For iPhone and iPad
Cut lists that save lumber.
KerfSmart fits your parts on the fewest sheets of plywood and the fewest boards, takes a saw kerf off every cut, and shows you where to mark. The calculator thinks in feet, inches and fractions, just like your tape.
Free to start, with a one-time upgrade to Pro. No ads, no tracking, no accounts. Requires iOS 17 or later. English and Spanish.
Shop math, done the way you measure
Built for woodworkers, carpenters and weekend builders who are tired of converting fractions and guessing how many sheets to buy.
Tape-measure calculator
Type 5 ft 3 ␣ 1/2 in + 2 ft 7 ␣ 3/8 in and get 7' 10 7/8". Add, subtract, multiply and divide lengths; length × length gives square feet, × length again gives board feet. Results round to your precision, down to 1/64", with a + or − marker when the true value is a hair off.
Plywood cut lists Pro
Enter parts, sheet size and how many sheets you have. KerfSmart finds the layout with the fewest sheets using only straight-through cuts you can make with a circular, track or table saw, then numbers each cut in order. Keep grain direction with one switch.
Lumber cut lists Pro
Give each part a length, width and quantity. KerfSmart picks which boards to buy, 1x2 to 1x12 and 6' to 16', for the least waste, with a drawing and numbered rips and crosscuts for every board. Custom rough mode sizes a blank to mill yourself.
Cut to length Pro
List what you need and one stock length. See how many boards to buy and each board to scale with its mark positions and offcut. Kerf and end trim are taken off automatically.
See what you save
Every layout says what it saves against cutting as you go: Saves 1 sheet (about $55). Put your own sheet, board-foot and stock prices in Settings.
Print and share PDFs Pro
A summary page plus one page per sheet or board, with the diagram and a checklist of cuts. Take it to the shop or the lumberyard. Anyone can share a layout as a picture or a project file.
Scan a written list Pro
Snap a photo of your notes. On-device text recognition reads lines like Side 30 x 23 1/4 (2) or 4 @ 34-1/2" x 11 1/4", and you untick anything it got wrong before the parts fill in.
Saved projects Pro
Name a cut list and every edit saves itself. Projects sync through your own private iCloud to every iPhone and iPad on your Apple Account, and open instantly offline.
Saw Guide Pro
Enter the distance from the edge to your cut line and KerfSmart tells you where to clamp the straightedge for your circular saw, on the keep side or the waste side. Measure your saw's offsets once.
Framing tools Pro
Stairs with risers, treads, stringer length and IRC 7¾" / 10" checks. Rafters with rise, run, plumb angle and pitch to degrees. Stud layout marks at 12, 16, 19.2 or 24" on center.
Crown molding and miters
Crown molding, free for everyone: how to cut each piece upside down and nested on the miter saw, for inside and outside corners at any wall angle, with the compound angles for cutting flat. Pro adds frame miters for any number of sides.
More shop tools Pro
Board feet and lumber cost with 4/4 to 8/4 shortcuts, even spacing for balusters and shelves (by count or the 4" rule), diagonal and square check, and arc radius from width and rise.
The calculator
Fractions in, fractions out
No decimal conversions in your head. Every result comes back the way it reads on a tape, with the exact decimal, millimeters, square feet and board feet one tap away.
- Feet, inches and fractions on the keypad, or metric with m and mm
- Rounds to 1/2" down to 1/64", and shows + or − when the true value is a hair over or under
- Ans carries the last result into the next sum: 8' ÷ 3 = then Ans − 1/8" =
- Tap the result for every conversion: decimal inches, decimal feet, mm, m, sq ft, 4×8 sheets, bd ft, cu yd
- History keeps the last 50 answers; tap one to use it again
- Every length field in the app takes any format: 3/32, 2.4mm, 1 1/2", 8'
- Full dark mode and haptics on the keys
Free to start. Pay once for Pro.
No subscription. KerfSmart Pro is a single purchase that unlocks on every device signed in to the same Apple Account, and Family Sharing is included.
Free
The calculator and more, no purchase needed
- The full tape-measure calculator with conversions and history
- Imperial or metric, your choice of fraction precision
- Crown molding tool
- Plywood preview: enter your parts and see how many sheets you need and what Pro would save
- Scan a written list and see what was read
- Share layouts as a picture or a
.kerfsmartproject file - Open project files from Messages, Mail, AirDrop or Files
Pro One-time purchase
Everything in Free, plus:
- Cut to lengthHow many boards to buy and where to mark each cut.
- Plywood cut listsParts on the fewest sheets with numbered, step-by-step cuts.
- Lumber cut listsWhich boards to buy for the least waste, with rips and crosscuts drawn.
- Print and share PDFsTake the plan to the shop or the lumberyard.
- Scan written cut listsSnap a photo of your notes and the parts fill in.
- Saved projectsName and save your cut lists, synced through your private iCloud.
- Every shop toolBoard feet, spacing, stairs, rafters, stud layout, miters, diagonals, arcs.
- Saw GuideWhere to clamp your straightedge for a circular saw cut.
- Your shop name on shared plansPut your name at the top of shared pictures, without the KerfSmart line.
Payment is charged to your Apple Account. Everything you've already entered stays yours whether or not you upgrade, and you can restore your purchase on a new device from Settings → KerfSmart Pro → Restore Purchases.
Before you cut
KerfSmart helps with shop math. The saw, the material and the building code are still yours to check.
Measure twice
KerfSmart does the math, but it can only be as accurate as what you enter. Check results against your actual material before you cut.
Not professional advice
Stair, rafter and other framing results are estimates for planning. They are not engineering, architectural or code-compliance advice. Check local codes and use a qualified professional for structural work.
Work safely
Follow your tool manufacturer's instructions, wear eye and hearing protection, and keep guards in place. You are responsible for how you use your tools and materials.
Provided as is
KerfSmart is provided as is, without warranty, under Apple's Standard License Agreement. To the extent the law allows, the developer is not liable for wasted material, damage or injury from using the app. Read the terms.
Private by design
No accounts, no ads, no analytics. The developer never receives your data.
Stays on your device
Settings, prices and calculator history live on your iPhone or iPad. There is nothing to sign up for and no server of ours to send anything to.
Your own iCloud
Saved projects sync through the private iCloud database that belongs to your Apple Account. Only you can see them, and you can turn iCloud off for KerfSmart at any time.
Scanning happens on device
Photos of your notes are read by Apple's on-device text recognition. They are not uploaded anywhere and are not kept after the parts are added.
Questions?
Find answers in the support section or send an email. Every message gets read.
Support
Help with KerfSmart for iPhone and iPad.
Email 33.savings-voyager@icloud.com. Include your device model, iOS version and the app version from Settings, and the parts list if a layout looks wrong. Replies usually take a few days.
Pro and purchases
What's free and what needs Pro?
The calculator, its conversions and history, metric mode, the crown molding tool, sharing layouts as pictures or project files, and a Plywood preview that shows how many sheets you need are free. KerfSmart Pro, a one-time purchase, unlocks the cut-to-length, lumber and plywood cut lists with their diagrams and numbered cuts, PDF printing and sharing, adding scanned parts, saved projects with iCloud sync, the Saw Guide, every tool in the Tools tab, and your shop name on shared pictures.
I bought Pro but it isn't unlocked on my other device
Make sure the device is signed in to the same Apple Account you bought Pro with (or one in the same Family Sharing group), then open Settings in KerfSmart, tap KerfSmart Pro and tap Restore Purchases. You will not be charged again.
Is Pro a subscription?
No. It is a single purchase through Apple's in-app purchase system, with nothing recurring. It stays unlocked on every iPhone and iPad signed in to your Apple Account, and Family Sharing is included.
How do I get a refund?
Apple handles all payments and refunds. Go to reportaproblem.apple.com, sign in with your Apple Account, find KerfSmart Pro and choose Request a refund.
Calculator
How do I type a mixed number like 5' 3 1/2"?
Press 5 ft 3 ␣ 1 / 2 in. The ␣ key separates the whole inches from the fraction. A plain number next to a length is read as inches, so 6 ft + 2 is 6' 2".
What do the + and − after a result mean?
Results are rounded to the precision you picked in Settings (1/2" down to 1/64"). A + means the exact answer is a hair longer than the fraction shown, a − means a hair shorter. Tap the result to see the exact decimal. You can turn the marker off in Settings.
Why did multiplying two lengths give me square feet?
Length × length is an area, so KerfSmart shows square feet, and length × length × length shows board feet and cubic feet. Length ÷ length gives a plain number, which is handy for "how many pieces fit". If you only wanted a plain multiplication, enter the second value without a unit.
How do I switch to metric?
Settings → Units → Metric. The keypad swaps its unit keys to m and mm, and results show as decimals. Every length field also accepts mixed input like 2.4mm or 1 1/2" regardless of the setting.
Cut lists
The layout uses more sheets than I expected
Check the kerf (Settings → Blade kerf, 1/8" by default), the sheet size and quantity, and whether Keep grain direction is on; grain-locked parts can't be turned to fill a gap. Plywood layouts only use straight-through (guillotine) cuts, so that you can actually make them with a circular, track or table saw. If a layout still looks wrong, email the parts list and we'll take a look.
What does "compared with cutting as you go" mean?
The savings line compares KerfSmart's layout with taking the parts in list order and starting a new sheet, board or strip whenever the next part doesn't fit. The dollar figure uses the prices in Settings → Prices (per plywood sheet, per board foot and per stock board), so set those to what you actually pay.
How do I set my saw's kerf and the trim on rough ends?
Settings → Blade kerf sets the width removed by every cut in all three cut lists; most saw blades are 1/8" (about 3 mm), thin-kerf blades about 3/32". In the Length list, End trim removes a little from each end of the stock for rough factory ends.
Which boards does the Lumber list choose from?
Tap the widths (1x2 to 1x12) and lengths (6' to 16') your lumberyard carries and you can haul, and pick 1x, 5/4 or 2x thickness. KerfSmart picks the combination with the least waste, preferring fewer and smaller boards. Custom rough mode instead suggests a single rough-sawn blank within the limits you set, with extra width and length for jointing and planing.
Tips for scanning a written list
Write one part per line with the name first, then the sizes and quantity, for example Side 30 x 23 1/4 (2), 4 @ 34-1/2" x 11 1/4" or Shelf 34½ x 11¼ qty 3. Good light and a flat page help. Review the list before adding and untick anything that was misread.
How do I open a .kerfsmart file someone sent me?
Tap the file in Messages, Mail, AirDrop or Files and choose KerfSmart. The app switches to the right Cut List mode and loads the parts and stock settings. With Pro it is also saved as a new project.
Projects and iCloud
My projects aren't syncing between devices
Make sure each device is signed in to the same Apple Account and that iCloud is turned on for KerfSmart (Settings → your name → iCloud → Saved to iCloud → see all apps). Syncing needs a network connection; projects you make offline sync the next time you're online. The newest edit wins if a project was changed on two devices.
How do I move my projects to a new iPhone?
Sign in to the same Apple Account on the new device, install KerfSmart and open it. Projects download from your private iCloud database. Pro unlocks with Restore Purchases.
How do I delete my data?
Swipe to delete any project in the app; the deletion applies on every device. Deleting the app removes its settings and history from the device. To clear the iCloud copy too, go to Settings → your name → iCloud → Manage Account Storage → KerfSmart → Delete Data.
Tools
Why does the stair tool flag my riser height?
It checks against the common residential code limits of a 7¾" maximum riser and a 10" minimum tread (IRC). You can change the limits in Settings. Codes vary by location, so confirm with your local building department before you build.
How does the Saw Guide know where to clamp?
You measure your circular saw once: the distance from the blade to the narrow side of the base plate and to the wide side. Settings keeps both (1½" and 4½" by default). Enter the distance from the board's edge to your cut line, say whether the straightedge goes on the keep side or the waste side, and the Saw Guide gives the clamp position.
Is KerfSmart available in Spanish?
Yes. The app follows your iPhone's language. To use Spanish only for KerfSmart, go to Settings → Apps → KerfSmart → Language.
Safety
Privacy Policy
Effective November 6, 2026
Who we are
KerfSmart ("the App") is published by Dylan McCaffrey ("we", "us"). Contact: 33.savings-voyager@icloud.com.
Information you enter
You may enter part names and sizes, stock sizes, prices, a shop name, calculator entries and settings such as units, precision and blade kerf. This information is stored:
- On your device, protected by iOS data protection, and
- In your private iCloud database (Apple CloudKit) for saved projects, if you're signed in to iCloud and have KerfSmart Pro, so they can sync to your other devices and be restored.
Your private iCloud database belongs to your Apple Account. We have no access to it. Apple handles iCloud data under Apple's Privacy Policy.
What we collect
Nothing. The App has no accounts, servers, analytics, advertising, tracking or third-party SDKs. We don't receive, store, sell or share any personal information. This website is a static page with no cookies or analytics of ours; it is served by Cloudflare, which may log requests to operate the service under Cloudflare's Privacy Policy.
Permissions
- Camera and Photos: used only when you choose to scan a written cut list. The photo is read by Apple's on-device text recognition (Vision). It is not uploaded anywhere and is not kept by the App after the parts are added.
The App does not ask for your location, contacts, microphone or notifications.
Purchases
KerfSmart Pro is sold through Apple's in-app purchase system. Apple processes the payment and we receive no name, payment details or other personal information. Your purchase is tied to your Apple Account and can be restored from Settings in the App.
Shared files
If you share a layout as a picture, PDF or .kerfsmart project file, the file is created on your device and goes only where you choose to send it. It contains the parts, sizes and settings of that list and, if you entered one, your shop name. Shared pictures without Pro also carry a "Made with KerfSmart" line and an App Store link.
Your control
You can edit or delete any project, history entry or setting in the App at any time. Deleting the App removes its data from your device. To remove the iCloud copy, go to Settings → your name → iCloud → Manage Account Storage → KerfSmart → Delete Data.
Children
The App isn't directed at children under 13 and collects no information from anyone.
Changes
If this policy changes, we'll update this page and the effective date above.
Contact
Questions? Email 33.savings-voyager@icloud.com.
↑ Back to topTerms of Use
Effective November 6, 2026
Agreement
KerfSmart is licensed to you under Apple's Licensed Application End User License Agreement (the "Standard EULA"). These terms add to it. If they conflict, the Standard EULA controls. By installing or using the App you accept both.
What the App is for
KerfSmart is a calculator and planning aid for woodworking and carpentry. It computes measurements, cut layouts and reference figures from the numbers you enter. It does not inspect your material, your tools or your site.
Measure twice
Results can only be as accurate as what you enter, and real material varies: sheets are not always a full 96" × 48", boards are not always straight, and blades differ in kerf. You are responsible for checking every measurement and layout against your actual material before cutting, and for any cuts you make.
Not professional advice
Stair, rafter, stud layout and other framing results are estimates for planning. They are not engineering, architectural, construction or code-compliance advice, and the code checks in the App reflect common limits that may not apply where you live. Building codes vary by location. Confirm requirements with your local building department, and have structural work designed, built or inspected by a qualified professional.
Work safely
Power tools can cause serious injury. Follow your tool manufacturer's instructions, wear eye and hearing protection, keep guards in place and use appropriate work-holding. The Saw Guide and cut instructions describe where to measure and cut; how you operate your tools is your responsibility.
Provided as is
The App is provided "as is" and "as available", without warranty of any kind, express or implied, including fitness for a particular purpose and accuracy of results. To the fullest extent permitted by law, the developer is not liable for wasted or damaged material, extra cost, property damage, injury, or any indirect, incidental or consequential loss arising from use of the App or reliance on its results. Where liability can't be excluded, it is limited to the amount you paid for the App in the twelve months before the claim.
KerfSmart Pro
KerfSmart Pro is a one-time, non-consumable in-app purchase processed by Apple and subject to Apple's terms. It unlocks on devices signed in to the same Apple Account and, where enabled, through Family Sharing. Refunds are handled by Apple at reportaproblem.apple.com. Features included in Pro may change over time as the App is updated.
Your content
You own what you enter and the files you share from the App. Shared pictures made without Pro include a "Made with KerfSmart" line and link. You are responsible for anything you share and for having the right to share it.
Intellectual property
The App, its design, text and code are owned by the developer. You may not copy, modify, reverse engineer or redistribute the App except as the Standard EULA or applicable law allows.
Changes
These terms may be updated from time to time. The current version is always on this page with the date above. Continuing to use the App after a change means you accept the new terms.
Contact
Questions about these terms? Email 33.savings-voyager@icloud.com.
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