This crate implements Skatteverket monthly tax tables 29 through 42 and the annual preliminary-tax formulas from SKV 433, edition 36, for income year 2026.
The calculations use the same assumptions as the published tables and are not an individualized final tax assessment.
cargo run --bin tax-annual -- 34 1 216000
cargo run --bin tax-monthly -- 34 1 18000Arguments are tax table, column, and gross income in whole SEK.
The native egui application includes a reopenable income calculator for salary, one-time compensation, occupational pension, and dividends within the owner-managed company's gränsbelopp. It calculates the withholding applied by main and secondary payers (including percentage adjustment decisions), reconciles withholding with annual final tax, and estimates progress toward the 2026 PGI and SGI ceilings. Regular salary rows can estimate an ITP 1-equivalent employer pension contribution, while one-time salary rows can model an editable salary exchange, the employer uplift, the remaining pension allowance, and the taxable cash payment. The 35-percent allowance can optionally use a fixed, editable pensionable salary from the preceding tax year instead of the current-year salary basis. An optional confirmed total for pension and insurance costs before the exchange can replace the app's component estimates in the allowance calculation. Vacation compensation is pensionable by default in the ITP 1-style model and shows its estimated additional employer contribution separately. The editable scenario default is 5.4% of monthly salary per paid day, a common collective-agreement calculation, and the percentage, pensionability, and actual contribution amounts remain editable for individually agreed terms. Recurring salary rows can also use their 12-month projection as the annual income basis behind a percentage jämkning decision. The annual result then shows the calibration explicitly while preserving the row's actual payment dates. Partial first and last months divide by the calendar days in that month by default; an optional row setting instead uses the annual daily rate (monthly amount × 12 / 365). The app also estimates the 2027 3:12 gränsbelopp for qualified shares: the ownership-adjusted basic amount, wage-based allowance using 2026 payroll, the 50-times-salary cap, acquisition-cost interest, and saved allowance. Salary rows marked as sourced from the owner's company or group feed the owner's 2026 cash compensation and, in one-person-company mode, the complete payroll basis. For a normal privately held Swedish AB, the preliminary 2027 view treats the 20-percent amount as personal tax declared on K10 in 2028 rather than tax withheld by the company when the dividend is paid. The desktop app restores the selected table, age group, jämkning settings, and complete income plan between launches. If later pension changes make an existing salary exchange exceed its allowance, the plan is marked invalid and reports the new maximum instead of silently calculating from inconsistent inputs.
cargo run -p swedish-tax-guiThe GUI is a separate workspace package. A normal cargo build from the
repository root builds both the core/CLI package and the graphical application.
The GUI saves the current plan model without schema version markers or migrations. If saved data cannot be read, it is preserved and saving is disabled for that session.
The swedish-tax-ios workspace crate exposes the tax core through a typed C ABI.
Build ARM64 device and Apple Silicon simulator slices and package them as an
XCFramework with:
rustup target add aarch64-apple-ios aarch64-apple-ios-sim
cargo xtask ios --releaseThe task first regenerates ios-ffi/include/SwedishTaxFFI.h from the public
#[repr(C)] Rust types and extern "C" functions using its pinned cbindgen
library dependency. The generated header is checked in for review and Swift
module import; cargo test --workspace fails if it drifts from the Rust ABI.
The default artifact is target/ios/SwedishTaxCore.xcframework. The iOS Xcode
project consumes that location through its persisted
RUST_CORE_ARTIFACTS_DIR build setting; --output PATH remains available for
other consumers and packaging workflows.
Compile the same C interface for the browser with:
rustup toolchain install 1.98.1 --component rust-src --target wasm32-unknown-emscripten
RUSTUP_TOOLCHAIN=1.98.1 cargo xtask wasm --releaseThe task regenerates the shared C header and produces
target/wasm/libswedish_tax_ios.a and target/wasm/SwedishTaxFFI.h. It builds a
static library for wasm32-unknown-emscripten; the consuming .NET application
links that library into its runtime with dotnet publish.
--output DIRECTORY selects the output directory. --target-dir DIRECTORY
selects Cargo's build cache, otherwise CARGO_TARGET_DIR or the workspace's
target directory is used. The default output is wasm under that build cache.
Relative paths resolve from the Rust workspace. Omit --release for a debug build.
The default compiler flags are the configuration verified with .NET SDK 10.0.301:
-C panic=abort -C target-cpu=mvp -C target-feature=-bulk-memory-opt,-call-indirect-overlong.
--rustflags FLAGS replaces that preset so a consumer can supply its pinned settings.
The task rebuilds Rust's standard library with -Z build-std=std,panic_abort and
scopes RUSTC_BOOTSTRAP=1 to the target build. Rust warns that the LLVM feature
flags are unstable. Compiler changes require browser parity verification.
The same C ABI powers the
Blazor calculator.
Its build script verifies the provider pin, generated declarations and fixture
copies, invokes cargo xtask wasm, and supplies the library to the .NET linker.
C# calls generated P/Invoke declarations, with all 10 functions, 21 structures and result cleanup covered by
native/browser tests. The editor interface returns structured validation,
invalid-plan totals, row/monthly amounts, vacation/pension details, exchange allowance
previews and policy defaults. Both clients map these Rust results; the saved exchange
request remains unchanged when its preview is limited to the permitted maximum.
See the editor API contract.
The browser build pins its compiler configuration and uses abort-on-panic
behavior. Its supported build and ownership contract are described in the
consumer engine guide.
The iOS artifact and build workflow use the XCFramework described above.
The C interface supports the current generated header only. Rebuild consumers and the Rust library together when its types or exports change.
tests/fixtures contains 17 checked-in input plans and expected results generated
directly from the Rust core. They verify client mappings for ordinary and mixed income,
proration, vacation, pensions, salary exchange, dividends and invalid inputs.
Generate or check them with the native developer tool:
cargo xtask fixtures
cargo xtask fixtures --checkThe Blazor repository checks in exact copies for its native and browser tests; its native-engine build rejects any difference from the pinned provider. Its production calculations call the shared C ABI through P/Invoke, with the Rust library compiled to WebAssembly and linked into the .NET runtime. The fixture JSON is test data, independent of that compilation target. See the shared fixture guide for generation, schema validation and consumer synchronization.
- SKV 433 technical specification
- Official monthly tables
- 2026 withholding on one-time payments
- Worked examples
- 2026 pensionable income (PGI)
- Sickness-benefit qualifying income (SGI)
- 2026 ITP 1-equivalent pension-contribution benchmark
- ITP pensionable salary, including vacation compensation
- Common 5.4% vacation-compensation calculation
- Employer pension-cost deduction rules
- Changed 3:12 rules for income year 2026
- 2026 income-base amount used by the preliminary 2027 estimate
Development instructions are in CONTRIBUTING.md. This project is available under the MIT License.