german-insurance-number-validator

Validates German health insurance numbers — Krankenversichertennummer / Versichertennummer (KVNR): 1 letter + 9 digits with an official-style checksum.

The checksum logic has been tested against more than 100,000 German insurance numbers.

Requires Angular 19, 20, 21, or 22.

Terminology

| English | German | Abbreviation | | --- | --- | --- | | German health insurance number | Krankenversichertennummer, Versichertennummer | KVNR |

Features

• Standalone input component with label and built-in English error messages
• Reactive Forms validator (germanInsuranceNumberValidator())
• Pure helper isValidGermanInsuranceNumber() for use outside templates
• Empty values are treated as valid (pair with Validators.required when the field is mandatory)
• Works with formControl / formControlName via ControlValueAccessor

Validation rules

| Rule | Detail | | --- | --- | | Length | Exactly 10 characters | | Format | First character is a letter (A–Z, case-insensitive); the rest are digits | | Checksum | Letter mapped to two digits (A = 01 … Z = 26), then alternate multiply by 1 and 2, cross-total, compare sum % 10 to the last digit |

Example of a valid number: A123456780.

Installation

npm install german-insurance-number-validator

Peer dependencies: @angular/core, @angular/common, and @angular/forms (Angular 19–22).

Standalone input component

import { Component } from '@angular/core';
import { FormControl, ReactiveFormsModule } from '@angular/forms';
import { GermanInsuranceNumberInputComponent } from 'german-insurance-number-validator';

@Component({
  selector: 'app-profile-form',
  imports: [ReactiveFormsModule, GermanInsuranceNumberInputComponent],
  template: `
    <german-insurance-number-input
      [formControl]="insuranceNumber"
      label="German insurance number"
      [required]="true"
    />
  `,
})
export class ProfileFormComponent {
  insuranceNumber = new FormControl('');
}

Input options

| Input | Type | Default | Purpose | | --- | --- | --- | --- | | label | string | German insurance number | Visible field label | | placeholder | string | e.g. A123456789 | Input placeholder | | required | boolean | false | Marks the field required and shows the required message | | requiredMessage | string | German insurance number is required. | Override required error text | | invalidMessage | string | Please enter a valid German insurance number. | Override checksum/format error text | | inputId | string | auto-generated | Links the label to the input | | showErrorsWhen | 'touched' \| 'dirty' \| 'submitted' | 'touched' | When to show validation messages |

Validator only

Use this when you already have your own input UI:

import { FormControl, Validators } from '@angular/forms';
import {
  germanInsuranceNumberValidator,
  VALIDATION_ERROR_KEY,
} from 'german-insurance-number-validator';

const control = new FormControl('', [
  Validators.required,
  germanInsuranceNumberValidator(),
]);

if (control.errors?.[VALIDATION_ERROR_KEY]) {
  // invalid insurance number
}

Invalid values set:

{ "validationError": "Please enter a valid German insurance number." }

Pure utility

import { isValidGermanInsuranceNumber } from 'german-insurance-number-validator';

isValidGermanInsuranceNumber('A123456780'); // true
isValidGermanInsuranceNumber('A123456789'); // false
isValidGermanInsuranceNumber('');           // true (optional field)

Reliability

The checksum algorithm used by this package has been tested over 100,000+ German insurance numbers.

License

MIT

Source: github.com/ITRIX/german-insurance-number-validator