We are the MonoTape team. Before a long drive, you probably want a rough sense of how much gas the trip will eat and what it will cost. The math is not hard: distance divided by mileage gives gallons, gallons times price gives dollars. The annoying part is that the moment you change one figure — a detour, a price jump at the pump — you have to run the whole thing again. In this article we show how to set up a fuel estimate once and let it re-figure itself.
A plain calculator throws away the steps
Say the round trip is 320 miles and your car does about 30 mpg. Punch in 320 / 30 * 3.59 and a standard calculator hands you roughly $38. Fine — until the pump turns out to be $3.79, or you remember the drive is closer to 360 miles. Now you are typing the whole sequence again, and a moment later you cannot recall whether $38 was the cost or the gallons.
The trouble is not the arithmetic. It is that the calculator keeps no record of what each number meant. Distance, mileage, and price all blur into one chain, so adjusting any single input means starting over. That is exactly the gap MonoTape was built to close.
Lay the trip out with labels
In MonoTape you write the inputs with names, then build the result on top of them. Each line stays on the tape as a live value you can point back to.
Now the estimate is readable. If the pump is actually $3.79, you edit the Price line and the gallons and fuel cost recalculate on their own. Decide to take the scenic route? Bump Distance to 360 and watch both numbers follow. You never retype the formula — you just nudge the one input that changed. (If you think in km/L, the same setup works with kilometers and liters.)
Round trips and multiple legs add up cleanly
A real trip is rarely one straight shot. There is the drive out, the drive back, maybe a side trip to a trailhead. With a tape you simply give each leg its own line and total them.
Drop a leg, change a price, fix a mistyped distance — touch one line and the total reworks itself. Estimating fuel is a tool problem, not a math problem. Label the inputs, build the result on top, and edit only what changes. You walk out the door knowing roughly what the tank and the wallet are in for, and you can adjust on the fly.
MonoTape
A calculator notepad where you label your math and one edit recalculates everything. Fuel estimates, trip budgets, split bills — whatever you calculate stays on the tape. Free to use.
Learn more about MonoTapeFrequently asked questions
What if I think in km/L instead of mpg?
It works exactly the same. Label your distance in kilometers, your mileage in km/L, and your price per liter. The formulas reference those labels, so the unit you choose is up to you.
The gas price changed. Do I redo everything?
No. Edit the price line and every result that depends on it recalculates automatically. The same goes for distance or mileage — change the one input that moved and the estimate updates.
Can it handle a multi-leg trip?
Yes. Give each leg its own labeled line, sum them into a total distance, and build the fuel cost from there. Add or drop a leg and the total reworks itself.
Is it free?
Yes. Labeled calculations, references, auto-recalculation, and tape-style history — every feature mentioned here is free. Everything is stored locally on your device, and it works on both iPhone and Android.