Sample work · Calculators & Tools
Quote Calculator: Volume Discount, Voucher, Shipping, and VAT, down to the exact cent
A browser-based calculator that computes a quote step by step. Every displayed amount was automatically checked against an independent recalculation, including half cents and volume tiers.
Sample work (demo), not a client job. Built as a trial task with invented example data; the check figures below come from the automatic test run and are not polished.
What was built
- Single page, pure HTML and JavaScript, without any libraries and without a server
- Discount tiers, voucher, shipping cost threshold, and VAT with commercial rounding
- Invalid inputs are intercepted and explained instead of showing an incorrect total
How it was checked
Automatic test run on 2026-10-31, taken from the log (test data invented, figures measured):
- 41 quotes calculated via the interface, 287 displayed amounts compared against Python decimal (ROUND_HALF_UP), incl. half cents, volume thresholds 10/50, shipping threshold 100 EUR, VAT 19/7 % with proportional voucher
- 6/6 invalid inputs intercepted
- 0 deviations
Limits
What this sample does not cover, so nobody expects more:
- Calculation rules (volume discount, voucher, shipping threshold, VAT 19/7 %) are an example - actual customer rules must be defined in writing beforehand (esp. rounding per line item or per total)
- No saving/no sending of the quote, no PDF output (see sample pdf_word for that)
- Only EUR and German number formatting; currency conversion / foreign VAT (OSS, reverse charge) not covered
- Tested in headless Chromium; visual appearance not automatically evaluated
Something like this for your business?
Describe briefly what you need. You get a fixed price before I start; nothing happens without your yes.