Very few online calculators are geared to VA loans, but the calculation is really quite simple. FWIW, rarely do we seen anyone right at 41%......unless they have prior credit issues or other challenges.
For most buyers, the following can be used:
Gross Monthly Income x .44% = max mortage payment and all monthly debts.
From that number, subtract all montly obligations (loans, credit cards, child support) which = max available for PITI
From that number, subtract your estimated real estate taxes, hazard insurance, and HOA, which = max available for P&I
Take that number and divide it by the factor for the current interest rate. You can use anyone's mortgage factor tables, I happen to like this chart when away from my desk:
Amortization Chart
So, let's say by the time you did the math, you were left with $1100. Look at the chart and find the factor for 3.25% for a 30 year loan (4.631). The factor is per 1000, so I skip a step and convert it to .004631). Take the 1100 and divide by .004631 (or you could divide by 4.631 and take the answer and multilply it by 1000.). Your answer is 237K (and change). That loan amount includes your funding fee, so depending on what yours is, you may have to multiply that loan amount by 96.6% (if you are a 2nd time user) or 97.85% for a first time user.