Best RSU Tax Calculators & Equity Comp Tools (2026)

The best RSU tax calculators fall into three groups by job: free tax modelers (EquityTax, Equity Simplified), cap-table platforms (Carta, Pulley), and equity-financing advisors (Secfi, EquityBee). The right one depends on whether you need tax math, cap-table management, or liquidity.

That three-way split is the honest version of the answer, and it is the reason this page is not a leaderboard with a single winner. A tool that brilliantly administers a startup's cap table is not the tool that tells you what you'll owe when $100,000 of RSUs vests next month. And the advisor who can lend you the cash to exercise pre-IPO options is not the free web form you'd reach for to sanity-check a withholding shortfall. Below, the real options are grouped by the job they actually do — and we say plainly where EquityTax loses.

The best RSU tax calculators 2026, at a glance

There are three categories of equity compensation tools, and most searchers really only need one of them at a time. Free RSU tax calculator tools answer "what will I owe?" Cap-table platforms answer "who owns what, and what's the 409A?" Financing and advisory tools answer "how do I pay for the exercise — or the tax — before I have liquidity?"

The table below maps the tools we evaluated across the six dimensions that actually decide the choice. Every third-party pricing or feature claim here should be re-checked against that vendor's live page before you rely on it; pricing and feature sets change often, and we describe the pricing model rather than a dollar figure wherever a number isn't currently citable.

The takeaway is structural, not promotional: no row wins every column. A free no-signup modeler wins on tax math and friction; a cap-table platform wins on administration; a financing product wins on liquidity. Pick the row that matches your job.

How we evaluated these tools (the dimensions that matter)

We scored every tool on the same six dimensions, because "best" only means something once you fix the job-to-be-done. Here's what each dimension means and why it matters.

• Price model — free, freemium, advisory-fee, or AUM-based. We name the model, not an unverifiable number.
• What it calculates — whether the tool produces an actual tax estimate, or whether tax is a side feature (or absent).
• Equity types covered — RSU, ISO, NSO, ESPP, and 83(b) restricted stock are taxed under different rules; a tool that only handles RSUs won't model an ISO exercise.
• State coverage — a $100K vest can cost $9,300 in California and $0 in Texas or Washington, so state handling is not optional.
• Signup required — some tools gate the result behind an email or an account; others don't.
• Best-for persona — the single user this tool actually serves best.

On methodology and recency: every pricing or feature claim about a third-party tool should be verified against that vendor's own live product or pricing page at the time you read this, and we re-verify the whole list annually (and bump the review year) by December 31. We deliberately describe pricing models rather than quoting dollar figures we can't currently cite.

What does a correct estimate of the tax on your equity actually have to get right? IRS Publication 525 is the controlling source for compensatory equity: the fair market value of vested RSUs is ordinary income, restricted property follows the substantial-risk-of-forfeiture rules, and an 83(b) election changes when that income is recognized. A tool that ignores any of those isn't estimating your tax — it's guessing. (For the underlying mechanics, see how RSUs are taxed and the 83(b) election.)

Free tax modelers: the best RSU tax calculators 2026 for the number

If all you need is the number — what you'll owe when RSUs vest or when you exercise ISOs — a free tax modeler is the right category, not a cap-table or financing product. This is the category EquityTax competes in, and competes well.

The single concept these tools exist to surface is the withholding gap. Employers withhold federal supplemental income at a flat 22% up to $1M (the IRS supplemental wage rate), but most RSU recipients land in a higher bracket — so 22% withheld routinely under-collects against a marginal rate as high as 37%. The chart below shows how the effective rate climbs above that 22% line as total comp rises.

The gap is the whole point: at higher comp levels the 22% RSU withholding gap leaves a four- or five-figure balance due at filing that a good calculator surfaces in advance. (We go deep on the mechanics in the 22% RSU withholding gap.)

EquityTax — Best for: a new RSU or ISO holder who just wants the number, with no signup.

• Pros: Free and no-signup; models RSU, ISO (including AMT), NSO, ESPP, and 83(b); multi-state coverage; built on IRS-grade tax logic and worked examples.
• Cons (the honest part): EquityTax is not a cap-table platform, a brokerage, or a financing/lending product. If you need to administer a company's equity, manage a 409A, or borrow cash to exercise, this is the wrong tool — and we say which tools lead there below.

That limitation is deliberate. EquityTax does one job: produce a defensible tax estimate for your equity, fast, without an account. The full suite is described in EquityTax's free calculator suite.

Broker award calculators (Fidelity, Schwab, E*Trade) — Best for: employees who already hold their shares at that broker.

• Model: Free, bundled with a brokerage account. Calculator features vary by broker and tend to focus on the awards you already hold there.
• Trade-off: Convenient if your shares already sit there, but tax handling tends to be narrow (often RSU/ESPP-centric) and state coverage is limited.

Lightweight, free single-purpose calculators — Best for: a quick second opinion on one scenario, with no account.

A few independent calculators are genuinely good and ask for nothing — useful as a cross-check even though none is a full multi-equity planning suite:

• Equity Simplified — free, no-signup AMT, ISO-planning, and RSU calculators that itemize regular income tax, AMT, Social Security, Medicare, NIIT, and state tax, and show the underlying math rather than a black-box number.
• Country Tax Calc — a free, no-signup RSU calculator built around the 22% withholding gap, covering federal, state, and FICA on a given vest.
• National Tax Tools — a free, no-signup AMT calculator that models the ISO bargain element and the 2026 AMT exemption phase-out on Form 6251; it states plainly that it does not model state AMT or AMT credits.
• The wider field — beyond those, many independent calculators are Google-Sheets templates or email-gated lead magnets of uneven quality, and some quietly skip state tax or AMT. Cross-check anything important against a tool that shows its assumptions.

Cap-table & equity management platforms

These platforms are not tax calculators, and they don't pretend to be — their core job is administering equity, not estimating your personal tax. If your question is "who owns what, what's our 409A valuation, and how do we track exercises," this is your category.

• Carta — a cap-table management platform for companies (cap-table administration, 409A valuations, exercise and grant tracking). Pricing is company-side and subscription-based, with 409A valuations included in its paid plans.
• Pulley — cap-table management and equity (and token) administration on a similar company-side, subscription model built for founders and finance teams.
• Cake Equity — equity and cap-table management aimed at startups, on a company-side subscription model that covers grants, 409A valuations, and compliance filings.

These platforms lead on cap-table management, full stop — EquityTax does not compete here and isn't trying to. Where they're weaker for an individual employee is the thing you came for: a personal, state-aware tax estimate. Any tax view tends to be secondary to the administration job. So if you're an employee asking "what will I owe," you'll still want a dedicated modeler alongside whatever platform your company runs.

Equity financing & advisory tools

These tools solve a money problem, not a math problem: how do you fund an exercise — or the resulting tax bill — before you have liquidity? That's a different job from estimating tax, and it's a job EquityTax does not do.

• Secfi — financial planning plus financing and liquidity products for startup employees, combining advisory with non-recourse financing against options and secondary-sale facilitation.
• EquityBee — a marketplace that connects employees who want to exercise options with accredited investors who fund the exercise, on a non-recourse, deal-based model.
• ESO Fund — provides non-recourse funding for the strike price and the associated taxes in exchange for a share of the upside if the company reaches liquidity.
• Harness (formerly Harness Wealth) — a marketplace that connects equity holders with vetted tax-advisory firms, plus its own tax-advisory service; check current fees and terms on their site before engaging.

Why does financing even become a decision? Often because of where you live and when the tax hits. Exercising ISOs can trigger AMT in the year of exercise even though you haven't sold a share, and a big RSU vest lands as ordinary income in your resident state. The chart below shows how the same $100K of equity income is taxed very differently by state.

When the same vest costs $9,300 in California, about $6,850 in New York, and $0 in Texas or Washington, the state line can be the difference between paying cash and needing to finance. (See the full state tax on equity income breakdown.)

These products lead on financing and liquidity — EquityTax is a free estimator, not a lender or an advisor, and we won't pretend otherwise. The honest pairing is to model the bill with a free calculator first, then talk to a financing or advisory product if the number is bigger than your cash on hand. For the timing trap that drives a lot of these decisions, see IPO lock-up and tax-due timing and the ISO alternative minimum tax (AMT).

Why the tax math itself is the hard part

Here's the seam that separates a real tax modeler from a tool that bolts on a tax estimate as an afterthought: the rules are genuinely fiddly, and they differ by equity type. The IRS is explicit that stock options create tax at multiple moments. As IRS Topic No. 427 puts it:

"If you receive an option to buy stock as payment for your services, you may have income when you receive the option, when you exercise the option, and when you sell the option or the stock received when you exercise the option."

That single sentence is why ISOs and NSOs diverge so sharply at exercise. The chart below compares the two on the same grant.

NSOs tax the spread as ordinary income at exercise; ISOs trigger no regular tax at exercise but feed the spread into AMT as a preference item, computed on Form 6251 (see ISO vs NSO at exercise). A cap-table platform tracks that you exercised; a tax modeler tells you what it costs.

Which tool should you use? (by persona)

Match the persona to the category and you've made the decision. Here's the short version.

• New RSU grant holder who just wants the number → a free tax modeler. You need the withholding-gap estimate and your state's bite, fast, with no signup. EquityTax fits here; so do solid independent calculators.
• Founder, operator, or equity admin → a cap-table platform (Carta, Pulley, Cake Equity). You're administering equity for a company, not estimating one person's tax.
• Pre-IPO ISO holder who needs exercise cash → a financing or advisory product (Secfi, EquityBee, ESO Fund, Harness). Your constraint is liquidity, not arithmetic — though you should still model the tax first.

If your need is the first one — just the tax number, no account, multi-state — that's exactly the niche EquityTax was built for, and you can model an AMT calculator for stock options scenario or an RSU vest in a couple of minutes. If your need is the second or third, use the leaders we named; we're not the tool for those jobs and won't pretend to be.

Frequently asked questions

What is the best free RSU tax calculator?

There are several free RSU tax calculators, and the best one for you depends on whether it covers your state and equity types (RSU, ISO, ESPP) and whether it forces a signup. Prioritize a tool that models the 22% supplemental-withholding gap, handles your resident state, and shows its assumptions. EquityTax is free and no-signup with multi-state coverage; broker calculators are convenient if your shares already sit there.

Do RSU tax calculators account for the withholding gap?

Good ones do. Employers typically withhold federal supplemental income at a flat 22% up to $1M, which can under-collect for high earners whose marginal rate runs up to 37% (IRS Publication 525). A calculator that doesn't surface that gap will understate what you owe at filing. Check that the tool shows both the amount withheld and the balance due.

Which tools calculate ISO AMT?

Dedicated tax modelers compute the ISO bargain element (spread at exercise) as an AMT preference item; cap-table platforms usually don't, because AMT isn't their job. AMT is calculated on Form 6251, and Topic No. 556 explains why exercising ISOs can trigger it even without a sale. If ISOs are in play, use a tool that explicitly models AMT, such as an AMT calculator for stock options.

Is Carta a tax calculator?

No. Carta is primarily a cap-table management platform — it administers equity, 409A valuations, and exercise tracking for companies, not a personal tax estimate for an individual employee. For the tax number, pair it with a dedicated modeler.

What's the difference between Secfi, EquityBee, and ESO Fund?

All three help fund the exercise or holding of equity, but they differ in model. Secfi pairs financial advisory with financing and liquidity products; EquityBee runs a marketplace matching employees with accredited investors who fund the exercise; ESO Fund supplies non-recourse cash for the strike price and associated taxes in exchange for a share of the upside. Because fees, terms, and eligibility change, confirm the current specifics on each vendor's own site before committing.

Do I need to sign up to use a tax calculator for equity?

Some tools require a signup or capture your email before showing the result; others, including EquityTax, do not. If you want a quick estimate without handing over contact details, choose a no-signup calculator. Broker calculators generally require an existing account.

Are these calculators a substitute for a CPA?

No. These tools estimate — they don't replace professional advice tailored to your full situation. Use a calculator to get oriented and to ask better questions, then consult a qualified tax professional before you act on a large exercise, sale, or election. Your outcome could differ based on facts a calculator can't see.

How we maintain this list

This is an evergreen reference, not a churn page. The commitment is concrete: every vendor's pricing and product page gets re-verified, and the review year is bumped, by December 31 each year. Tax figures are tied to IRS sources, not vendor marketing, and any third-party claim that can't be verified on a live page is dropped rather than approximated.

EquityTax appears here as one strong option in the tax-modeling category — not the best tool overall, and explicitly behind Carta and Pulley on cap-table management and behind Secfi, EquityBee, and ESO Fund on financing. If all you need is the free tax number with no signup, here's ours.