Comparison

SigiCalc vs GT Graph

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

Head to head
About

SigiCalc

This app provides a graphical RPN calculator with an undo feature. Users can input mathematical equations and instantly visualize them with a plot. It's designed for simplicity and practicality in mathematical calculations.

Highlights
  • Graphical RPN calculator
  • Equation plotting
  • Undo functionality
  • Simple interface
  • Practical calculations
Features
Read full description

SigiCalc is a fast, clean RPN calculator that draws your functions. Enter a calculation the RPN way – numbers first, then the operation – and as soon as your expression contains X, tap Graph to see it plotted. No equals key, no parentheses, no fuss. REAL RPN • Classic stack-based entry with Enter, Undo and All Clear • Keys light up only when the stack has enough values – you can't make an invalid entry • The display shows your result, the whole expression in normal notation and the raw stack LIVE FUNCTION GRAPHS • Use X as a variable and plot the result instantly • Pinch to zoom, drag to pan, tap to zoom in, double-tap to reset • Touch and hold to read the exact x / y value on the curve • Discontinuities like tan(x) or 1/x are drawn correctly – no misleading vertical lines SCIENTIFIC FUNCTIONS sin, cos, tan and their inverses, natural log, square, square root, reciprocal, sign change and π DESIGNED FOR TODAY'S DEVICES • Light and Dark Mode, portrait and landscape • iPad: calculator and live graph side by side • Smooth animations and haptic feedback PRIVATE BY DESIGN SigiCalc works entirely on your device. No account, no network, no ads, no tracking. Example: X ↲ X sin × plots x · sin(x). What changed versus your text and why: - Leads with a benefit, not a category: "draws your functions" is the hook; "simple and practical graphical" told the reader nothing they'd search for. - Explains RPN in one sentence for people who don't know it, since that's the biggest reason someone bounces. - Bulleted feature blocks — App Store descriptions are skimmed, and the capitalised headings scan well in the store's plain-text rendering. - Adds Dark Mode / iPad / privacy, all of which are new in 3.0 and are things reviewers and users look for. - Fixed "polish" → "Polish" and "equation" → "expression" (you plot expressions, not equations).

About

GT Graph

Read full description

GT Graph transforms your device into a powerful mathematical visualization tool. Plot equations, explore calculus concepts, and bring mathematics to life with stunning interactive graphs. PLOT ANY EQUATION - Cartesian functions - Polar curves - Parametric equations - Implicit equations - Inequalities with shaded regions INTUITIVE INPUT Type equations naturally with implicit multiplication support. Write 2x instead of 2*x, or 2sin(x) instead of 2*sin(x). GT Graph understands mathematical notation the way you write it. COMPREHENSIVE FUNCTION LIBRARY - Trigonometric: sin, cos, tan, sec, csc, cot - Inverse trigonometric: asin, acos, atan - Hyperbolic: sinh, cosh, tanh - Exponential and logarithmic: exp, ln, log, log2 - Power functions: sqrt, cbrt, abs - Constants: pi, e, phi (golden ratio) MULTIPLE GRID TYPES - Standard Cartesian grid - Trigonometric grid with pi-labeled axes - Polar coordinate grid with radial lines - Logarithmic scale grid CALCULUS TOOLS - Calculate derivatives at any point - Compute definite integrals with visual shading - Find zeros (roots) of functions - Locate local minima and maxima - Generate value tables INTERACTIVE EXPLORATION - Pinch to zoom, drag to pan - Tap to show tangent lines - Crosshair cursor displays coordinates - Plot multiple equations simultaneously - Color-coded graphs for easy identification SAVE AND SHARE - Save your work as .gtgraph files - Export and share with colleagues - Equation history saves your last 25 entries - Settings persist between sessions Perfect for: - Students learning algebra, trigonometry, and calculus - Teachers creating visual demonstrations - Engineers and scientists visualizing data - Anyone curious about mathematical beauty GT Graph combines the power of professional graphing software with the elegance of modern design. Start plotting today!

Screenshots

SigiCalc4 screens
GT Graph4 screens

Verdict

The call

The clearest difference is in-app purchases: SigiCalc at none against GT Graph's 1. GT Graph's advantage is update cadence (every 8 days vs every 48 months). On price, ads, device support and iOS requirement there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. GT Graph sells 1 one-off in-app purchase. SigiCalc asks for nothing beyond the download.

UpkeepUpdate frequency

SigiCalc ships an update every 48 months, GT Graph every 8 days. The most recent releases landed on October 13, 2026 and October 8, 2026 respectively.

Scorecard2 real differences · 8 level
SigiCalc versus GT Graph: the parameters behind the verdict, then further details
ParameterSigiCalcGT Graph
PriceFreeFree
Rating5.0 (1 ratings) — better—
Positive reviews50.0% of reviews—
Number of ratings1 — better—
Update frequencyEvery 48 monthsEvery 8 days — better
AdsNoNo
In-app purchasesNo — betterYes
MonetizationFree—
DevicesiPhone, iPadiPhone, iPad, Mac — better
Requires iOS17.0 — better18.0
Further details — not scored
Size3 MB1 MB
Age rating4+4+
DeveloperSiegwareGennaro Eduardo Tangari

In-app purchases

None

SigiCalc

No in-app purchases

1 purchases

GT Graph

One-time1
  • GT Graph In-App Purchase$0.99

Questions

Is SigiCalc free?
SigiCalc is free to download, with no in-app purchases.
Is GT Graph free?
GT Graph is free to download, with in-app purchases available.
Do SigiCalc or GT Graph have ads?
Neither SigiCalc nor GT Graph shows ads.
Which is updated more often, SigiCalc or GT Graph?
SigiCalc ships an update every 48 months, and GT Graph every 8 days. Most recently, SigiCalc was updated on October 13, 2026 and GT Graph on October 8, 2026.

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