Comparison

Flowbox vs Pipe Offset Calc

Price, ratings, monetisation and update history for both apps, side by side β€” with what reviewers say about each.

Head to head
About

Flowbox

Features
Read full description

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.

About

Pipe Offset Calc

Features
Read full description

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

Flowbox4 screens
Pipe Offset Calc4 screens

Verdict

The call

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

CostPrice Β· In-app purchases Β· Ads Β· Monetization

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.

UpkeepUpdate frequency

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.

Scorecard2 real differences Β· 4 level
Flowbox versus Pipe Offset Calc: the parameters behind the verdict, then further details
ParameterFlowboxPipe Offset Calc
PriceFreeFree
Update frequencyEvery 2 monthsEvery 5 days β€” better
AdsNoNo
In-app purchasesYesYes
DevicesiPhone, iPad, iPod β€” betteriPhone, iPod
Requires iOS13.0 β€” better15.1
Further details β€” not scored
Size25 MB22 MB
Age rating4+4+
DeveloperGABRIELE CHESIAliaksei Shuliakouski

In-app purchases

1 purchases

Flowbox

One-time1
  • Flowbox Pro Unlock$8.99
1 purchases

Pipe Offset Calc

One-time1
  • Unlock everything$12.99

Questions

Is Flowbox free?
Flowbox is free to download, with in-app purchases available.
Is Pipe Offset Calc free?
Pipe Offset Calc is free to download, with in-app purchases available.
Do Flowbox or Pipe Offset Calc have ads?
Neither Flowbox nor Pipe Offset Calc shows ads.
Which is updated more often, Flowbox or Pipe Offset Calc?
Flowbox ships an update every 2 months, and Pipe Offset Calc every 5 days. Most recently, Flowbox was updated on November 6, 2026 and Pipe Offset Calc on November 10, 2026.

Other comparisons