Flowbox vs Pipe Offset Calc
Price, ratings, monetisation and update history for both apps, side by side β with what reviewers say about each.
Flowbox
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Flowbox is a professional toolkit for plumbers β job-site calculators covering drainage, venting, water supply, gas piping, and pipe fitting, all on-device with no account required. PIPE FUNDAMENTALS β’ Pipe Slope β solve rise, run, or grade against IPC minimums β’ Pipe Offset β travel and run for 45Β°, 22.5Β°, 60Β°, and other fittings β’ Flow Rate & Pressure Drop β Hazen-Williams friction loss for water pipe runs β’ Pipe Volume β water capacity of a pipe segment from ID and length DRAINAGE & VENTING β’ Drain Sizing β minimum drain pipe size from fixture unit load (DFU) β’ Vent Sizing β vent pipe diameter from DFU load and developed length β’ Sump/Ejector Pump Sizing β total dynamic head and horsepower from inflow and lift β’ Grease Trap Sizing β interceptor capacity from kitchen fixture flow rate SUPPLY & GAS β’ Water Supply Sizing β distribution pipe size from fixture unit demand (WSFU) β’ Gas Pipe Sizing β pipe size from BTU load and length, longest-length method β’ Water Heater Sizing β first hour rating or tankless GPM from peak demand β’ Water Hammer Arrestor β PDI-WH201 size from branch fixture units β’ Thermal Expansion β pipe growth and expansion loop size by material WHY FLOWBOX Pro unlock is a one-time purchase β no subscription, ever. No ads. No server required to use any calculator. Free tools (Pipe Slope, Drain Sizing, Pipe Volume) cover everyday use; Pro unlocks the full set. An optional Pro feature lets you sync your saved calculations and projects across your own devices via your own iCloud or Google Drive β off by default, and your data never touches our servers because we don't have any. Flowbox is a reference tool for estimating β always verify pipe slope, drain and vent sizing, water supply sizing, and gas pipe sizing against your local plumbing code (IPC or UPC as adopted locally) and a licensed professional before cutting, sizing, or installing. Gas piping in particular carries real safety consequences if undersized or misrouted.
Pipe Offset Calc
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A pipefitter's offset calculator. One-time purchase β no subscription, no ads, no accounts. Enter an offset and a fitting angle and get travel, run and the cut length, with a drawing that redraws as you type β so a mistyped number shows up as a wrong shape before it becomes a wrong cut. FREE Β· Simple offsets at 11ΒΌ, 22Β½, 30, 45, 60 and 90 degrees Β· Grade and fall β percent and inches per foot Β· Feet-inch-fractions: type 12'6-3/8" the way you write it, or millimetres Β· The live drawing, in every mode UNLOCK ONCE Β· Rolling offsets β set and roll in, true offset, travel, and the roll angle to turn the fitting to Β· Take-outs β cut length with both fittings subtracted, from ASME B16.9 elbow tables Β· Measure your own fitting and save it, for the angles no standard tabulates Β· Pipe data β steel schedule 40 and 80, outside diameter, wall, inside diameter WHERE THE NUMBERS COME FROM The geometry is verified two ways: published trade multipliers, and a check that rebuilds each offset as 3-D coordinates and measures it without using trigonometry at all β so it cannot share a wrong assumption with the formula it checks. Take-outs are a published table cross-checked against two independent references. Every table names its source inside the app. BUILT FOR THE JOB Works with no signal. No account, no sign-in, nothing to lose in a plant room. Glove-sized keys, a fraction key, and a backspace rather than a clear-all. Full VoiceOver support and text that scales to the largest accessibility size.
Screenshots
Verdict
The clearest difference is update cadence: Pipe Offset Calc at every 5 days against Flowbox's every 2 months. Flowbox's advantage is iOS requirement (13.0 vs 15.1). On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price Β· Rating Β· Positive reviews Β· Number of ratings Β· Update frequency Β· Ads Β· In-app purchases Β· Monetization Β· Best chart rank Β· Devices Β· Requires iOS
Both are free to download. Flowbox sells 1 one-off in-app purchase and Pipe Offset Calc sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
Flowbox ships an update every 2 months, Pipe Offset Calc every 5 days. The most recent releases landed on November 6, 2026 and November 10, 2026 respectively.
| Parameter | Flowbox | Pipe Offset Calc |
|---|---|---|
| Price | Free | Free |
| Update frequency | Every 2 months | Every 5 days β better |
| Ads | No | No |
| In-app purchases | Yes | Yes |
| Devices | iPhone, iPad, iPod β better | iPhone, iPod |
| Requires iOS | 13.0 β better | 15.1 |
| Further details β not scored | ||
| Size | 25 MB | 22 MB |
| Age rating | 4+ | 4+ |
| Developer | GABRIELE CHESI | Aliaksei Shuliakouski |
In-app purchases
Flowbox
- Flowbox Pro Unlock$8.99
Pipe Offset Calc
- Unlock everything$12.99
Questions
Is Flowbox free?
Is Pipe Offset Calc free?
Do Flowbox or Pipe Offset Calc have ads?
Which is updated more often, Flowbox or Pipe Offset Calc?
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