Free Debt Calculators for Your Website
All eight calculators are free to embed. No signup, no API key, no fee, no attribution required. Paste one iframe and your readers can see that $6,000 at 22.15% costs $9,416.37 in interest over 212 months at the minimum payment.
Last updated August 30, 2026
Each calculator is mobile-friendly, loads in its own iframe so it cannot slow your page, and was built by Dr. James Frederick Smiling, PhD in Mathematics Education from NC State University. Nothing your readers type is stored or sent anywhere. The math runs in their browser and stays there.
The rate above is not an illustration. The Federal Reserve G.19 release put the average APR on credit card accounts assessed interest at 22.15% in the second quarter of 2026, up from 21.52% in the first quarter. That is the number behind every default your readers will see.
Which Calculator Should You Embed on Which Page?
Match the tool to the question the page already answers. A reader who arrived asking one thing will not use a calculator that answers a different one.
| Calculator | The question it answers | Best on a page about |
|---|---|---|
| Credit Card Payoff | When is this card gone, and at what cost? | Credit card debt, minimum payments |
| Snowball vs Avalanche | Which payoff order saves more? | Multiple debts, payoff strategy |
| Loan Extra Payment | What does $100 more a month buy me? | Personal and auto loans |
| Debt Consolidation | Does consolidating actually save money? | Consolidation loans, balance transfers |
| Student Loan Planner | How long until these loans are done? | Student loan repayment |
| Mortgage Payoff | What does paying early really save? | Mortgages, refinancing |
How Do You Embed a Debt Calculator on Your Site?
Four steps, and the whole thing takes under five minutes.
- Pick the calculator below that matches your page, using the table above if you are unsure.
- Click Copy Code to put the iframe on your clipboard.
- Paste it into your page wherever an HTML or custom-code block is allowed. WordPress, Squarespace, Webflow, Ghost and plain HTML all accept it as is.
- Load the page on a phone and confirm the calculator fits the screen. The iframe is responsive, but your own container may need a width of 100%.
What Attribution Do We Ask For?
If you embed a calculator, we ask that you include a visible credit link near the tool so your readers know where the math came from. That is the only requirement, no fees, no signup, no API keys.
Suggested attribution (copy-paste)
If you write a longer article and want to mention us in the body copy, please link to our About page or one of the relevant calculator pages instead of the homepage. Deeper links are more useful to readers and to us.
How Accurate Is the Math Behind These Calculators?
These calculators were built by Dr. James Frederick Smiling, Ph.D., Mathematics Education Professor at the University of North Carolina at Pembroke, with a doctorate in STEM-Mathematics Education from NC State University.
Every result uses the same standard amortization formulas a bank or financial advisor would use, with monthly compounding and the simple interest formula I = P × r × t applied per-period. Snowball and avalanche calculations process each debt’s payoff order using the exact algorithms described in personal finance textbooks, not rough estimates or rounded approximations.
What that means for your readers: the payoff date, total interest, and savings figures they see are the same numbers they would calculate by hand with the right formulas. Free, accurate, and trustworthy.
What Do Publishers Ask Before Embedding?
Is there really no cost?
No cost. No paywall. No ads inside the calculator widget. We earn from paid mini-guides on our own site, not from embeds.
Will the embed slow down my page?
Each calculator loads in an iframe and is independent of the JavaScript on your page. The widget itself is lightweight (no heavy libraries) and is served from a fast CDN. Most pages should see no measurable impact on Core Web Vitals.
Can I customize the colors or layout?
Not at this time, the calculators ship with a consistent design so your readers get a tool that looks and behaves the same as the original. If you have a strong customization need, email us and we will see what we can do.
Can I use these on a paid course, paid newsletter, or client portal?
Yes, provided the calculator itself stays free to the end user and the attribution link is visible. We just ask that you do not repackage or resell the tool itself.
Will the calculations stay accurate over time?
Yes. The math behind amortization does not change. If we ever update the underlying logic, your embedded iframe will pick up the change automatically, you do not have to re-copy anything.
Do my readers have to sign up or hand over any data?
No. There is no signup, no email gate and no account. Every figure a reader types stays in their own browser and is never transmitted to us or to anyone else, so you are not passing your audience through a lead capture you did not choose.
I have a question that is not listed here.
Email hello@debtclaritytools.com with “Embed question” in the subject line. We respond within 1-2 business days.