5.75" x 2.25".
I bought this for an older Schrade multi-tool, 1 1/2" wide x 4 7/8" long x 3/4" thick. My multi-tool fits just fine, although the flap is a little long (so not as much of the velcro matches up). The Schrade one was about 15 years old and made of heavier nylon. This sheath is lighter, won't last as long probably and was a little expensive with shipping (I might've been able to order several and distribute the shipping if I had known my Schrade would fit). The belt loop looks pretty tough though. Single stitching with a little padding. Looked all over and couldn't find anything else that would fit, so I guess I have to like it for now!