AutoCalc

Free Car Calculators and Garage Log

Work out a car's on-road price and the loan's EMI, see through a flat rate, and check what your pay can carry. Compare what petrol, diesel, CNG and electric cars really cost to own, cost a trip or a charge, compare tyre sizes, and keep a garage log of your real mileage, spending and service dates. Everything is worked out in your browser, and nothing you type is uploaded.

Help guideFAQ

Units: km and km/LEverything stays in this browser.

Buying a car

The real on-road price, the loan and its EMI, what a "flat" rate really costs, part payments, and how much car your pay can carry.

Shortcuts, outside a text box: 1 to 6 open the six tools, U moves to the next units and ? opens the help.

How to Use AutoCalc: Step-by-Step

1

Price the car

Type the ex-showroom price from the dealer's list, your state's road tax, registration and the insurance quote. AutoCalc adds the TCS on a car over 10 lakh, takes off discounts and shows the on-road price.

2

Plan the loan

Choose the down payment, the rate the lender quotes and how long the loan runs. See the EMI, the interest, the real rate behind a flat rate, and how part payments end the loan sooner.

3

Compare what it costs to own

Add up to three cars with their price, real mileage, fuel price, insurance and service, and the resale you expect. See the cost a month and a km, and when the dearer one pays for itself.

4

Cost a trip or a charge

Type the distance, your mileage and the fuel price to see the trip's cost with tolls, split between friends. For an electric car, see the charging time and cost on each kind of charger.

5

Check tyres and power

Compare your tyre size with a new one and read the marks on the sidewall, the date it was made included. Convert power and torque, and see the speed in each gear.

6

Keep a garage log

Add your car or bike, log fill-ups, services and expenses, and see your real mileage and spending. Reminders come due by distance or date, and papers warn before they run out.

Why Use AutoCalc?

🧾 The price you really pay

The on-road price counts everything between the showroom and your driveway: road tax, registration, insurance, TCS, FASTag and extras, with discounts taken off.

🔍 Flat rates seen through

A quote at a "flat" rate is turned into the reducing rate banks use, so two loans can be compared fairly, and a processing fee is counted in the real cost.

⛽ Petrol, diesel, CNG or electric

Compare cars of any fuel on the same distance and years, and see whether the dearer one makes back its price in lower running costs before you sell it.

📏 Any unit you use

Kilometres or miles, km a litre, litres per 100 km or miles per gallon, and amounts as 45k, 8.5L or 1.2 cr. Change the units and every box is converted.

✍️ Your figures, not guesses

Fuel prices, road tax, the interest rate and the resale value are yours to type, because they differ by city, state, lender and car. The figures AutoCalc does use are named with their source.

🔒 Nothing uploaded

Everything is worked out in your browser and kept in this browser on this device. Save a backup file to move your garage log to another device; Delete everything removes it.

Car Costs Explained

🏷️ Ex-showroom and on-road

The ex-showroom price is the car with GST. The on-road price adds what it takes to drive it legally: road tax and registration, set by your state, and insurance. On a car over 10 lakh, 1% TCS is collected too and comes back as tax paid.

📉 Flat and reducing rates

A reducing rate charges interest only on what you still owe, so the interest falls as you repay. A flat rate charges it on the whole loan for the whole time: a flat 7% over five years costs about as much as a reducing 12.5%.

⛽ Full tank to full tank

The only honest mileage is measured: fill to the top, drive, fill to the top again, and divide the distance by what the second fill took. Logging every fill-up gives the average over months.

Frequently Asked Questions

Is AutoCalc free, and is anything I type uploaded?

It is free, with no registration and no limit. Like every page on ZeroDataUpload, it is supported by advertising. The prices, distances and log entries you type are worked out by your browser on your device and never sent to a server. They are kept in this browser's storage so they are there next time; Delete everything, under Settings, removes them.

How is the on-road price worked out?

The ex-showroom price, which already includes GST, plus the road tax your state charges, registration and number plates, the first year's insurance, FASTag, accessories and an extended warranty if you take them, less discounts. On a car priced over 10 lakh the dealer also collects 1% as tax collected at source (TCS). It is not a cost: it counts as tax you have already paid and comes back against your income tax.

How is the EMI worked out, and what is a flat rate?

The EMI uses the reducing-balance method banks use: each month's interest is charged only on what you still owe. A "flat" rate charges interest on the whole loan for the whole time, so it costs much more than the same number quoted as a reducing rate. Choose Flat and AutoCalc shows the real reducing rate behind it. A processing fee raises the real cost too, shown as the rate on the money you actually receive.

What does it really cost to own a car?

The value it loses, fuel or charging, insurance, service and loan interest, added up month by month over the years you keep it. AutoCalc does not guess the value lost: type the resale price you expect, or the share a car like yours loses in its first year and in each year after. Compare up to three cars and see when the dearer one pays back its higher price in lower running costs.

Can I fit a different tyre size?

Compare the two sizes. A common guide is to keep the overall diameter within about 3% of the original, so the speedometer, ABS and clearance stay close to what the car was built for, and to keep a load index and speed rating at least as high as the ones in the owner's manual. AutoCalc shows the change in diameter, what the speedometer reads and other sizes that keep the diameter.

How does the garage work out my real mileage?

Fill the tank to full and tick Full tank. The real mileage is the distance from one full tank to the next divided by all the fuel put in between, so a part fill is counted at the next full one. If you forgot to log a fill-up, tick "I missed logging the last fill-up" on the next one and that stretch is left out instead of spoiling the figure.

What is the IDV of my car?

The insured declared value is the most the insurer pays if the car is stolen or written off. It is the maker's listed price less a share for age set by the India Motor Tariff: 5% up to 6 months, 15% up to a year, then 20, 30, 40 and 50% for each year up to five. For a car over five years old, the IDV is agreed between you and the insurer.

How AutoCalc works

Six tools for buying, running and looking after a car or a bike. Answers change as you type; there is nothing to press. Everything you type stays in this browser on this device and is kept for next time.

Typing numbers

Amounts can be typed as 8.5L, 8.5 lakh, 45k, 1.2 cr or Rs 4,500, and sums work too: 450 + 300. Boxes with a unit beside them take the unit you pick there, so you can type miles in one box and km in another. The units switch at the top of the tool (or U) chooses km and km/L, km and L/100 km, US miles and mpg, or UK miles and mpg, and converts every box.

Buying a car

On-road price: the ex-showroom price (which already includes GST) plus road tax, which your state sets and which often differs for petrol, diesel and electric cars and by price, registration, insurance, TCS, FASTag and extras, less discounts. TCS is 1% of the price of a car over 10 lakh, collected by the dealer as tax already paid; you get it back against your income tax when you file your return.

The EMI uses the reducing-balance method that banks use: each month's interest is charged on what you still owe. Some dealers and lenders quote a "flat" rate, which charges interest on the full loan for the whole time; switch the rate to Flat to see the real rate behind it. A processing fee raises the real cost too, shown as the rate on the money you receive. Part payments keep your EMI the same and end the loan sooner. Under the RBI's rules a floating-rate loan to a person for personal use carries no part payment charges; check your own loan's terms.

The 20/4/10 rule is a common rule of thumb, not a law or a bank's rule: pay at least 20% down, borrow for at most 4 years, and keep the EMI and running costs under 10% of your monthly income.

The cost of owning

A car loses value every year. AutoCalc has no curve of its own for this, because no published figures for the used-car market fit every model: type the resale price you expect when you sell it, or the share a car like yours loses in its first year and in each year after (used-car listings for your model are the best guide). Until you do, the value lost is not counted and the page says so. Fuel prices rise each year by the rate you set (none if you leave it empty).

When comparing, the chart shows the money spent so far (the price plus fuel, insurance, service and interest); where two lines cross, the car that is dearer to buy has paid back its higher price. The totals also count what each car is worth when you sell it.

The insured declared value (IDV) follows the India Motor Tariff's table: the maker's listed price less 5% up to 6 months, 15% up to a year, then 20, 30, 40 and 50% for each year up to five. After five years it is agreed between you and the insurer.

Trips, fuel and charging

Fuel needed is the distance divided by the mileage. Use your real mileage, measured full tank to full tank: brochure figures are measured in a test cycle and are usually better than everyday driving. Stops count a refill when about 10% is left, or for an electric car a charge from 10 to 80%. CO2 is from burning the fuel: petrol 2.35 kg a litre and diesel 2.69 (the US EPA's figures for a gallon, 8,887 g and 10,180 g), CNG 2.75 kg a kg (counted as methane), and for electricity India's grid average for 2025-26, 0.675 kg a kWh (Central Electricity Authority).

Charging: home charging (AC) runs at the lower of the charger's and the car's power until nearly full. Fast charging (DC) slows after about half full and crawls above 80%, so stopping at 80% saves a lot of time. The times are an estimate: AutoCalc assumes typical charging curves and that 88% of the electricity reaches the battery on AC and 93% on DC, unless you type your own figure. Curves differ between cars.

Tyre sizes

In 205/55 R16 91V, 205 is the width in mm, 55 is the sidewall height as a percent of the width, R means radial, 16 is the rim in inches, 91 is the load index (615 kg per tyre) and V the speed rating (240 km/h); Z and (Y) mean over 240 and over 300 km/h. The overall diameter is the rim plus two sidewalls. A taller tyre turns fewer times per km, so the speedometer reads lower than your real speed; a smaller one makes it read higher. A common guide is to keep the diameter within about 3% of the original and the load index and speed rating at least as high.

The DOT code's last four digits are the week and year it was made: 2423 is week 24 of 2023. Rubber ages even when unused: Michelin advises a yearly check from 5 years old, and tyre makers advise replacing tyres 10 years after they were made at the latest (some car makers say 6). The legal minimum tread in many countries is 1.6 mm, where the wear bars sit; Continental advises replacing at 3 mm for grip on wet roads.

Power and performance

Power = torque x rpm / 9,549 (kW, Nm). One PS is 735.5 W, one hp is 745.7 W. The 0 to 100 km/h figure is a rough estimate from a simple model of the car accelerating with the grip of its driven wheels, the power that reaches them, gear changes, air drag and rolling resistance. Weight, tyres, launch control and the weather change real times; the maker's figure is the one to trust.

Gear speeds: road speed = rpm x tyre circumference / (gear ratio x final drive). The tyre size comes from the Tyres tab unless you type one.

Your garage

Fill the tank to full and tick "Full tank" each time you can. Real mileage is the distance from one full tank to the next divided by everything you put in between, so a part fill is counted at the next full one. If you forgot to log a fill-up, tick "I missed logging the last fill-up" on the next one so that stretch is left out. Service reminders come due by distance or by time, whichever is first; the date for the distance is worked out from how much you drive. The intervals filled in for a new vehicle are examples: change each one to your owner's manual. Calendar files add the due dates to your phone's calendar with an alert three days before.

Papers: in India a new vehicle needs no pollution certificate in its first year; after that a certificate lasts a year for BS-IV and BS-VI vehicles and six months for older ones. A private car's registration lasts 15 years and is then renewed for 5 years at a time.

Keyboard

1 to 6 switch tools, U moves to the next units, ? opens this help (outside a text box). ← and → move between the tabs and read a chart's values.

Figures are estimates for planning. Check prices, taxes and service intervals with your dealer, insurer, lender and owner's manual.