Buy Now, Pay Later
As low as
$7
/ mo
Learn more
- – 4-month term
- – No impact on credit to apply
- – Instant approval decision
- – Secure and straightforward checkout
Ready to go? Add this product to your cart and select a plan during checkout.
Payment plans are offered through our trusted finance partners Klarna, Affirm, Afterpay, Apple Pay, and PayTomorrow. No-credit-needed leasing options through Acima may also be available at checkout.
Learn more about financing & leasing here.
Free shipping on this product
30-day returns
Learn more
FREE 30-day refund/replacement
To qualify for a full refund, items must be returned in their original, unused condition. If an item is returned in a used, damaged, or materially different state, you may be granted a partial refund.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
Availability:
In Stock.
Arrives
Sunday, Jun 21
Features
- Redesigned ES PLUS series calculators featuring easy-to-understand Natural Textbook Display, Non-Programmable Scientific Calculator with 417 Functions
- Stylish design but same function as Casio FX-991ESPLUS 1st edition, 10-digit mantissa + 2-digit exponential display
- Basic Trigonometrical & Statistics Functions, and many more functions
- Colour coded keypad for easy key differentiation, Simple and easy to use, Comes with new slide on hard case
Description
417 functions, Display: Natural Textbook Display, LCD (dot-matrix), 10 + 2 decimal places, Power supply: Solar & Battery, Basic Mathematical Functions, Table Generation, Base-n calculation, Scientific Constants, Vector, Basic Statistics, Differentiation, Non Graphing, Matrix, Equation, Integration, Complex number calculation, Comes with new slide-on hard case, Size (H x W x D): 11.1 x 77.0 x 161.5 mm, Weight: 95g
Brand: Casio
Color: Black
Calculator Type: Engineering/Scientific, Graphing
Power Source: Battery Powered
Screen Size: 4 Inches
Calculator Type: Engineering/Scientific, Graphing
Power Source: Battery Powered
Screen Size: 4 Inches
Number of Batteries: 1 LR44 batteries required. (included)
Display Type: LCD
Color: Black
Enclosure Material: Metal or Durable Plastic
Item Dimensions L x W: 6.38"L x 3.03"W
Brand: Casio
Model Name: fx-991ES PLUS 2nd edition
Global Trade Identification Number: 73
Manufacturer: CASIO
Mfr Part Number: C79
Model Number: FX-991ES PLUS 2ND EDITION
Item Weight: 95 Grams
Frequently asked questions
If you place your order now, the estimated arrival date for this product is:
Sunday, Jun 21
Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
To initiate a return, please visit our Returns Center.
View our full returns policy here.
- Klarna Financing
- Affirm Pay in 4
- Affirm Financing
- Afterpay Financing
- PayTomorrow Financing
- Financing through Apple Pay
Learn more about financing & leasing here.
Similar Products
Top Amazon Reviews
UPDATE: I thought the U.S. version of this was the update to this model, the ClassWiz one with menus replacing some of the printed-on functions. That is indeed an update (but maybe to the EX versions rather than, or in addition to, ES versions? Because EX versions are discontinued). But actually the U.S. version of the 991ES is the Fx-115ES. I had thought that because of its lower number, it was just a lower-grade model. But in fact it is essentially the same as the 991ES with a few more capabilities and white instead of black. I like this calculator a lot so I wanted a "spare" plus it is nice to always have one of the two within easy reach, so I got the U.S. version as well. They are both similar high quality, just different colors. I am very pleased with these calculators. Previous review: I've used RPN HP calculators for years and didn't expect to enjoy or appreciate this non-RPN calculator as much as I do. The main reason I got it was that I found a couple of lovely calculator apps for Android that I figured out were supposed to mimic the 911 series Casio, and so I wanted the real thing. It has been easy and intuitive to figure out how to use. As someone else commented, this seems to be for Indian market so you probably won't have US warranty. But the US version is totally different; you have to access many of the functions through menus and they are not printed on/above the keys. But having them printed instead of having to access through menus is much more efficient once you learn where things are. The US menu version is maybe best for people who want to use the calculator briefly and/or don't want to bother learning it (like people used to a different brand). You might have to go to a non-US Casio site to find the pdf manual for the 991ES. It would have been nice to include a hard copy of the manual but these days that's rare, and I'm fine with this because it keeps prices down. US version is now ClassWiz which sadly replaced the 991 ES and 911 EX. So you have no choice but to get a non-US-market one if you want the ES or EX (but Amazon also sells a copy-cat version of the 911ES/EX from a different brand). As far as the hardware: The calculator has a nice look and feel. The plastic is premium and nice. The upper (smaller) keys feel nicer to me, especially as a (classic) HP user. The bottom (bigger) keys are a bit squishy but that's normal for most calculators. I like that there are no soft rubber keys or other soft parts (because soft plastics often get old and sticky and gross). The case goes on and off smoothly and does not scratch the calculator. I am glad I got this calculator and I'm sad that Casio is switching to a simplified look, menu-driven, version at least for the U.S. market.
...
show more
Reviewed in the United States on March 15, 2024 by Ski9
Amazing item. Quality is good. Highly recommended if you want to do calculations. It’s very good with the numbering. I am an engineering student. Everything is working fine for me. Remember, not for graphing. If you are looking to graph, this is not the product. Otherwise amazing. Highly recommended. And very easy to use
...
show more
Reviewed in the United States on October 14, 2025 by MUSA MD FAHIM ISLAM
If you’re looking into different calculators chances are you’re probably taking advance STEM classes and your teachers don’t allow graphing calculators or your SAT or ACT may not allow it. Well you’ve come to the right place because this calculator works wonders. I know it might sound odd at first but as someone who’s finishing up an Aerospace Engineering degree I can say that this calculator has come in clutch in more ways than one. Whether you’re solving advanced physics problems, math, or science related problems this calculator has an application. All the different modes that come in this calculator will be able to assist you in many ways. It’s easy to use and understand, simply playing will the calculator will show you just how powerful it is. It’s great quality and the value for the price of the calculator is very worth it.
...
show more
Reviewed in the United States on August 25, 2024 by Adrian
If you're seeking a calculator that's easy to use and provide conversion sheets of different scientific units, this can be a great help. I love how simple Casio is when it comes to plugging in formulas and equations exactly as they're typed or written from your classes. It's best to take a few minutes to understand all the basic functions of the calculator because trust me, it will save you more often than you think, and helps cut down significant time from crunching numbers.
...
show more
Reviewed in the United States on May 6, 2026 by ArcticTropic
Why did you pick this product vs others?: Price and quality. Ease of use: Best engineering calculator I have ever used. Weight: Not heavy easy to carry even in my jeans pocket. Functionality: Very useful functions included for my mechanical engineering coursework.
Reviewed in the United States on June 30, 2025 by daunkim
I specifically bought this calculator because it supports hexadecimal calculations. It does but I had trouble with some calculations (I don't think it supports bigger numbers (32-bit)). Its an okay calculator but not as good as Window's Programmer calculator.
Reviewed in the United States on November 21, 2025 by Chris Pawlak
My daughter who is studying to be a mathematics teacher says this calculator is the BOSS. she says it works out fractions and is really good for people who are doing advanced mathematics. She loves it and I'm glad I bought it for her.
Reviewed in the United States on April 5, 2026 by cashiba
Casio scientific calculators are great with all the needed functionality. No unnecessary stuff. Just a gool ol' functioning calculator.
Reviewed in the United States on May 4, 2026 by dudetteabides