Online calculators that save you cash

Published: Monday, January 1, 2007 at 6:01 a.m.
Last Modified: Sunday, December 31, 2006 at 12:53 a.m.
Oh, dread. The electricity bill has arrived again. Not only are the numbers gargantuan, but you have no clue how the total climbed that high.
Saving money comes down to cost per unit in almost every case - cents per ounce at the grocery store, miles per gallon at the gas station, kilowatts per hour on the electric bill and cents per minute on the cell phone bill.
But if you look at the minutiae of your major expenses, you can begin to see how things add up. The good news? There are online calculators that do most of the work for you, and we've analyzed a few to see if they're accurate.
  • Fuel economy: Talk about personalized. This U.S. Department of Energy site has a "Your MPG" feature, which tracks your fuel economy and compares it with EPA test ratings and the miles per gallon of others with the same vehicle (sharing your information is optional). It also allows you to maintain a fuel purchase record, which tracks how much you are spending on gasoline. You have to do the calculations yourself, but this site walks you through.
  • Fuel cost calculator: This site, run by AAA, has a simple calculator that estimates the cost of a trip before you hit the road, using current regional gasoline averages.
    For example: A trip from Dallas to Houston is about 478 miles round trip. If 15.94 gallons of gas are used in a 1999 Nissan Sentra, the estimated cost will be $32.82, not including stops for fast food.
  • Hybrid car cost calculator: Thinking about purchasing a hybrid vehicle? This Department of Energy site will allow you to compare the lifetime costs and air emissions of a hybrid to those of a conventional vehicle. It even has data on makes and models, so you won't have to enter any information.
    For example: Compare a 4-cylinder Toyota Prius to a 6-cylinder Ford Escape. For the Prius, the purchase price is $19,222, with a fuel economy of 60 mpg in the city and 51 on the highway. The Ford Escape, at $23,280, gets 18 mpg in the city and 22 on the highway.
    Enter your annual mileage (15,000), the lifespan of your vehicle (7 years) and average gasoline cost ($2.20). Other factors are resale value and annual maintenance costs. Enter yours or use the site's default for your chosen vehicles. In this case, the cumulative cost of the Prius over seven years was $20,838.30 (taking into consideration a resale value of $5,598.53), while the cumulative cost of the Escape was $30,914.28 (with a resale value of $6,269.98). That's an average annual savings of $1,439.43 and an average per-mile savings of $0.10 with the Prius.
  • Mortgage refinancing calculator: This site run by a financial research group offers many personal-finance calculators, from determining mortgage payments to deciding between buying or leasing a car. Thinking about refinancing? One calculator offers personalized information by checking mortgage lenders in your ZIP code. On the home page, click on "Calculators" tab at the top. Then on "Should you refinance your mortgage?" under "Mortgage Calculators."
    For example: Your monthly payment is $1,200, your balance is $100,000 at 6.5 percent and you've got 15 years left on your loan. You want a loan term of 15 years at an interest rate of 5.5 percent. Your new payment would be $817.08.
    This doesn't include application fees, title searches and appraisal fees, so get that info before you calculate.
  • Saving vs. borrowing calculator: Need more information about financial aid for your college-bound student? Check out this site, run by, which offers a college cost projector, a loan calculator, an expected family contribution calculator, a student budget calculator and more. We'll look at the saving vs. borrowing calculator, which analyzes the benefits of saving beforehand vs. taking out loans for school.
    For example: If you save $200 a month for 10 years before school at a savings interest rate of 5.38 percent, your total savings will be $31,838.18. If you take out that much in a loan, with an interest rate of 8.5 percent and fees of 4 percent, you'll end up with monthly payments of $411.20 for the 10 years after school. That's more than double the payment per month of saving ahead of time.
  • Retirement calculator: The retirement calculator at the American Association of Retired Persons site helps you determine how much you'll need to retire on and how to get there from where you are. On the home page, click on "Money and Work," then "Financial Planning and Retirement" on the left-hand menu. Scroll down to "Session 7: Retirement Planning," and click on "Retirement Planning Calculator," then scroll down to the calculator link.
    The first section analyzes your retirement needs. First, enter you and your spouse's age, expected retirement age, life expectancy, salary and desired household income.
    If you don't know how much money you'll need, click on "estimate" and another calculator pops up and asks you to enter monthly expenses.
    In the funding section, enter details, such as current retirement assets, monthly contributions and estimated investment returns.
    This tool estimates the expected return on your investment based on whether you invest aggressively, moderately or conservatively during various pre-retirement periods.
    You also enter post-retirement income, such as pension and Social Security, and it links to the benefits calculator on the Social Security Web site (
  • Home energy analysis: Gather 12 months of energy bills and go to this government-funded site dedicated to energy efficiency to determine your monthly and annual usage. The site also will compare your home's efficiency to similar homes across the country and offers home improvements that save on energy costs.
    You'll enter basic information about your home, including square footage (conditioned floor area), number of inhabitants and year it was built. You then enter your energy usage and bill amounts for each month or for the last year.
  • Cell phone plan comparison: This retail site allows you to compare plans and phones from different providers.
    For example: Select your desired number of monthly anytime minutes (let's say 1,000), and that your primary calling area is regional. For an individual plan, the tool tells you that the T-Mobile Regional Rate Plan best fits your needs.
    Still need help? According to the site, most wireless phones offer a built-in timer that tracks your cumulative usage. Reset your timer for when your monthly billing cycle begins.
    If you're considering buying a hybrid vehicle, like the Toyota Prius, consider using the hybrid car cost calculator: This Department of Energy site will allow you to compare the lifetime costs and air emissions to those of a conventional vehicle.
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