Flash wear calculator
Result
Write rate-
Total writes before wear-out-
Estimated lifetime-
Flash Wear Calculator
Estimate how long flash or EEPROM storage will last before hitting its rated program/erase cycle limit, given how often you write to it and how many sectors you spread writes across.
Why flash and EEPROM wear out
Each erase cycle stresses the oxide layer that traps charge in a flash cell, and after enough cycles a cell can no longer reliably hold its programmed state. Datasheets specify this as a minimum guaranteed number of program/erase cycles, not a hard cutoff, but writes well beyond that number risk data corruption.
Why wear-leveling matters so much
If every write always lands on the same physical location, that location alone absorbs all the wear and can fail while the rest of the chip is untouched. Spreading writes evenly across N sectors multiplies the effective endurance by N, which is why filesystems and logging libraries built for flash almost always rotate write locations instead of overwriting one fixed spot.
Picking a realistic write interval
The write interval matters more than the endurance rating in most real designs. A sensor logging once per day will not meaningfully wear out even budget flash over a normal product lifetime, while the same flash written every second would wear out in hours, which is why frequent-write use cases like data logging or wear-leveled filesystems need the endurance figure taken seriously.
FAQ
What counts as one write for endurance purposes?
One program/erase cycle to the same physical location, which for block-erase flash usually means erasing and reprogramming an entire page or sector even if only a few bytes changed, not just changing a single byte.
Does reading flash wear it out?
No. Endurance ratings are specifically about program/erase cycles. Reading a flash cell as many times as needed does not consume its write endurance, though very high read counts on some NAND flash can cause a separate effect called read disturb.
How many wear-leveling sectors should I assume for my design?
It depends entirely on your filesystem or library. A simple round-robin scheme across a dedicated flash region might use anywhere from a handful of sectors to the entire free space, so check your specific flash filesystem's documentation rather than assuming a number.
Why do coin-cell-powered devices sometimes avoid flash writes entirely?
Because flash writes draw a short but relatively large current spike, and low-power designs on constrained batteries sometimes prefer FRAM or battery-backed RAM, which both write faster and draw much less power per write, in addition to having far higher cycle endurance.
Is 10,000 cycles a reliable number for any microcontroller's internal flash?
No. It is a commonly cited figure, but real datasheets vary; some budget microcontroller families specify as few as 1,000 cycles, while some higher-endurance memory regions in newer parts specify 100,000 or more. Always confirm the number against your specific part's datasheet.