MB-88F Fractional Calculator
Exact RPN fraction calculator
Free · In-App Purchases · Designed for iPad. Not verified for macOS.
Exact fractions — never a rounded-off 0.4999. For the shop, the kitchen, the sewing table, or homework, with the RPN precision engineers swear by.
MB 88F is a calculator that thinks in exact fractions.
Every value is kept as a whole-number numerator over a whole-number denominator, so the math never drifts. 1/3 + 1/6 is exactly 1/2, never 0.4999. Whether you're cutting a board, scaling a recipe, piecing a quilt, or checking fraction homework, the answer stays exact — and inches and millimeters relate by the exact definition 1 in = 25.4 mm, so conversions never lose a thousandth.
NEW TO RPN?
MB 88F uses Reverse Polish Notation: you key the numbers first, then the operation — 3, ENTER, 4, + instead of 3 + 4 =. No equals key, no parentheses to juggle. It's the input style engineers and HP-calculator fans have sworn by for decades because it makes real calculations flow. If it's new to you, it clicks in about a minute, and a built-in manual, key index, and cheat sheet are right there to walk you through it.
WHAT IT DOES
• Exact fraction arithmetic — add, subtract, multiply, divide, always reduced to lowest terms
• Mixed-number entry: key 2 SPC 1 b/c 2 for 2 1/2
• Tape-measure rounding to 1/8, 1/16, 1/32, or 1/64 — and TRU to restore the exact value
• Fraction ↔ decimal conversion both ways
• Exact unit tagging and conversion: inches, feet, millimeters, meters
• Feet read as feet plus fractional inches (22.5 ft → 22 ft 6 in)
POWER KEYS
• 1/x, x², and √x for diagonals and right-triangle math
• ½x to instantly find a centerline, 2x to double it
• Store/recall memory (STO/RCL) to hold and reuse a value
• History tape — tap the display to see your last 100 results and pull any of them back into the stack
• Last-X recall, stack roll, and swap
MADE TO LIVE WHERE YOU WORK
• Universal — one app, built for both iPhone and iPad
• Your stack, memory, and history are saved between sessions — pick up right where you left off
• 11 color themes
• Optional thousands separator and fixed decimal places
• Built-in user manual, key index, and cheat sheet
• Works 100% offline. No account, no ads, no tracking, no data collected — ever.
Try it free for 2 days, then unlock the full app forever with a single one-time purchase — no subscription.
Woodworkers, machinists, carpenters, and framers rely on it — and so do quilters and sewists, cooks scaling recipes, students working through fraction homework, and anyone who'd simply rather see 3/4 than 0.75. If you think in fractions, MB 88F keeps them exact.
Ratings & Reviews
- This app has not received enough ratings or reviews to display an overview.
• iPad support — MB 88F is now a universal app with a layout built for the big screen
• History tape: tap the display to see your last 100 results, and tap any line to pull it right back into the stack
• Your work now survives relaunch — the stack, memory register, and history are saved automatically
• Tap a value's active unit key to remove the tag and go back to a plain number
• Reliability improvements under the hood
The developer, Maxwell Bayman, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Provider
- Maxwell Bayman
- Size
- 973.8 KB
- Category
- Utilities
- Compatibility
Requires iOS 16.0 or later.
- iPhone
Requires iOS 16.0 or later. - iPad
Requires iPadOS 16.0 or later. - Mac
Requires macOS 13.0 or later and a Mac with Apple M1 chip or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- In-App Purchases
Yes
- Full Version USD 3.99
- Copyright
- © 2026 Maxy McMaxFace, LLC