The short answer
NerdWallet and SmartAsset both make excellent, free calculators, and for a full US mortgage estimate with property tax, insurance and PMI they are the better fit. Calc Garden is the better fit when you want the core number fast with no account, no advertising and no lead form. The genuine differentiator is not price, because all three are free. It is the absence of the funnel: NerdWallet monetises through ads and lender referrals, SmartAsset through matching you with a paid financial advisor, and Calc Garden through neither.
How the three compare
The table below lays out the capabilities side by side. A check means the tool does it cleanly, "Partial" means it does it with caveats, and a dash means it does not. The pricing row reflects each product as of 2026.
| Capability | Calc Garden | NerdWallet | SmartAsset |
|---|---|---|---|
| Use core calculators free | Yes | Yes | Yes |
| Price (as of 2026) | $0, no signup | $0, ad-supported | $0, lead-funded |
| No account or email required | Yes | Partial | Partial |
| No ads on the calculator | Yes | No | Partial |
| No lender quote or advisor funnel | Yes | No | No |
| Inputs stay in your browser | Yes | Partial | Partial |
| Shows the formula used | Yes | Partial | Partial |
| US property tax, insurance and PMI fields | No | Yes | Yes |
| State-by-state mortgage data | No | Yes | Yes |
| Editorial guides next to the tool | Yes | Yes | Yes |
Read that table honestly: NerdWallet and SmartAsset win on depth and US localisation, and they are free to use. Calc Garden wins on the things that depth costs you, which are speed, a clean page with no quote prompts, and the certainty that the numbers you type are not feeding a lead system.
Where NerdWallet and SmartAsset are the better choice
Pick one of the bigger sites when you need the full picture of a US home purchase. NerdWallet's mortgage calculator handles down payment, property tax, homeowners insurance, HOA fees and PMI, and it has state-specific versions for places like California, Florida and New York. SmartAsset layers in local insurance and real estate tax data and offers a home affordability calculator and a closing cost calculator alongside its free advisor matching. If your question is "what will my full monthly payment be in this state, including escrow", those tools answer it better than a single-purpose calculator can.
Where Calc Garden is the better choice
Pick Calc Garden when you want one number without the surrounding machine. Our mortgage repayment calculator shows your monthly payment, the total you will repay and, crucially, the total interest over the term, with no fields you do not need. If you want to see how each payment splits between principal and interest year by year, the loan amortization calculator breaks it down, and the FIRE retirement calculator projects long-horizon savings. None of them ask for an email, show an ad, or pass your figures anywhere.
A note on scope: Calc Garden's finance tools are currency-flexible and the mortgage calculator is built for the cost of the loan itself, not a US escrow breakdown. If you need US-specific tax and insurance modelling, that is the one place where reaching for NerdWallet or SmartAsset is the right call.
The honest summary
There is no "only free one" here, and we will not pretend otherwise. All three are free. If you want depth and US localisation, the big sites earn their place. If you want a fast, private, no-signup answer with the formula shown, that is exactly what Calc Garden is built for. For the maths behind the numbers, see our guides, including the best free mortgage calculator that shows total interest.