Comparison

Solve vs Date.Time Calculator

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

Head to head
About

Solve

This app offers a powerful graphing calculator with multiple functions. It solves expressions as you type and features an innovative memory system to store and recall answers. Easily plot 2D, 3D, polar, and time-based graphs with intuitive controls.

Highlights
  • Solves expressions as you type
  • Innovative memory system
  • Four distinct calculator tabs
  • 2D and 3D function plotting
  • Polar and time graphing
  • Plot multiple functions simultaneously
Features
Read full description

Solve is a calculator like no other! Solve solves expressions as you type and features an innovative memory system to store and recall answers. Simply touch the answer to store it and touch the stored answer to use it in an expression. Solve has four tabs that select four different calculators each with its own color. Multiply numbers, calculate a tip and find a square root all without clearing your results! Plot graphs with a single touch! Solve plots 2D and 3D functions using the x, y and θ variables. When you use the x, y and θ variables in an equation the answer will say Touch to Plot. Touch this label to graph the equation. GRAPHING Plot functions using the x variable. For example, "y=sin(x)" is just entered as "sin(x)". • cos(x) • abs(x) • x^2+2x+6 POLAR GRAPHING Plot polar equations using the θ variable. For example, "r=2θ" is just entered as "2θ". • 2θ • sin(2θ) 3D GRAPHING Plot 3D functions by using the x and y variables. For example, "z=x+y" is just entered as "x+y". • cos(x)+sin(y) • x^2+y^2 PLOT MULTIPLE GRAPHS Graph multiple functions by separating each equation with a comma. • sin(x),cos(x) • x,x^2,x^3 TIME GRAPHING The T variable is used to create animated or time plots. • cos(x+T) • sin(x+T)*x • cos(x+T)+sin(y+T) USER REVIEWS Really nice calculator by NeedHim "Having multiple calculators that you can use your calculations in is really a cool function. Prevents you from having to have a pad and paper to figure out multiple calculations. Also the colors are just incredible." Simply amazing. by oddgoingson "I was blown away by this app. When I first tried it and the tutorial came up, my first instinct was to skip past it. Then I started... Blown away. This calculator has everything and more. It is so logical for those who always wondered why calculators are sometimes so archaic. Forget copy and paste. Then I got to the graphing.... A must have period!" Perfect! by Michael "I've always hated how calculators didn't save answers. It made working out equations very hard and time consuming. But this app does that, and it does it well! Finally, a calculator app that actually works." Outstanding calculator -- full featured! by ofloveandhate "I have been using Solve for a few years now. Prompt updates, excellent controls, and a ton of features make it the best calculator I have used. I love having four separate units which I can use in each other and the plotting is easy as pi." Great app by biosci "It does everything I need in a 'fun' way that's intuitive to how I think and operate. I'll take it!" Great Calculator by Carl E. M. "This is a great calculator, aesthetically and functionally. Having the answer appear as you enter numbers will be the future of all calculators." I love this calculator by Alan63134 "I work on a shipping dock and it saves me a lot of time and headache. I can have 4 different calculator in one place. I can see the different weights or counts and know where I am if I have to do a lot of weighing or counting on different pallets. I use it every day. I also use it while shopping and can add the price of my shopping list and calculate what things cost. I love this calculator." Awesome! by smart-music-fan "This app is great. It easily graphs functions on the xy plane, and adding T as a variable to make the graph move is so fun. Its 3D graphing capability is great - quick, easy (it sets nice bounds on the z axis so you can see things clearly), and helpful for visualizing my Multivariable Calculus homework." Fantastic by xTricksterz "This app is beautiful, I use on my iPad and I'm first to answer most of the problems in class. This app shreds TI's calculator OS." Awesome!!! by llikeadodachacha "Does just about everything my TI-84 Plus but quicker and much easier to manipulate the graphs. It loads instantly and the 3D function is awesome for higher level math classes (I'm in Calc 3 now and it's already come in hand!)

About

Date.Time Calculator

Calculate date and time differences, intervals, and perform unit conversions with a pure calculator interface. Useful for determining future or past dates, calculating total time for multiple events, and converting between various time units and POSIX time.

Highlights
  • Date and time point calculations
  • Time interval calculations
  • Unit conversion of time
  • POSIX time interconversion
  • Time zone mutual conversion
  • Arithmetic operations with time
Features
Read full description

Date.Time Calculator lets you easily perform calculations involving dates, times, and time intervals, as well as convert between units of time — all with the familiar feel of a calculator. Date.Time Calculator supports the following operations: * Basic arithmetic with numbers (integers and decimals) * Arithmetic with numbers and Time Intervals * Operations between Time Intervals (addition, subtraction, and division) * Operations between Time Intervals and Time Points (addition and subtraction) * Operations between Time Points (calculating the difference) * Conversion between units of time * Conversion to and from POSIX Time * Conversion between time zones Date.Time Calculator is especially useful for questions such as: * What date is 100 days from today? * What date and time was it 32,768 seconds ago? * If one lap takes 1 minute 32.6 seconds, how long will 62 laps take? * What time will it be after those 62 laps? * How many days have passed since January 23 of this year? * How many days are 100,000 seconds? * What date and time does POSIX Time 1234567890 represent? * What is the current time in POSIX Time? And with a little creativity, Date.Time Calculator can be useful in many other situations as well.

Screenshots

Solve4 screens
Date.Time Calculator4 screens

Verdict

The call

The clearest difference is review sentiment: Solve at 82% against Date.Time Calculator's 0%. Solve also leads on update cadence (monthly vs every 5 months). Date.Time Calculator's advantage is price ($0.99 vs $1.99). On ads, in-app purchases, 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

Solve costs $1.99 and Date.Time Calculator $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Solve ships an update monthly, Date.Time Calculator every 5 months. The most recent releases landed on August 20, 2026 and September 9, 2026 respectively.

Scorecard4 real differences · 6 level
Solve versus Date.Time Calculator: the parameters behind the verdict, then further details
ParameterSolveDate.Time Calculator
Price$1.99$0.99 — better
Rating4.7 (198 ratings) — better—
Positive reviews82.5% of reviews — better0.0% of reviews
Number of ratings198 — better—
Update frequencyMonthly — betterEvery 5 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree — betterPaid
DevicesiPhone, iPad, iPod — betteriPhone, iPod
Requires iOS15.615.6
Further details — not scored
Size5 MB1 MB
Age rating4+4+
DeveloperPomegranate Apps LLCNoriaki HASHIBA

Customer experience

Solve

All ratings198 ratings
Positive94.4%
Neutral2.0%
Negative3.5%
Written reviews171 reviews
Positive82.5%
Neutral7.6%
Negative9.9%

Date.Time Calculator

Written reviews1 reviews
Positive0.0%
Neutral100.0%
Negative0.0%

Bugs and requests

Solve

Reported bugs

9 issues
  • Swipe up from bottom requires two swipes to exit app or switch apps
  • Home indicator hidden causes navigation issues
  • Floating-point arithmetic errors in decimal calculations
  • Inverse trigonometric functions (cos⁻¹, sin⁻¹) calculate in reverse
  • Graph plotting errors (e.g., sqrt(5²-x²) shows incomplete circle)
Show 4 more
  • Y-axis scale settings ignored in graphs
  • Page swiping interferes with app-switching gestures
  • Occasional decimal accuracy issues with multiple operations
  • Graph of sin(x)e(-x) doesn't reach zero as expected

Requested features

16 requests
  • Fix swipe-to-exit gesture conflict with iOS
  • Add percent button for quick percentage calculations
  • Implement undo/redo functionality
  • Add calculation history storage and management
  • Support for independent X/Y axis scaling
Show 11 more
  • Include derivative and integral calculations
  • Add more color/theme customization options
  • Implement trace feature for graphs with intersection detection
  • Support for polar coordinate 'r' variable
  • Add floor and ceil functions to UI
  • Tip/donation option for users
  • Larger buttons for easier use
  • Ability to interact with graphs (trace, zoom)
  • Support for cubed roots and other root functions
  • Spanish language localization
  • Gradient function for calculus

Date.Time Calculator

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Solve

No in-app purchases

None

Date.Time Calculator

No in-app purchases

Questions

Is Solve free?
Solve costs $1.99, with no in-app purchases.
Is Date.Time Calculator free?
Date.Time Calculator costs $0.99, with no in-app purchases.
Do Solve or Date.Time Calculator have ads?
Neither Solve nor Date.Time Calculator shows ads.
Which is updated more often, Solve or Date.Time Calculator?
Solve ships an update monthly, and Date.Time Calculator every 5 months. Most recently, Solve was updated on August 20, 2026 and Date.Time Calculator on September 9, 2026.

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