In addition, on today's call, non-GAAP financial measures, including adjusted earnings per diluted share, adjusted operating income, constant currency organic revenue growth, and free cash flow will be used. Constant currency organic revenue grew 6% in the quarter, driven by volume as well as 190 basis points of price. Gross margin for the quarter was 46%, up 70 basis points versus the prior year. Margin expansion was driven by price and favorable productivity, which were somewhat offset by inflation.
For clarity, tariff refunds are not being allocated to our business segments, but instead are booked in corporate to enable business segment analysis. EBIT margin for the quarter was 23.8% of revenue, an increase of 100 basis points versus the first quarter of last year. The gross margin improvement, coupled with favorable currency and operating cost discipline, drove the EBIT margin expansion in the quarter. The adjusted effective tax rate in the quarter was 25.9%, an increase of 23.5% in the first quarter of last year.
Earnings per diluted share were $2.59, an 11% increase over the prior year. Capital expenditures for the quarter were $87.5 million, and depreciation in amortization totaled $123.8 million. Gross debt to EBITDA at quarter end was approximately 1.1x, well below our targets of 2x to 2.5x. Free cash flow for the quarter was $279.6 million, down from $326.5 million in the first quarter last year.