Dirtwright Sitework Calculator

Dirtwright is a sitework calculator for excavation operators, grade checkers, pipe crews shooting grade, surveyors' helpers, landscapers and civil students. It works like a hardware calculator: an ochre chassis the colour of a fresh trench wall, real keys and a clear LCD, with each answer labelled so you know what you are reading.

LEVELING
• Differential leveling in decimal feet or metres: benchmark, backsight and foresight rod readings give the height of instrument and the ground elevation (benchmark 100, backsight 4.52, foresight 6.31: elevation 98.21)
• A backsight after a foresight is a turning point: the last point becomes the new benchmark, flagged HI AFTER TURN
• Type a known spot elevation or an instrument height directly

GRADE CHECKING
• Design grade against existing ground: CUT, FILL or ON GRADE and the difference (ground 98.21 against a 98.50 grade: FILL 0.29)
• Grade rod: the reading the rod must show at design grade (6.02 in that example)
• Or type the rod reading at a finished stake and the design grade comes back

SLOPES
• Slope from rise and run, or type it as a percent, in degrees, as a pitch (x:12) or as a ratio (rise 2 over run 50 is 4 %)
• Repeat presses cycle percent, ratio (25:1, horizontal to vertical; in metric it reads 1:25, vertical to horizontal), degrees (2.29°) and inches per foot (0.48), or millimetres per metre
• Run from rise and slope, rise from run and slope
• Type a ratio such as 4 for 4:1 (1:4 in metric) and get the slope (25 %)

EARTHWORK
• Length, width and depth, or an area and a depth, give the bank volume in cubic yards or cubic metres (100 × 3 × 5 ft: 55.56 cu yd)
• Volume = area × depth, for one uniform depth with vertical sides, as in a trench or a level cut; work side slopes or a changing depth in parts
• Loose volume with swell and compacted volume with shrink, from the bank volume or from either one typed: 69.44 loose and 50 compacted at the default 25 % swell and 10 % shrink
• Defaults are flagged so you see why, and you set your own; blasted rock can take a negative shrink
• Truck loads by volume, from the loose volume and the load capacity (12 cu yd: 6 loads); check the weight limit too, as dense clay or rock reaches legal weight before the body is full

STATIONS
• Stationing as 12+50.00 in feet or 1+250.000 in metres, from the distance along the line
• Type each station just before or just after its foresight and it takes that ground elevation
• Two stations give the distance between them, the grade in percent and the rise, signed along increasing stationing (625 ft apart, 0.50 %)

WORKS THE WAY YOU DO
• Decimal feet and cubic yards, or metres and cubic metres
• Feet-and-inch entry still works: 4 ft 6 in reads back as 4.50
• A results strip shows every solved value at once
• 10 memories, a tape of your calculations, reference tables (slope conversions, typical swell and shrink, decimal feet to feet and inches) and a key guide
• Export a job strip: the tape with inputs, stamped and ready to attach to a lift plan, sign-off or take-off, as text or PDF

FREE TO TRY, THEN UNLOCK ONCE
Free to try: every feature for 7 days. Then unlock Pro once — no subscription, no ads, works offline.

PRIVATE BY DESIGN
Works offline, no account, no data collected.

How it's calculated: the formulas and tables behind every result, at https://wrightcalc.app/dirtwright/

Questions or feedback: [email protected]

FOR PLANNING AND CHECKING ONLY. Dirtwright is not a substitute for a survey: verify every result against the plans and your instrument. Swell and shrink factors are typical values and vary with the material and the compaction. The developer accepts no liability for loss, damage or injury arising from use.