An adjustable concrete form brace includes a horizontal adaptable extension member. A first lower brace element and a second lower brace element opposing the first lower brace element each have a horizontal insertion channel adapted to receive the horizontal extension member. A first upper brace element and second upper brace element are attached to the first lower brace element and the second lower brace element respectively. Each of the lower brace members include a saddle, and each saddle is adapted to retain one or more reinforcement bars. The first upper brace element and second upper brace element each include a form retaining element.