Practical guides for tools people actually use.
Step-by-step guides for money, invoices, QR codes, budgeting and everyday business workflows, paired with free CalculatorAI tools so you can act immediately.
Short guides with the calculator, tracker or document tool already attached.
Read the decision, avoid the common mistake, then open the exact tool that handles the work.
- Guides
- 30
- Tool links
- 44
- Minutes
- 231
Featured guide
Pay Off Debt or Invest? A Practical Order
Debt7 min read
Pay off debt or invest? Compare APR, emergency savings and employer matches, with a worked example and free tools to build your next-step plan.
CalculatorAI Team · Aug 28, 2026
Read the guideTool Handbooks & Guides
Trading9 min
Position Sizing: How Much Should You Risk Per Trade?
Most blown accounts are a sizing problem, not a strategy problem. The 1% rule, the position size formula, and worked examples for stocks, forex and crypto.
Aug 27, 2026Read
Invoicing8 min
How to Turn a Quote into a Booked Job (UK)
A practical workflow for turning an enquiry into a priced, booked and paid job — without losing details across texts, spreadsheets and paper.
Aug 26, 2026Read
Investing9 min
How to Build Dividend Income (and Track Every Payment)
Yield on cost versus current yield, the only date with a deadline, what makes a dividend safe, and how much capital a monthly income actually needs.
Aug 21, 2026Read
Taxes8 min
No Tax on Tips and Overtime: What It Actually Does to Your Paycheck
The caps, the phase-outs, why only the premium half of overtime counts, and the one W-4 line that decides whether you see the money monthly or as a refund.
Aug 21, 2026Read
Invoicing9 min
How to Create an Invoice (and Where to Make One for Free)
Everything an invoice must contain, how to number, date and word it — plus an honest comparison of where to make one free, including our own generator.
Aug 17, 2026Read
Budgeting8 min
How Much Emergency Fund Do You Need? (3, 6 or 9 Months)
Three or six months of what, exactly? Size the fund on essential spending, not your whole lifestyle — with real US data and the math behind each target.
Aug 17, 2026Read
Investing8 min
How to Calculate Your Net Worth (and Track It Every Month)
Add up what you own, subtract what you owe — plus what counts, what does not, and why the monthly trend tells you far more than the number itself.
Aug 17, 2026Read
Documents6 min
How to Make a Restaurant Receipt (Free, No Design Skills)
What has to be on a restaurant receipt, how to handle tax and tips, and how to produce a clean PDF in a couple of minutes — free, no watermark.
Aug 13, 2026Read
Credit7 min
What Actually Moves Your Credit Score (and Roughly How Much)
Which credit habits move your score, how much each one weighs, and how long the damage lasts. Then estimate your own before you act.
Aug 13, 2026Read
Taxes9 min
Quarterly Estimated Taxes for Freelancers: A Plain-English Guide
Who has to pay US quarterly estimated taxes, the 2026 due dates, how to work out the amount, and the safe-harbor rule that stops you being penalised.
Aug 7, 2026Read
Budgeting8 min
How to Split Expenses With Roommates (Without an App or a Group Chat)
Split rent, bills and groceries fairly when incomes and room sizes differ. Four splitting methods, the settle-up math, and a free calculator you can share by link.
Aug 7, 2026Read
Engineering6 min
77% of Our Google Crawl Budget Went to the Same 222 Files
Google was re-crawling identical Next.js assets because Vercel Skew Protection mints new URLs every deploy. How we found it, and the fix not to make.
Aug 5, 2026Read
Invoicing8 min
What Should You Charge as a Freelancer? The Rate Formula
Your old salary divided by 2,080 is the wrong number. Here is the formula that works backwards from what you want to keep, with a worked example.
Aug 2, 2026Read
Housing8 min
Should You Refinance Your Mortgage? The Break-Even Math
Refinancing is one division problem: closing costs divided by monthly saving. Work out your break-even point, and the trap that raises your total interest.
Aug 2, 2026Read
Investing8 min
How to Calculate Capital Gains Tax (US Stock & Crypto)
How is capital gains tax calculated in the US? Learn short-term vs. long-term rates, wash-sale rules, and how to report stock and crypto sales.
Jul 29, 2026Read
Investing9 min
How to Maximize Your 401(k): Match & Contribution Rules
How does a 401(k) employer match work? Learn contribution limits, vesting rules, tax choices, and strategies to maximize your retirement savings.
Jul 29, 2026Read
Housing9 min
What Salary Do You Need to Buy a Home? Six Countries Compared
We ran the same mortgage on official data from six countries. The US has the cheapest housing per square metre in the study — and one of the heaviest burdens.
Jul 28, 2026Read
Investing7 min
Portfolio Diversification: How to Measure Yours (and Actually Improve It)
Diversification is more than owning many stocks. Learn what real diversification looks like, how to measure your concentration, and how to fix it.
Jul 25, 2026Read
Investing8 min
How to Track Your Investment Portfolio (Without a Spreadsheet)
Stop guessing what your portfolio is worth. A simple system to track holdings, cost basis, gains and allocation — free, no spreadsheet.
Jul 25, 2026Read
Trading8 min
Win Rate, Risk-Reward and Expectancy: The Only Trading Math That Matters
You can win 40% of trades and still be profitable. Learn how win rate, risk-reward and expectancy combine — and how to compute yours.
Jul 25, 2026Read
Trading8 min
How to Keep a Trading Journal (What to Track + Free Template)
A trading journal is the fastest way to stop repeating losing trades. Learn exactly what to log, the metrics that matter, and how to review it.
Jul 25, 2026Read
Money Habits7 min
What Your Daily Habits Actually Cost You in a Year
A $6 daily coffee is $1,560 a year and $22,500 over a decade if invested. See what everyday habits really cost — and how to cut the ones not worth it.
Jul 24, 2026Read
Debt8 min
Debt Snowball vs. Debt Avalanche: Which Pays Off Faster?
Snowball vs. avalanche run on the same four debts: which saves more interest, which keeps you motivated, and how to choose. With free payoff calculators.
Jul 24, 2026Read
Budgeting7 min
How to Do a Subscription Audit (and Cancel What You Forgot)
A 30-minute subscription audit: find every recurring charge across five hiding places, price each one per year, and cancel what you never use. Free calculator.
Jul 24, 2026Read
Rentals9 min
How to Track Rental Income and Expenses for Taxes
What to track for rental taxes: deductible expenses, repairs vs. improvements, depreciation, mileage and the records Schedule E needs — without a spreadsheet.
Jul 24, 2026Read
Budgeting6 min
The 50/30/20 Budget Rule: How to Split Your Paycheck
The 50/30/20 rule splits your take-home pay into needs, wants and savings. Learn how to calculate it with an example, and how to actually stick to it.
Jul 19, 2026Read
Invoicing7 min
How to Invoice a Client as a Freelancer (Free Template)
A clear, step-by-step guide to invoicing clients as a freelancer — what to include, how to set payment terms, and how to get paid on time. Free invoice tool.
Jul 19, 2026Read
QR Codes6 min
How to Make a Digital Business Card with a QR Code (Free)
Create a free digital business card as a QR code — people scan it and your contact saves straight to their phone. No app, and you can edit it anytime.
Jul 19, 2026Read
QR Codes6 min
How to Create a QR Code Menu for Your Restaurant (Free, No App)
Make a free QR code menu for your restaurant in minutes — no app, no monthly fee. Print it once, then edit the menu anytime without reprinting.
Jul 19, 2026Read
More practical guides are coming.
New walkthroughs will keep the same format: plain-English steps, honest tradeoffs and direct links to the working tool.