Overview

TelosTax is a browser-based tax-preparation app for people filing individual returns for tax year 2025. It is best suited to filers who value open-source software and offline use, but its stated federal scope is limited to that tax year. Choose it only if 2025 is the year you need.

The project describes more than 90 tax features aimed at covering about 85–90% of individual filers. That is a broad target, not a guarantee that a particular return is supported. Federal coverage centers on Form 1040, Schedules A–H, SE and D, plus more than 30 supplemental forms; the project also reports calculations for all 50 states and Washington, DC. Its published scope specifies federal support for 2025, so filers handling another year should look elsewhere.

TelosTax lists 41 IRS and 43 state PDF templates with auto-populated field mapping. It also says calculations can be traced to tax law and IRS materials, including the Internal Revenue Code and form instructions. That emphasis on traceability is useful for readers who want to examine the basis of a calculation, but it does not mean every tax situation is covered.

Key features

Guidance and deduction finding

AI tax guidance and deduction finding are listed features, alongside document import. Together, they address common preparation tasks: getting help with tax questions, bringing in paperwork and spotting possible deductions. Their usefulness depends on whether a filer is comfortable enabling the optional AI features and supplying an Anthropic API key.

Privacy and calculation design

Private Mode is described as fully offline, making it the more compelling option for people who prefer not to use AI services. BYOK Mode enables AI chat, expense scanning and document extraction through the user's own Anthropic key; TelosTax says it strips personally identifiable information before transmission. The project also states that tax data is encrypted at rest using AES-256-GCM.

The calculation engine is described as a standalone pure-function library with no database access or network calls in its calculation layer. That separation and the stated legal traceability are meaningful design choices for a tax app. The repository reports more than 6,100 tests across 139 test files, though a test count alone cannot establish how well a particular return is handled.

Pricing

TelosTax's Free plan costs 0.00 USD per free and is described as a free, open-source tax-preparation app for tax year 2025. The maker does not publish plan prices on its site, so the free plan is the only stated price point; there are no published paid-plan terms to compare. Personal taxpayers get the listed AI guidance and deduction-finding features, while optional AI functions require the user's own Anthropic API key. That makes the no-price-entry point appealing, but users should not assume the AI service itself is included.

Platforms

The app is browser-based, and the project describes it as offline-capable and installable on desktop and mobile. It is listed for Android, iOS, Linux, macOS, web and Windows, giving it a wider platform reach than a web-only tax tool. Offline capability and Private Mode may suit people who want to prepare without a network connection; availability across platforms does not change the 2025 federal-year limit.

Who it's for

TelosTax fits individual filers preparing a 2025 return who want a free, open-source option, need federal and state coverage, and value offline operation or traceable calculations. It is less suitable for anyone filing a different federal tax year or whose circumstances fall outside its stated individual-filer coverage. Filers who want AI assistance must also be willing to use their own Anthropic API key.

Pros and cons

Pro: A free, MIT-licensed open-source app makes the stated 2025 preparation offering accessible without a listed subscription price.
Pro: Federal and state calculations, PDF templates and a substantial set of forms aim to cover a wide range of individual returns.
Pro: Offline Private Mode and the project's encryption and calculation-layer design will appeal to privacy-conscious filers.
Con: Published federal support is for tax year 2025 only, which rules it out for other filing years.
Con: Optional AI tools depend on the user's Anthropic API key, adding a setup requirement for people who want those features.
Con: The coverage target is not a promise for every return, so filers with unusual circumstances should verify fit before relying on it.

Alternatives

For a different free-first option, compare H&R Block Online, whose free plan is limited to simple tax situations and Form 1040. TaxAct may suit eligible standard-return filers seeking free federal filing, though state filing costs extra. TurboTax also offers a free edition for simple Form 1040 returns, with eligibility limited to simple returns.

Taxation.ai is another free option, with one federal return per year, five document uploads, a basic AI assistant and deduction finder. Taxfix, EZTax, Quicko and TaxTim are alternatives to consider if you want to compare other tax-preparation products.

Verdict

TelosTax is a strong fit for individual filers preparing a 2025 return who want a free, open-source app with offline use, broad stated federal and state coverage, and optional document and AI tools. Its privacy-focused design and traceable calculations are reasons to shortlist it. Look elsewhere if you need federal support for another tax year, or if your return falls outside the app's stated individual-filer scope.

	TaxTim	TelosTax
Free plan	No	Yes
Free trial	No	No
Paid from	—	Free
Open source	No	No
Platforms	Android, iOS, Web	Android, iOS, Linux, macOS, Web, Windows
Free plan	Yes	Yes
Taxpayer types	both	personal
AI tax guidance	Yes	Yes
Document import	Yes	Yes
Deduction finding	Yes	Yes
Expert review	Yes	—
Filing support	—	both

TaxTim vs TelosTax

TaxTim

TelosTax