Free business tools and calculators for small businesses
Invoice, quotation and receipt makers, payment reminders, AR aging and statements, timesheet, margin and WhatsApp cost calculators, InvoiceNow checkers and ERP self-tests. Each one does a real job in a minute, in your browser. Free, no signup, and your data never leaves your computer. Singapore defaults (9% GST, PayNow, InvoiceNow), editable for anywhere.
Start here: what is costing your business money?
- SME Systems Health CheckTen honest questions, a score out of 20 and the one leak to fix first. About 60 seconds.
- Cost of Manual Work CalculatorWhat retyping, chasing and checking really cost your team in a year.
- ERP Readiness ScorecardEight questions on data, process, ownership and time: are you ready for a system, and what to fix first?
Get paid faster
- Overdue Invoice Reminder WriterDrop in your Xero or QuickBooks aged receivables; get the right reminder for every late customer.
- AR Aging Report GeneratorAging by customer, overdue %, DSO and a statement of account for every customer, from one export.
- Statement of Account GeneratorA statement for every customer with open invoices, aging and total due, as PDF.
- Invoice GeneratorPDF invoices and GST tax invoices with your logo, numbering and payment details.
- Receipt GeneratorPayment receipts with a PAID stamp for cash, PayNow, bank transfer or card.
Quote, sell and price
- Quotation GeneratorQuotes with GST, validity and terms; one click turns an accepted quote into an invoice or delivery order.
- Delivery Order GeneratorDelivery orders with a receiver signature block and no prices.
- Profit Margin CalculatorMargin, markup, price and break-even; reprice a whole list to a target margin.
- Markup CalculatorMarkup to margin and back, with the right selling price and GST.
Profit, cash and GST calculators
- Break-Even CalculatorUnits and sales you need to cover fixed costs, plus margin of safety.
- Gross Profit CalculatorGross profit, gross and net margin; works out cost of goods sold from stock.
- Price Increase CalculatorThe % change between two prices, and what to charge when costs rise.
- GST CalculatorAdd or remove 9% GST (or any rate), one amount or a whole list.
- DSO CalculatorDays sales outstanding, days beyond terms and the cash tied up.
- Invoice Due Date CalculatorDue dates on net 7 to net 90 and net 30 EOM, days overdue and late interest.
Buy, pay and staff
- Purchase Order GeneratorNumbered purchase orders with supplier, delivery date and terms, as PDF.
- Timesheet CalculatorHours, breaks, overnight shifts, overtime at 1.5× and pay for the week, with print and CSV.
- Month-End Close Cost CalculatorWhat a slow close costs in salary every year, and what a five-day close is worth.
WhatsApp and automation
- WhatsApp Business API Cost CalculatorYour monthly WhatsApp bill at Singapore rates, including the October 2026 change and provider plans.
- Make Credit CalculatorHow many Make credits your workflows really use, and which plan you need.
- ERP & Automation ROI CalculatorPayback period and 15-year value of a system, from your team size, hours and setup cost.
Grants, GST and InvoiceNow (Singapore)
- EDGE Grant CalculatorEstimate the EDGE grant and net cost of an ERP or digital project, with the S$30,000 sub-cap and eligibility checks.
- Inventory Software Cost CalculatorCompare 12 months of licence costs for Zoho Inventory, inFlow, Cin7 Core, Unleashed and Odoo for your users, locations and orders.
- InvoiceNow Deadline FinderYour GST status in, your InvoiceNow date out.
- Is My Software InvoiceNow-Ready?Check your accounting software against IMDA's accredited list.
- Free InvoiceNow SolutionsThe official free packages and their limits.
- InvoiceNow GrantsWhat you can actually claim.
- Providers vs Access PointsWhich one you need, and when.
Guides that go with the tools
Start here: Choosing and implementing a business system · Automation for small business · Singapore grants and InvoiceNow
Step-by-step guides on The Gantry, with worked examples and the automation that runs each job for you: Payment reminder email templates · How to calculate hours worked and overtime · WhatsApp Business API pricing · Make pricing and review · Order to cash, explained · When your business must use InvoiceNow · All free tools, with demos.
Questions
Are these business tools really free? Yes. No signup and no trial. The document makers and everyday calculators have no limits; the ERP planning calculators offer a free 20-minute review after a few runs, and you can keep using them either way.
Is my data safe? Everything runs in your browser. Your files and entries are never uploaded or stored on a server; your business details are remembered only on your own computer.
Do the tools work outside Singapore? Yes. Currency and tax rate are editable. Singapore specifics such as 9% GST, tax invoices, PayNow and InvoiceNow are built in as defaults.
Who builds these tools? Sayed Rashid, who works with business owners on automation and business systems. Each tool comes from a job owners were doing by hand every week.
Can I suggest a tool? Yes. Message Sayed on LinkedIn with the job you do by hand every week; the most common requests become the next free tools.
