Karl's Mortgage Calculator
Karl's Mortgage Calculator: A free, multi-platform calculator for detailed mortgage scenarios, including Canadian and UK modes. Ranked #23 of 34 in Mortgage Calculator Apps by our editors (7.2/10); pricing: Free plan; best for advanced multi-country mortgage calculations.
At a glance
- Editor score7.2 / 10
- PricingFree plan
- Best forAdvanced multi-country mortgage calculations
- Free planYes
- Amortization scheduleYes
- Facts checked14 Nov 2026
Where it wins
- Reverse-calculate a loan input when the other three are known
- Model adjustable rates, interest-only loans, and extra payments
- Include taxes, insurance, PMI, and HOA costs in payment estimates
Where it doesn't
- Loan estimates depend on the inputs entered
- Separate Pro app is a one-time purchase
- Support is limited to email
Our verdict on Karl's Mortgage Calculator
Karl's Mortgage Calculator helps people calculate and compare mortgage payments across a range of loan structures. It is available on the web, Android, and iOS, with a free plan. The calculator covers core principal, interest rate, and term inputs, and can solve for one when the other three are provided. Its breadth makes it a fit for borrowers or small-scale users who need to examine more than a standard fixed-rate payment; anyone looking for a broader lending or financial-planning suite should look elsewhere.
The standout depth is in scenario modeling. Users can account for adjustable-rate changes, interest-only mortgages, and one-off, monthly, or annual extra payments, then examine payment and amortization results. Taxes, insurance, PMI, and HOA costs can also be included in estimates. The vendor site offers separate affordability and qualification calculators. This combination is useful when comparing loan structures or testing how extra payments and recurring costs affect an estimate, though outputs remain dependent on the assumptions entered.
Regional support is a notable distinction: the calculator supports Canadian mortgages and UK annual-rest mortgages alongside general mortgage calculations. That can suit people comparing scenarios across these conventions, while the web and mobile availability provides several access options. A separate Pro app is available as a one-time purchase, and its price differs between Google Play and the US App Store. Support is offered by email. Choose this calculator for detailed mortgage calculations across supported regions; choose another option if you need a broader financial tool or a single consistent Pro price across those stores.
Your product? Our editors can test Karl's Mortgage Calculator in depth and publish a review, labelled as paid · from $149/mo →
Karl's Mortgage Calculator pricing
Karl's Mortgage Calculator fact sheet
| Free plan | Yes |
|---|---|
| Paid from | Not verified |
| Amortization schedule | Yes |
| Affordability analysis | Yes |
| Refinance scenarios | Not verified |
| ARM calculations | Yes |
| Property-tax inputs | Yes |
| Insurance inputs | Yes |
| Platform access | Multi_platform |
| Deployment | Cloud, Mobile |
| Platforms | Web, Android, iOS |
| Compliance & security | GDPR |
| Support | |
| Built for | Solo, Small business (editorial estimate) |
| Pricing | Free plan |
| Website | drcalculator.com |
| Facts checked | 14 Nov 2026 |
Alternatives to Karl's Mortgage Calculator
- Chase Mortgage CalculatorFree web calculators cover mortgage payments, affordability, refinancing and loan scenarios.9.4
- Bankrate Mortgage CalculatorA free web calculator for detailed mortgage payment and affordability estimates.9.3
- Fannie Mae Mortgage CalculatorA free web calculator with payment breakdowns plus separate affordability and refinance tools.9.2
See all Karl's Mortgage Calculator alternatives →
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Reviewed by iTechGuides Editors · Editorial team · Updated Nov 2026
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