Eight calculators covering the numbers behind an invoice — totals, VAT, GST, sales tax, late fees, due dates, hourly billing and freelance rates. Every one runs in your browser, shows its working, and hands the result straight to the invoice generator.
Line items, discount, tax and shipping to a final total.
Add VAT to a net price or extract it from a gross amount.
CGST/SGST split for intra-state, IGST for inter-state.
US state plus local rates, added or backed out.
Interest on overdue invoices, daily, monthly or annual.
Turn Net 15/30/60 into an exact calendar date.
Hours × rate, with an overtime block at a multiplier.
Target income to the hourly rate you must charge.
These calculators are not a separate product bolted onto the side of the invoice generator. They are the front half of the same workflow: you establish the correct numbers, then carry them into the generator so the PDF matches what you calculated, to the cent.
Nothing you type is uploaded and no account is required, in the calculators or in the generator. All of the arithmetic runs locally in your browser, which is the same privacy model the invoice tool has always used.
Each calculator shows the formula behind its result rather than just a number. That is deliberate: when a client or an accountant queries a figure, you can point at exactly how it was produced instead of re-deriving it from memory.
Yes, all eight are free with no usage cap, no account and no watermark. They run entirely in the browser.
Yes. Each calculator links to the matching generator so the figures you just established can be used directly, rather than being retyped and risking a transcription error.
Standard headline rates for the supported countries are included as presets and are reviewed periodically, but rates change and local variations exist. Always confirm the current rate for your specific supply and jurisdiction.
Yes. The arithmetic is currency-agnostic — changing the currency label does not alter the calculation, it only changes how the result is presented.