITC value + depreciation shield + cash incentive)

ITC value = cost × ITC %. Depreciable basis = cost − 50% × ITC value. Depreciation shield = basis × blended tax rate.

Worked example: a straightforward base-rate commercial project

EXAMPLE 1

$250,000 system, 30% base ITC, no state cash incentive, 21% blended tax rate

Say a business installs a $250,000 rooftop system, qualifies for the 30% base Section 48E rate by meeting prevailing wage and apprenticeship requirements, has no state cash incentive available, and uses the flat 21% federal corporate rate with no state income tax.

  1. ITC value: $250,000 × 30% = $75,000.
  2. Depreciable basis: $250,000 − (50% × $75,000) = $250,000 − $37,500 = $212,500.
  3. Depreciation tax shield: $212,500 × 21% = $44,625.
  4. Total incentive: $75,000 + $44,625 + $0 = $119,625.
  5. Net cost: $250,000 − $119,625 = $130,375.

Result: about $130,375 net cost, a $119,625 total incentive, and a 47.9% effective discount off gross cost.

Worked example: stacked bonus adders with a state grant

EXAMPLE 2

$600,000 system, 50% stacked ITC, $40,000 state grant, 26% blended tax rate

Now suppose a larger $600,000 project qualifies for the 30% base rate plus a 10% domestic content adder and a 10% energy community adder, for a 50% total ITC. The business also receives a $40,000 state grant, and operates in a state with corporate income tax, giving a 26% blended federal-plus-state rate.

  1. ITC value: $600,000 × 50% = $300,000.
  2. Depreciable basis: $600,000 − (50% × $300,000) = $600,000 − $150,000 = $450,000.
  3. Depreciation tax shield: $450,000 × 26% = $117,000.
  4. Total incentive: $300,000 + $117,000 + $40,000 = $457,000.
  5. Net cost: $600,000 − $457,000 = $143,000.

Result: about $143,000 net cost, a $457,000 total incentive, and a 76.2% effective discount off gross cost.

Understanding each result

ITC value is the direct federal tax credit, calculated as a straight percentage of gross system cost.

Depreciation tax shield estimates the value of writing off the depreciable basis against taxable income, using your blended tax rate as a simplified stand-in for the full multi-year MACRS schedule.

Cash incentive is whatever state, utility, or grant funding you enter directly — it isn't estimated by this calculator, since these programs vary too much by location to default sensibly.

Total incentive and net cost combine all three sources, and effective discount expresses that total as a percentage of gross cost, useful for comparing projects of different sizes on equal footing.

What this calculator doesn't model

This is a simplified planning estimate, not a substitute for project-specific tax advice. It doesn't model the year-by-year timing of MACRS deductions, alternative minimum tax interactions, tax equity or transferability structuring for monetizing credits beyond your own tax liability, financing costs, or the interaction between multiple overlapping incentive programs with their own caps and eligibility rules. Confirm your project's specific ITC rate, bonus-adder eligibility, and depreciation elections with a qualified tax professional before finalizing project economics.

Common ways to use this calculator

Comparing project economics

See how ITC rate, bonus adders, and state incentives shift net cost across candidate sites.

Sizing a financing request

Estimate the net cost a loan or lease needs to cover after incentives are applied.

Evaluating bonus-adder eligibility

Compare the net-cost impact of pursuing domestic content or energy community qualification.

Talking to a tax advisor

Walk in with a concrete estimate of ITC, depreciation, and incentive value to refine together.

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 ITC eligibility, bonus-adder qualification, and depreciation treatment with a qualified tax professional before making investment decisions.

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FREQUENTLY ASKED QUESTIONS

Questions about the solar investment tax credit calculator.

Clear answers about the ITC, bonus adders, depreciation, and monetizing the value.

What is the Section 48E investment tax credit?

Section 48E is the technology-neutral federal investment tax credit that replaced the older Section 48 ITC for clean energy projects placed in service starting in 2025. For commercial solar, it offers a base credit of 6% of eligible cost, rising to 30% if the project meets prevailing wage and apprenticeship requirements — which most commercial-scale projects do, since the requirement generally applies once construction starts.

How do the ITC bonus adders work?

On top of the 30% base rate, three bonus adders can stack: 10% for meeting domestic content thresholds on steel, iron, and manufactured products; 10% for siting the project in an energy community, such as a former fossil-fuel site or coal-community census tract; and 10–20% for projects that qualify under the low-income community or Tribal land bonus program, which has limited annual capacity allocated through an application process. Stacked together, the maximum reaches 70%.

Why does claiming the ITC reduce my depreciable basis?

Under IRC §50(c), claiming the ITC requires reducing the property's depreciable basis by half the credit's value — not the full amount. That's why this calculator computes MACRS depreciation on cost minus 50% of the ITC value, rather than on the full system cost or on cost minus the full ITC.

Why does the calculator use a flat tax rate instead of the year-by-year MACRS schedule?

Full 5-year MACRS with the half-year convention spreads deductions across six tax years (roughly 20%, 32%, 19.2%, 11.52%, 11.52%, and 5.76%). Under current bonus-depreciation rules, however, businesses can typically elect to deduct a large majority of that basis in the first year the asset is placed in service. This calculator applies your blended tax rate to the full depreciable basis as a simplified estimate of that combined multi-year benefit's value — useful for comparing project economics, but not a substitute for your accountant's actual depreciation schedule and elections.

What blended tax rate should I use?

Start with the flat 21% federal corporate rate if your business doesn't pay state corporate income tax, or add your state's corporate rate for a blended figure — commonly 21–28% combined. Pass-through entities (LLCs, partnerships, S-corps) should use the owners' effective personal tax rate instead, since the deduction flows through to their individual returns rather than being taxed at the corporate level.

What state or utility incentives should I include?

Common categories include state performance-based incentives (such as New Jersey's TREC program, Massachusetts SMART, or New York's NY-Sun commercial block), USDA REAP grants covering up to 50% of project cost for eligible rural businesses, and utility-specific commercial rebates. These vary enormously by state and utility territory, so check your local program's current rules and caps rather than relying on a default.

Is this calculator only for solar, or does it work for other technologies?

Section 48E is technology-neutral and covers solar, wind, geothermal, and several other clean-energy technologies at the same base rates and bonus structure. The dollar math here — ITC value, basis reduction, and depreciation shield — applies the same way regardless of technology, though this calculator's supporting content is written with solar projects in mind.

Does this apply to residential solar too?

No. Residential solar uses the separate Section 25D residential clean energy credit, which is a simple 30% credit against a homeowner's personal tax liability with no depreciation component, since homeowners don't depreciate personal-use property. This calculator is built for commercial and business buyers who depreciate the asset on their books.

Can I actually monetize the full ITC and depreciation value?

Only if you have enough tax liability to absorb the credit and deductions in the relevant years — otherwise they carry forward, subject to IRS rules, rather than paying out as cash. Many commercial projects, especially larger ones, use tax equity partnerships or transferability provisions to monetize credits they can't fully use themselves; that structuring affects the net value you actually realize and isn't modeled here.

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.