Feet & Inches Calculator
A running tape for measurement arithmetic: type entries the way they are written on the tape — 5' 6 3/8", 42", 3.5' — and chain +, −, ×, and ÷ with every step computed exactly on the 1/16-inch grid. The total reads in feet-inches-fraction, decimal feet, and metric at once.
Running tape
Example: 5' 6 3/8" + 2' 9 3/4" = 8' 4 1/8" — exact, never a rounding artifact.
Measurement arithmetic only — quantity and geometry estimates across this site carry the same rule: no structural adequacy, code compliance, or engineering; verify dimensions and local code with a professional.
Fraction math without the drift
Tape-measure fractions are all sixteenths in disguise — 1/2 is 8/16, 3/8 is 6/16, 3/4 is 12/16. This tool converts every entry to a whole count of sixteenths and does the arithmetic on those integers: 5' 6 3/8" is 1,062 sixteenths, 2' 9 3/4" is 540, and their sum 1,602 sixteenths reads back as 8' 4 1/8" = 100.125 in = 8.3438 ft = 2,543.175 mm. Adding the decimal forms (66.375 + 33.75) works too — until a chain of conversions leaves a stray thousandth; integer sixteenths cannot drift.
Division is where the tape shines: a wall of 8' 1 1/2" split into three equal bays is exactly 2' 8 1/2" per bay — the kind of layout split that produces ugly repeating decimals in decimal feet.
Feed the result into any estimator
This page is the arithmetic hub for the whole suite — chain your field measurements here, then carry the total into the estimator you need:
- Square Footage Calculator — Add rooms and rectangles, get per-room areas and the combined total in sq ft, sq yd, and sq m.
- Volume Calculator — Box, cylinder, sphere, and cone volumes in cu ft, cu yd, US gallons, m³, and liters — every conversion exact.
- Linear Feet Calculator — Total a cut list of pieces entered as feet and inches (or inches only), with counts and a cost at your price per foot.
- Construction Unit Converter — Length, area, volume, and weight between imperial and metric — exact factors, feet + inches entry, printable chart.
- Stair Calculator — Total rise to riser count, exact riser height snapped to 1/16 in, total run, stringer length, angle, and common-IRC checks.
- Roof Pitch Calculator — Pitch or measured rise/run to slope factor, common and hip/valley rafter lengths, roof angle, area, and squares.
- Board Foot Calculator — Length × width × thickness ÷ 12 per piece, whole-order board feet, and cost at your price per board foot.
- Concrete Slab Calculator — Slab length × width × thickness to cubic yards, with waste and a quarter-yard ready-mix ordering figure.
- Concrete Bag Calculator — One volume compared across 40, 50, 60, and 80 lb bags using manufacturer yield data.
- Brick Calculator — Wall area minus openings, times BIA per-size coverage (joint included) — bricks to buy, with cited mortar bags for standard brick.
- Concrete Block Calculator — Wall area over the nominal 16×8 in CMU face (exactly 0.889 sq ft, joint included), plus waste and cited mortar bag counts.
- Concrete Footing Calculator — Footing length × width × depth × count to cubic feet, yards, and bags — volume for dimensions your plans already set.
- Concrete Column Calculator — Round tube forms (π r² h) or rectangular piers, times the count — exact volume and bag counts, never sizing advice.
- Post Hole Concrete Calculator — Hole cylinder minus the post below grade, times the hole count — bags to set posts, with the 3× guidance labeled.
- Rebar Calculator — Grid bars each way from your spacing, linear feet with lap-splice allowance, and ASTM nominal weight.
- Paver Calculator — Patio area over your paver’s face size, with cutting waste and the sand bedding volume at a depth you control.
- Gravel Calculator — Area × depth to cubic yards, with optional tons at the density your supplier quotes.
- Topsoil Calculator — Footprint × depth to cubic yards of dirt, with optional tons at the density your supplier quotes.
- Mulch Calculator — Bed area × depth to cubic yards and standard 2 cu ft bag counts, with a bulk comparison.
- Sand Calculator — Area × depth to cubic yards of sand, with optional tons at the density your supplier quotes.
- Sod Calculator — Lawn area over your farm’s roll size, with trimming waste — rolls to buy and pallets at your supplier’s count.
- Paint Calculator — Perimeter × height minus openings, times coats, over adjustable coverage — gallons to buy.
- Drywall Calculator — Walls plus optional ceiling minus openings, with waste, over your sheet size — sheets to buy.
- Flooring Calculator — Floor area plus waste to a purchase area, then whole boxes at your box coverage.
- Tile Calculator — Your tile size and grout gap give the real per-tile footprint, then tiles and boxes.
- Wallpaper Calculator — Honest strip-based roll counts: strips cut to whole pattern repeats, whole strips per roll — from your roll’s label dimensions.
- Insulation Calculator — Area to insulate over the coverage printed on your package label, plus cutting waste — batts and rolls to buy.
- Roofing Shingle Calculator — Footprint × a computed pitch factor to true roof area, then squares and shingle bundles.
- Siding Calculator — Walls + gable triangles − openings to siding squares (100 sq ft each) and pieces from your profile’s own spec.
- Fence Calculator — Run ÷ spacing to sections, posts, and rails; pickets from your width + gap; setting concrete via the post-hole math.
- Deck Material Calculator — Joists at your plan’s spacing plus rim, deck boards from width + gap and stock length — quantities, never spans.
Frequently asked questions
Why does this calculator work in sixteenths instead of decimals?
Because tape measures do. Every entry is converted to a whole number of 1/16-inch increments and all arithmetic happens on those whole numbers, so 5' 6 3/8" plus 2' 9 3/4" is exactly 8' 4 1/8" — no 0.0000001 drift, ever. Decimal and metric equivalents are computed from the same exact total for display.
What entry formats are accepted?
The common ways measurements get written: 5' 6 3/8", 5 ft 6 3/8 in, 5'6-3/8", 8'-0", 42, 42", 42in, 3.5', 6 3/8, and 3/8. A bare number is read as inches. Decimals are accepted and converted exactly when they land on a sixteenth (3.5' is 42").
What happens to values finer than 1/16 inch?
They are rounded to the nearest sixteenth and the tape line says so explicitly — for example 1/32" rounds to 1/16" and is marked "(rounded)". The tool never silently absorbs a remainder, so you always know when a figure was adjusted to the tape grid.
How do multiply and divide work on a length?
They scale the running total by a plain number: seven treads at the current length, or a wall split into three equal bays. If the result leaves the 1/16 grid — a third of 100/16, say — it is rounded to the nearest sixteenth and flagged, exactly like fine entries.
Can I convert the result to metric?
The running total always shows millimetres and metres alongside feet-inches and decimal feet, using the exact definition 1 in = 25.4 mm. For standalone conversions in both directions, use the Construction Unit Converter.
Tape figures are computed locally and never transmitted. The exact-fraction contract and the shared pipeline are documented on the methodology page.