Business Tools

What the business calculators cover

Fifteen tools for the working side of running something: invoicing clients, pricing work, judging whether an investment is worth it, chasing late payments, and the small digital utilities that save time along the way. No account required, and everything runs in the browser.

Invoicing, pricing, and rates

• Invoice generator — line items, tax, and totals in a clean preview you can print or save as PDF.
• Markup and margin — the difference between the two, and how to price from cost or from a selling price.
• Freelance hourly rate — the rate you need to cover income, expenses, tax, and unpaid time.
• ROI — return on an investment as a percentage of what you put in.
• Cap rate — a property’s net operating income over its price, for rental comparisons.

Cash flow and payback

• Late payment interest — what overdue invoices accrue at a chosen rate.
• Payback period — how long an investment takes to return its cost.
• Business days — working days between two dates, excluding weekends.

Workflow and productivity

• Pomodoro timer — timed focus blocks with breaks.
• Word counter — words, characters, and reading time for a piece of text.
• Time zone converter — line up a meeting time across time zones.

Digital utilities

• Hex / RGB converter — move between colour codes used in design and CSS.
• File size calculator — convert and estimate file sizes and transfer times.
• Password strength — how long a password might resist guessing.
• Markdown to HTML — turn Markdown into clean HTML.

How to use them together

1. Set your rate deliberately. Start with the freelance hourly rate so every quote is grounded in what you actually need to earn.
2. Price consistently. Use markup and margin to translate cost into a selling price rather than guessing.
3. Invoice properly. Number each invoice, include terms, and apply the correct tax rate.
4. Follow up on time. Late payment interest turns a polite reminder into a specific, defensible number.
5. Check before you commit. ROI and payback answer “should I spend this?” before the money leaves.

Is the invoice generator really free?

Yes. Creating an invoice, previewing it, and printing or saving it as a PDF is free, with no account and no watermark on the free version. The paid upgrade is a branded PDF with your own logo and the full export suite, part of the one-time ToolkitHQ Pro purchase that covers every tool.

Common mistakes

• Confusing markup and margin. A 50% markup is only a 33% margin; mixing them up under-prices work.
• Ignoring non-billable time. A rate built only on billable hours hides the hours spent on admin, quoting, and marketing.
• Invoicing without terms. Without a due date and payment method, there is nothing to enforce and no way to charge late interest.
• Judging an investment on revenue alone. ROI and payback include the cost; a busy project can still lose money.
• Reusing a weak password across tools. Strength estimators exist because the cost of a breach is far higher than the effort of a better password.

Frequently asked questions

Do I need an account to save my invoices or clients?

No. There are no accounts anywhere on the site. Header details sync into the URL so a link reopens the same invoice, and recent results are stored locally in your browser.

Are these tools suitable for tax filing?

They are estimating and planning tools, not accounting software. Use them to price, quote, and check figures, then keep proper records and confirm tax treatment with an accountant.

Why does the cap rate matter for a rental?

It expresses a property’s income as a percentage of its price before financing, which makes two rentals comparable regardless of how they are bought. It says nothing about mortgage costs, which is why loan tools sit alongside it.

If you bill hourly, the salary-to-hourly converter in the finance category helps set the underlying number, and the percentage calculator handles any discount or share a client asks about.