[GirlGoneGeek]

I found some, not sure how useful:

16 Essential Landscape and Garden Calculators
Easy to use calculators and estimators that are perfect for the pro landscaper, weekend warrior or your next outdoor project. For the price of a nice coffee, carry these proven calculators that will help estimate that next job or project.

Read the reviews!

Aggregate (Mulch, Rock, etc)
Asphalt
Circle Solver
Concrete & Rebar (Rect/Round)
Wood Fence
Lawn Fertilizer
Pavers
Pine Straw
# Plants
Pond Calculator
Grass Seed
Sod
Sq Ft Cost Estimator
Frost Tables

Detailed descriptions:

Aggregate - Calculate tons, cubic yards and cubic feet for a given width, length, thickness, wastage % and density. Densities include over 15 types of rock, sand, dirt, mulch and gravel.

Asphalt - Calculate tons needed for a given width, length and thickness. Also various Asphalt mixing and estimating charts.

Board/Lineal Feet - Calculate board feet and lineal feet for a given thickness, width, length and # of boards.

Brick/Block - Calculate # of bricks or blocks needed for a given wall length and height, wastage % and block type.

Circle Solver - Calculate Area, Diameter or Circumference

Concrete Rectangle - Calculate cubic yards, cubic feet, premixed bags, portland bags and feet of rebar for a given width, length and thickness and rebar spacing.

Concrete Round - Calculate cubic yards, cubic feet, premixed bags and portland bags for a given diameter, height and number of columns.

Fence - Calculate # of pickets, 2x4 rails, 4x4 posts, 2x8 rot boards and 80# concrete bags for a given fence length, section length, picket width and # of rails.

Lawn Fertilizer - Calculate quantity of fertilizer per treatment for a given type of grass, total square feet, % nitrogen in the fertlizer and number of treatments per year.

Pavers - Calculate # of pavers required for a given area length and width, paver size.

Pine Straw - Calculate # of pine straw bales needed for a given total square feet and type of coverage.

Plant - Calculate # of plants needed in a rectangular and triangular grid for a given total square feet and spacing between plants.

Pond - Calculate pond surface area, volume in gallons, liner length, liner width, suggested pump size, marginal stock and ideal stock for a given pond length, width, max depth, avg depth, pump turnover and radius.

Grass Seed - Calculate number of pounds/kg needed for new or existing lawns for a given total square feet and type of grass.

Sod - Calculate # of slabs or rolls and # of pallets needed for a given square footage, length and width of slab or roll and per pallet coverage.

Sq Feet $ Cost - Calculate Total $ for a given length, width and $ per sq ft.

Frost tables for the US and Canada.