If you only use one calculator, use this one
Most stair projects begin with a single measurement — the total floor-to-floor height — and everything else follows from it.
Stair Rise and Run Calculator
Enter your total rise and get riser height, tread depth, step count, stair angle, stringer length, landing requirements and stringer count — checked against IRC residential limits as you type.
Build outputStair Stringer Calculator
Take a finished plan to notch points and a ready-to-cut diagram.
Most "stair calculators" are one page bolted onto a site built for something else
General calculator sites cover thousands of unrelated topics — mortgage payments, BMI, concrete volume — with a single generic stair tool somewhere in the mix. This site does one thing. Here's the concrete difference that makes, not just the claim.
| What you get | Typical general calculator site | mystaircalculator.com |
|---|---|---|
| Stair-specific calculators | 1–3 | 93 |
| Formula shown on the same page as the result | Rarely | Every calculator |
| Exact code section cited (e.g. IRC §R311.7.5.1) | Almost never | Every code-relevant result |
| Landing, headroom & stringer-count checks bundled with rise/run | Separate tools, if they exist at all | Built into the core planner |
| Account or email required to see full results | Sometimes | Never |
| Public log of corrected errors | Not published | Published below |
This compares against generic, multi-topic calculator sites as a category, not any single named competitor — you can verify every row yourself against whichever site you're currently comparing us to.
10 categories, 93 calculators
Every tool on the site falls into one of these. Pick the category closest to what you're planning, or use the search box above if you already know what you need.
Core Geometry & Layout
The flagship cluster — rise, run, riser height, tread depth, angle, headroom and comfort formulas.
IRC caps risers at 7.75" and floors tread depth at 10"Stair Types & Styles
Layout math specific to spiral, winder, L-shaped, U-shaped, floating, deck, basement and outdoor stairs.
Each shape has its own walk-line and headroom logic — not the straight-run formula relabeledStructural & Load Engineering
Stringer spacing, beam span, footing size and load capacity for the parts that carry weight.
Planning-stage math only — not a substitute for a stamped engineering reviewMaterial-Specific Structural
The same structural math, split by build material — concrete, wood, steel, stone, brick and composite.
Wood and steel stringers don't share a spacing formula — this cluster keeps them separate on purposeMaterials, Finishing & Cut-Lists
Surface and trim quantities — carpet, tile, vinyl plank, paint, nosing and skirt board cut lists.
Cut lists account for nosing overhang, so tread count doesn't quietly undercount materialRailing, Baluster & Safety
Everything above the treads — railing runs, baluster spacing, handrail and guardrail height.
ADA 505.10 sets handrail height at 34"–38" above the nosingCode Compliance
Direct code checks against IRC, IBC, ADA and UK Part K — the tools built for permit and plan-check prep.
IBC §1011.5.2 tightens commercial limits to a 7" max riser, 11" min treadCost & Estimating
Installation, remodel, railing and lift cost estimates, plus a labor-vs-material cost split.
Ranges by material and finish tier, not a single flat number that ignores your buildSpecialty & Accessories
Under-stair storage, LED lighting, stair-lift track length, pet ramps and child gate fit.
The long-tail questions a generic calculator site never bothered buildingConversion & Unit Tools
Quick-reference unit and angle converters — inches to mm, angle to slope percent, board feet.
For reading plans drawn in one unit while you're building in anotherPopular calculators across the site
A cross-section of the tools people reach for most, pulled from every category.
Stair Rise and Run Calculator
The full planner — riser, tread, angle, stringer length and code checks from one number.
Stair TypesSpiral Staircase Calculator
Center pole radius, tread rotation and headroom for a tight-footprint spiral run.
Code ComplianceIRC Stair Code Checker
Run any set of riser, tread and headroom numbers straight against IRC residential limits.
Code ComplianceADA Stair Compliance Calculator
Checks a stair or ramp layout against ADA 505 accessibility provisions.
Cost & EstimatingStair Installation Cost Calculator
Ballpark labor and material cost for a new staircase, by material and finish level.
Material-SpecificConcrete Stairs Calculator
Concrete volume, form dimensions and rebar layout for a poured stair.
Railing & SafetyStair Railing Calculator
Railing run length, post spacing and material list from your stair layout.
Stair TypesDeck Stair Calculator
Outdoor stringer layout that accounts for ground slope and open risers.
Core GeometryStair Headroom Calculator
The single most commonly failed code item on basement stairs — check it in isolation.
One measurement in, a full plan out
The same basic workflow runs behind every calculator on the site, whether you're checking a single number or planning an entire staircase.
Pick the calculator that matches your question
Use the category grid or the search box above. Most projects start with Rise and Run, then branch into cost, material or code-specific tools as decisions narrow down.
Enter what you've actually measured
Total rise, available run, stair width — whatever the calculator asks for. Every input field explains exactly what to measure and where, in plain language.
Get results with the math shown, not hidden
Results update instantly, and every calculator shows the formula behind each number — not just an answer to trust blindly.
Read the compliance chips before you cut anything
Where a code limit applies, results are checked against it automatically — green for pass, red for a number to revisit — with the specific code section cited alongside it.
| The 108" example from the calculator above, worked out | |
|---|---|
| Steps needed | 108" ÷ 7.5" target riser ≈ 14 steps |
| Actual riser height | 108" ÷ 14 steps = 7.71" — under IRC's 7.75" max |
| Comfort-formula tread | 2(7.71") + T ≈ 25" → T ≈ 9.6", floored to IRC's 10" min |
| Resulting angle | arctan(7.71 ÷ 10) = 37.6° — top edge of the 30–37° comfort range |
That last row is the point: the tread got floored to stay code-legal, which pushed the angle right to the edge of comfortable. A calculator that only outputs "37.6°" hides that trade-off. One that shows the arithmetic lets you decide whether to widen the stairwell instead.
"Verified" only means something if you can see what it was verified against
Every formula on this site traces back to one of the sources below. Where a figure hasn't been traced to a primary citation, the calculator shows a visible flag instead of presenting an unsourced number as settled fact.
| Standard / source | Used for | Status |
|---|---|---|
| 2021 International Residential Code (IRC), §R311.7 ↗ | Riser, tread, headroom, landing rise limits | Live, cited |
| International Building Code (IBC), §1011.5 ↗ | Commercial stair and egress width limits | Live, cited |
| ADA Standards, §505 & ramp provisions ↗ | Ramp slope, ADA stair compliance checks | Live, cited |
| ICC A117.1 (Accessible and Usable Buildings) ↗ | Accessible route and clearance figures | Live, cited |
| UK Building Regulations, Approved Document K ↗ | Rise, going and pitch limits for a UK stair calculator | In development |
Codes get amended locally, and IRC itself runs on a three-year revision cycle — 2021 is our stated current baseline, not implied as universally current. Always confirm final numbers with your building department before cutting material or filing for a permit. Read the full sourcing tiers and review chain in our Editorial Policy, including a real edge case the process caught, documented on the About Us page.
Sample citations, not just the standard's name
Max riser height
7.75" maximum, the limit every geometry calculator's riser chip checks against.
Min tread depth
10" minimum, floored automatically whenever the comfort formula would go lower.
Headroom clearance
80" minimum measured perpendicular from the nosing line, not straight up.
Handrail height
34"–38" above the nosing, referenced by every railing and ADA calculator.
Commercial riser/tread
7" max riser, 11" min tread — stricter than residential IRC limits.
Accessible stair width
The clear-width figure behind our egress and accessibility width calculators.
Corrections log
Sites that hide their mistakes aren't more accurate — they're just less honest about it. Confirmed errors get logged with what changed, not quietly patched.
The dated corrections log lives in one place: our Editorial Policy. We keep a single canonical record there instead of duplicating it across pages, so it never drifts out of sync with what's actually live. Recent entries include the tread-depth flooring logic on the Stair Rise and Run Calculator, named team bios on About Us, and the Editorial Policy page itself going live.
Found something that looks wrong? Report it with the calculator name and the inputs you used — we re-derive the fix from the source, not just patch the output.
Want the reasoning, not just the calculator?
Our guides walk through comfort formulas, common measuring mistakes, and how code limits interact — the context behind the numbers.