I’m so glad you’re here!

If you ever need support keeping your books organized, gaining clarity on your numbers, or freeing up time to focus on growing your business, I’d love to help support your business.

Kelsey Mastaller

A little bit about me…

With nearly 10 years of experience in accounting, I've navigated both the corporate world and the non-profit sector, honing my skills in managing finances with precision and care. Currently, I work with Numbers in Boxes, supporting women-owned businesses and nonprofits by handling their financial needs, so they can focus on what they do best—growing and making a positive impact. Outside of numbers, I’m an avid traveler, and I bring the same sense of excitement and curiosity to bookkeeping as I do to exploring the world.

Let’s definitely stay in touch!

Kelsey
Bookkeeper / Account Manager

T: (617) 531-7134 ext. 5
E: kelsey@numbersinboxes.com

>> Meet the rest of the team!

If you’re ready to focus more on your mission…

We can take care of the numbers.

Numbers in Boxes provides bookkeeping, cash flow, payroll, and financial operations support to nonprofits and women-owned businesses with expert-level care—so you can focus on running your business with confidence.

SEE OUR MONTHLY PACKAGES

Go from drowning in spreadsheets → to Financial Clarity.

Go from drowning in spreadsheets → to Financial Clarity.

Two women fist bumping outdoors, with blurred park benches and greenery in the background.

Go from money dread → to Feeling Supported, Confident and in Control.

Go from money dread → to Feeling Supported, Confident and in Control.

A woman sitting at a desk with a silver MacBook, a smartphone, and a pen holder, stretching her arms behind her head while looking to the side. A bouquet of flowers is in the foreground.

Go from limited budgets → to Smart, Confident Decisions with ROI and a Plan B In Hand.

Go from limited budgets → to Smart, Confident Decisions with ROI and a Plan B In Hand.

A woman holding fanned out U.S. dollar bills in front of her face, with a blurred background and white walls.