About
Piggyback (80-10-10) splits financing: 80% first mortgage (avoids jumbo if applicable), 10% HELOC/second mortgage, 10% down. Avoids PMI when down is under 20%. Higher second-loan rate but no monthly PMI premium.
The 80-15-5 and 80-20-0 variants exist too. 80-15-5 fits buyers with just 5% down but commands a second-lien rate roughly 1.5-2.5 percentage points above the first mortgage in the 2026 rate environment. The HELOC structure means the 2nd lien is usually variable, indexed to Prime, which sat at 7.5% in early 2026, while a closed-end home equity loan locks the rate but at a higher start. Crossover math: piggyback wins versus PMI when the blended rate plus 2nd-lien interest is below first-mortgage rate plus annual PMI (typically 0.3-1.5% of loan).
Common pitfalls
- Forgetting HELOC reset risk: the variable second can jump 2-3 percentage points in a single Fed cycle, turning a "PMI-saver" into a more expensive product.
- Trapping yourself on a future refinance: refinancing the first mortgage requires the second-lien holder to sign a subordination agreement, which carries a $150-$500 fee and is not guaranteed to be approved.
Formula
Frequently asked questions
How accurate is the Piggyback Loan Calculator?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Piggyback Loan Calculator free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Can I use the Piggyback Loan Calculator on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum.
Does the Piggyback Loan Calculator work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
How do I report a bug or suggest improvement to the Piggyback Loan Calculator?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours.
Can I share results from the Piggyback Loan Calculator?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another piggyback loan tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.
Is the Piggyback Loan Calculator accurate?
The Piggyback Loan Calculator applies the standard formula for piggyback loan. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Piggyback Loan Calculator free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
How to use the Piggyback Loan Calculator
The Piggyback Loan Calculator is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Piggyback Loan-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.