Inputs stay visible
Use familiar units and see the input context beside the output. No hidden conversions.
civil engineering, made practical
Quick checks for the work between the big calculations.
Clear, metric-first tools for students, site engineers, and designers who need a sensible answer before opening a spreadsheet.
01Transparent formulas
02Useful assumptions
03Results you can print
LIVE TOOL / SI UNITS
READY
MAXIMUM MOMENT
51.0 kN·m
✦Built for the everyday decisions that sit between a rule of thumb and a full design check.
toolbox / start here
Choose the check in front of you.
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a better engineering reference
Simple enough to use. Honest enough to check.
Every result is paired with the equation, units, and assumptions that produced it. That makes CivilKit a quick starting point—not a black box.
Explore the reference notesAssumptions are part of the result
Boundary conditions and quick-check limits are written into each tool, not buried in a footer.
Useful on site and at your desk
Responsive layouts, printable outputs, and no account wall for the basic calculation.
reference / field notes
The context around the number.
STRUCTURAL5 min read
What does a beam quick check actually tell you?
Moment, shear, and elastic deflection answer different questions. Keep the screening result separate from a complete member design.
Read with the beam toolSTRUCTURAL / REINFORCED CONCRETE5 min read
How do you estimate RC beam flexural capacity?
A visible tension force, compression block, and factor basis make a preliminary reinforced-concrete capacity screen easier to audit.
Read the field noteSTRUCTURAL / REINFORCED CONCRETE5 min read
How do you estimate required RC beam steel?
An inverse stress-block equation estimates theoretical tension-steel area before code checks and a constructible bar arrangement.
Read the field noteSTRUCTURAL / COLUMNS4 min read
What does an Euler column check assume?
Effective length, flexural stiffness, and weak-axis slenderness make ideal elastic instability visible before a full code check.
Read the field noteSTRUCTURAL / GEOMETRY3 min read
What changes when the section is circular?
A solid circle has the same centroidal properties about any diameter, but its diameter-to-property relationship is different from a rectangle.
Read the field noteSTRUCTURAL / GEOMETRY4 min read
Why do I-sections have different strong and weak axes?
Flange width and overall depth distribute area very differently about the two centroidal axes, so Ix, Iy, Zx, and Zy must stay paired with the correct direction.
Read the field noteMATERIALS3 min read
Concrete order quantities: where does the allowance go?
Separate geometric volume from the quantity you order, then record the waste allowance so the decision is easy to audit.
Try the concrete toolUNITS2 min read
Keep the unit system consistent before you calculate.
A quick conversion before a formula is usually cheaper than debugging a result after the fact.
Open the converterHYDRAULICS4 min read
What Manning flow assumes about a channel.
Rectangular geometry, roughness, slope, and uniform flow are useful first-pass inputs—but not the whole water problem.
Read the field noteHYDRAULICS5 min read
How do you solve for Manning normal depth?
A target discharge can be converted into a rectangular-channel depth by iterating the Manning relationship, then checking velocity and flow regime.
Read the field noteHYDRAULICS / CLOSED CONDUITS4 min read
How do you size a full-flow pipe with Manning?
The inverse full-pipe relationship turns target flow, slope, and roughness into an internal diameter estimate before commercial-size and partial-flow checks.
Read the field noteHYDRAULICS4 min read
What does a trapezoidal Manning check assume?
Side slopes change area, wetted perimeter, and hydraulic radius; freeboard and non-uniform flow still need checking.
Read the field noteHYDRAULICS4 min read
What does a full-pipe Manning capacity assume?
Full circular geometry gives a quick capacity estimate, but partial flow, inlet control, tailwater, and head losses still need checking.
Read the field noteHYDRAULICS5 min read
Why does pipe depth change the Manning result?
Partial flow changes area, wetted perimeter, hydraulic radius, and capacity; a full-pipe shortcut is not valid at every depth.
Read the field noteHYDROSTATICS4 min read
Where does hydrostatic wall thrust act?
A triangular pressure diagram gives a base pressure, a resultant thrust, and a centre of pressure at one-third of the water depth.
Read the field noteFOUNDATIONS4 min read
Average footing pressure is only one foundation check.
Compare a concentric screening pressure with an allowable value, then keep eccentricity, settlement, and structural checks visible.
Read the field noteRETAINING WALLS5 min read
Active earth pressure is a wall-movement assumption.
Rankine thrust is a useful first screen for dry level backfill, but water, compaction, stability, and wall stiffness still matter.
Read the field noteFOUNDATIONS5 min read
What does a Terzaghi bearing-capacity screen show?
Separate cohesion, overburden, and soil-wedge terms before comparing gross applied pressure with a preliminary allowable value.
Read the field noteRETAINING WALLS5 min read
What does a simple wall stability screen compare?
Overturning, sliding, resultant location, and linear base pressure provide a first pass before the full wall and foundation design.
Read the field noteLOAD TAKE-OFF4 min read
Turn a floor load into a beam line load.
Keep self-weight, finishes, partitions, live load, and tributary width visible before the beam check.
Read the field noteEARTHWORK4 min read
Average end area is a quantity method, not a soil factor.
Separate in-situ volume from planning allowance, then document bulking, shrinkage, and compaction separately.
Read the field noteSITE / GRADES3 min read
Grade percentage and slope ratio are the same geometry.
Keep vertical change, horizontal run, sign convention, and the chosen design limit visible before setting out a grade.
Read the field noteSTORMWATER4 min read
What does a Rational Method peak flow assume?
Runoff coefficient, design intensity, and catchment area frame a peak flow—but not routing, storage, or inlet design.
Read the field noteCOLUMNS4 min read
What does a gross column stress screen leave out?
Average axial stress is a starting point; slenderness, eccentricity, reinforcement, and code resistance still need separate checks.
Read the field notebuild the habit