Marcus Reid
Finance Writer & CPA · 12+ years experience
Marcus is a licensed CPA with twelve years advising on personal finance, small-business tax, and mortgages. He breaks down calculators (mortgage, retirement, paycheck) into the decisions they actually help you make, not the math behind them.
Posts by Marcus Reid (15)
January 25, 2026 · Finance · 6 min read
Credit Card Interest: The Math Behind the Monthly Minimum
How credit card interest is actually calculated, what APR means in practice, and why making the minimum payment is a trap most people underestimate.
January 13, 2026 · finance · 6 min read
Why $1,000 Today Is Worth More Than $1,000 Next Year (Time Value of Money)
Time value of money is the foundation of all financial decision-making. Here's the concept, the formulas, and the practical decisions it helps you make better.
December 20, 2025 · Finance · 7 min read
The Freelancer's Invoice Guide: Get Paid Faster and More Reliably
What to include on an invoice, how to structure payment terms, and what to do when clients don't pay. From a practitioner perspective, not a template website.
December 20, 2025 · Health · 6 min read
BMI Calculator Guide — What is BMI and What Do the Numbers Mean?
Learn how to calculate BMI, what the number means, and its limitations. Free BMI calculator guide with healthy weight ranges by height.
December 16, 2025 · finance · 7 min read
How to Read Your Credit Report (The Parts That Actually Affect Your Score)
Your credit report has a lot of information. Most of it matters less than you think. Here's what to look at, what to ignore, and what's worth disputing.
December 12, 2025 · Finance · 7 min read
How to Calculate Mortgage Payments — Free Calculator Guide
Calculate your monthly mortgage payment online for free. Understand principal, interest, amortisation, and how to compare mortgage options before buying a home.
December 10, 2025 · Finance · 6 min read
How to Convert Currency Online — Live Exchange Rates Guide 2025
Convert currency online with live exchange rates. This guide explains how currency conversion works, where to find the best rates, and how to avoid hidden fees.
December 2, 2025 · finance · 5 min read
Percentage Calculations You Keep Having to Google (With Actual Examples)
From tipping to discounts to tax to investment returns — the percentage calculations that come up constantly, explained once and actually memorized.
December 1, 2025 · Finance · 7 min read
Loan Amortization Explained: Why Your First Payments Are Almost Pure Interest
Why most of your early loan payments go to interest, how to calculate amortization yourself, and strategies to pay off loans faster.
November 18, 2025 · finance · 8 min read
Every Tax Deduction Freelancers Are Missing (And How to Track Them)
Self-employment tax is brutal. But you can deduct a lot — and most freelancers miss several significant deductions every year. Here's the complete list with actual rules.
November 15, 2025 · Finance · 7 min read
The 50/30/20 Budget Rule: Does It Actually Work?
An honest look at the most popular budgeting framework. When it works, when it doesn't, and how to adapt it to real life that doesn't fit neat percentages.
November 5, 2025 · Finance · 8 min read
Understanding Your Paycheck Deductions (Finally)
Federal tax, state tax, FICA, OASDI — decoded. Why your take-home pay is so much less than your salary, and which deductions you can actually control.
November 4, 2025 · finance · 6 min read
Emergency Funds: The 3-6 Month Rule Is a Starting Point, Not a Rule
Everyone says 'save 3-6 months of expenses.' But 3 months for whom? And expenses meaning what? Here's how to calculate what you actually need.
October 21, 2025 · finance · 6 min read
ROI Explained: How to Actually Calculate It and What People Get Wrong
Return on investment sounds simple — it's not. Here's how to calculate ROI correctly, the variants that matter in different contexts, and the ways the metric gets misused.
October 5, 2025 · Finance · 7 min read
Compound Interest: Why It's Both Your Best Friend and Worst Enemy
A genuinely useful guide to compound interest — how it works, what the math actually means, and how to use it to your advantage in savings and against you in debt.